diff --git a/ChangeLog b/ChangeLog
index 84202e00e..38705186b 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -6,6 +6,18 @@
 	  and epson. Added sanei_usb issues. Updated MacOS X and OS/2 porting
 	  issues.
 	* README.darwin: Updated.
+	* backend/gt68xx.c backend/gt68xx.conf backend/gt68xx_devices.c
+	  backend/gt68xx_high.c backend/gt68xx_high.h backend/gt68xx_low.c
+	  backend/gt68xx_low.h doc/sane-gt68xx.man doc/descriptions/gt68xx.desc
+	  doc/gt68xx/gt68xx.CHANGES:
+	  Coarse calibration for first scan only" is off by default now. Added gamma
+	  table factor option (SANE_CAP_EMULATED). Setup gamma to 2.0 by default.
+	  Fixed (hopefully) sigpipe when cancelling. No geometry quantization anymore
+	  (not necessary). Plustek 1248U: do linemode for every resolution, fix color
+	  correction. Added comments for every Model member in gt68xx_devices.
+	  Added Plustek UT16B and Genius Vivid3x to .desc. Added implementation for
+	  inverted offset for CCD scanners. Added Mustek ScanExpress 2400 USB. Well,
+	  at least it's detected. Added NEW marker to .desc.
 
 2002-12-07 Abel Deuring <a.deuring@satzbau-gmbh.de>
 	* sanei/sanei_scsi.c: improved error handling
diff --git a/backend/gt68xx.c b/backend/gt68xx.c
index 46df47238..426e98558 100644
--- a/backend/gt68xx.c
+++ b/backend/gt68xx.c
@@ -48,7 +48,7 @@
 
 #include "../include/sane/config.h"
 
-#define BUILD 31
+#define BUILD 32
 #define MAX_DEBUG
 #define WARMUP_TIME 30
 
@@ -79,6 +79,7 @@
 #include <unistd.h>
 #include <sys/time.h>
 #include <time.h>
+#include <math.h>
 
 #include "../include/sane/sane.h"
 #include "../include/sane/sanei.h"
@@ -124,15 +125,15 @@ static SANE_String_Const source_list[] = {
 };
 
 static SANE_Range x_range = {
-  SANE_FIX (0),			/* minimum */
-  SANE_FIX (216),		/* maximum */
-  SANE_FIX (0.1)		/* quantization */
+  SANE_FIX (0.0),		/* minimum */
+  SANE_FIX (216.0),		/* maximum */
+  SANE_FIX (0.0)		/* quantization */
 };
 
 static SANE_Range y_range = {
-  SANE_FIX (0),			/* minimum */
-  SANE_FIX (299),		/* maximum */
-  SANE_FIX (0.1)		/* quantization */
+  SANE_FIX (0.0),		/* minimum */
+  SANE_FIX (299.0),		/* maximum */
+  SANE_FIX (0.0)		/* quantization */
 };
 
 static const SANE_Range exposure_range = {
@@ -147,6 +148,12 @@ static const SANE_Range offset_range = {
   1				/* quantization */
 };
 
+static SANE_Range gamma_range = {
+  SANE_FIX (0.01),		/* minimum */
+  SANE_FIX (5.0),		/* maximum */
+  SANE_FIX (0.01)		/* quantization */
+};
+
 static const SANE_Range u8_range = {
   0,				/* minimum */
   255,				/* maximum */
@@ -488,7 +495,7 @@ init_options (GT68xx_Scanner * s)
   s->opt[OPT_COARSE_CAL_ONCE].type = SANE_TYPE_BOOL;
   s->opt[OPT_COARSE_CAL_ONCE].unit = SANE_UNIT_NONE;
   s->opt[OPT_COARSE_CAL_ONCE].constraint_type = SANE_CONSTRAINT_NONE;
-  s->val[OPT_COARSE_CAL_ONCE].w = SANE_TRUE;
+  s->val[OPT_COARSE_CAL_ONCE].w = SANE_FALSE;
 
   /* calibration */
   s->opt[OPT_QUALITY_CAL].name = SANE_NAME_QUALITY_CAL;
@@ -612,6 +619,18 @@ init_options (GT68xx_Scanner * s)
   s->opt[OPT_ENHANCEMENT_GROUP].size = 0;
   s->opt[OPT_ENHANCEMENT_GROUP].constraint_type = SANE_CONSTRAINT_NONE;
 
+  /* internal gamma value */
+  s->opt[OPT_GAMMA_VALUE].name = "gamma-value";
+  s->opt[OPT_GAMMA_VALUE].title = SANE_I18N ("Gamma value");
+  s->opt[OPT_GAMMA_VALUE].desc = SANE_I18N ("Sets the gamma value of all channels.");
+  s->opt[OPT_GAMMA_VALUE].type = SANE_TYPE_FIXED;
+  s->opt[OPT_GAMMA_VALUE].unit = SANE_UNIT_NONE;
+  s->opt[OPT_GAMMA_VALUE].constraint_type = SANE_CONSTRAINT_RANGE;
+  s->opt[OPT_GAMMA_VALUE].constraint.range = &gamma_range;
+  s->opt[OPT_GAMMA_VALUE].cap |= SANE_CAP_EMULATED;
+  s->val[OPT_GAMMA_VALUE].w = s->dev->gamma_value;
+  
+
   /* threshold */
   s->opt[OPT_THRESHOLD].name = SANE_NAME_THRESHOLD;
   s->opt[OPT_THRESHOLD].title = SANE_TITLE_THRESHOLD;
@@ -1224,6 +1243,7 @@ sane_open (SANE_String_Const devicename, SANE_Handle * handle)
   *handle = s;
   s->scanning = SANE_FALSE;
   s->first_scan = SANE_TRUE;
+  s->gamma_table = 0;
   RIE (init_options (s));
 
   DBG (5, "sane_open: exit\n");
@@ -1333,6 +1353,7 @@ sane_control_option (SANE_Handle handle, SANE_Int option,
 	case OPT_PREVIEW:
 	case OPT_LAMP_ON:
 	case OPT_AUTO_WARMUP:
+	case OPT_GAMMA_VALUE:
 	case OPT_THRESHOLD:
 	case OPT_SCAN_EXPOS_TIME_R:
 	case OPT_SCAN_EXPOS_TIME_G:
@@ -1396,6 +1417,7 @@ sane_control_option (SANE_Handle handle, SANE_Int option,
 	case OPT_AUTO_WARMUP:
 	case OPT_COARSE_CAL_ONCE:
 	case OPT_QUALITY_CAL:
+	case OPT_GAMMA_VALUE:
 	case OPT_THRESHOLD:
 	case OPT_SCAN_EXPOS_TIME_R:
 	case OPT_SCAN_EXPOS_TIME_G:
@@ -1531,7 +1553,7 @@ sane_start (SANE_Handle handle)
   GT68xx_Scan_Request scan_request;
   GT68xx_Scan_Parameters scan_params;
   SANE_Status status;
-  SANE_Int i;
+  SANE_Int i, gamma_size;
   unsigned int *buffer_pointers[3];
 
   DBG (5, "sane_start: start\n");
@@ -1571,6 +1593,26 @@ sane_start (SANE_Handle handle)
       s->dev->afe->b_pga = s->val[OPT_GAIN_B].w;
     }
 
+  s->dev->gamma_value = s->val[OPT_GAMMA_VALUE].w;
+  gamma_size = s->params.depth == 16 ? 65536 : 256;
+  s->gamma_table = malloc (sizeof (SANE_Int) * gamma_size);
+  if (!s->gamma_table)
+    {
+      DBG (1, "sane_start: couldn't malloc %d bytes for gamma table\n",
+	   gamma_size);
+      return SANE_STATUS_NO_MEM;
+    }
+  for (i = 0; i < gamma_size; i++)
+    {
+      s->gamma_table [i] = 
+	(gamma_size - 1) * pow (((double) i) / (gamma_size - 1),
+			  1.0 / SANE_UNFIX(s->dev->gamma_value)) + 0.5;
+      if (s->gamma_table [i] > (gamma_size - 1))
+	s->gamma_table [i] = (gamma_size - 1);
+      if (s->gamma_table [i] < 0) 
+	s->gamma_table [i] = 0;
+    }
+
   s->calib = s->val[OPT_QUALITY_CAL].w;
   RIE (gt68xx_device_stop_scan (s->dev));
 
@@ -1607,6 +1649,7 @@ sane_read (SANE_Handle handle, SANE_Byte * buf, SANE_Int max_len,
   static unsigned int *buffer_pointers[3];
   SANE_Int inflate_x;
   SANE_Bool lineart;
+  SANE_Int i, color, colors;
 
   if (!s)
     {
@@ -1655,6 +1698,11 @@ sane_read (SANE_Handle handle, SANE_Byte * buf, SANE_Int max_len,
   lineart = (strcmp (s->val[OPT_MODE].s, "Lineart") == 0)
     ? SANE_TRUE : SANE_FALSE;
 
+  if (s->reader->params.color)
+    colors = 3;
+  else
+    colors = 1;
+
   while ((*len) < max_len)
     {
       if (s->byte_count >= s->reader->params.pixel_xs)
@@ -1670,15 +1718,22 @@ sane_read (SANE_Handle handle, SANE_Byte * buf, SANE_Int max_len,
 	  RIE (gt68xx_scanner_read_line (s, buffer_pointers));
 	  s->line++;
 	  s->byte_count = 0;
-	  if (s->dev->model->flags & GT68XX_FLAG_MIRROR_X)
-	    {			/* mirror lines */
-	      int i, color, colors;
-	      unsigned int swap;
 
-	      if (s->reader->params.color)
-		colors = 3;
-	      else
-		colors = 1;
+	  /* Apply gamma */
+	  for (color = 0; color < colors; color++)
+	    for (i = 0; i < s->reader->pixels_per_line; i++)
+	      {
+		if (s->reader->params.depth > 8)
+		  buffer_pointers[color][i] = s->gamma_table[buffer_pointers[color][i]];
+		else
+		  buffer_pointers[color][i] = 
+		    (s->gamma_table[buffer_pointers[color][i] >> 8] << 8) +
+		    (s->gamma_table[buffer_pointers[color][i] >> 8]);
+	      }
+	  /* mirror lines */
+	  if (s->dev->model->flags & GT68XX_FLAG_MIRROR_X)
+	    {
+	      unsigned int swap;
 
 	      for (color = 0; color < colors; color++)
 		{
@@ -1815,6 +1870,9 @@ sane_cancel (SANE_Handle handle)
       gt68xx_scanner_stop_scan (s);
       gt68xx_scanner_wait_for_positioning (s);
       gt68xx_device_carriage_home (s->dev);
+      if (s->gamma_table)
+	free (s->gamma_table);
+      s->gamma_table = 0;
     }
   else
     {
diff --git a/backend/gt68xx.conf b/backend/gt68xx.conf
index b0fc96cef..6974b751c 100644
--- a/backend/gt68xx.conf
+++ b/backend/gt68xx.conf
@@ -16,6 +16,9 @@ usb 0x05d8 0x4002
 #vendor "Trust"
 #model "Compact Scan USB 19200"
 
+# Mustek ScanExpress 2400 USB
+#override "mustek-scanexpress-2400-usb"
+
 # Artec Ultima 2000, Boeder SmartScan Slim Edition,
 # Medion/Lifetec/Tevion/Cytron MD/LT 9385 and MD 9458,
 # Trust Flat Scan USB 19200
diff --git a/backend/gt68xx_devices.c b/backend/gt68xx_devices.c
index 578f7ca0e..3dc0e2ab5 100644
--- a/backend/gt68xx_devices.c
+++ b/backend/gt68xx_devices.c
@@ -50,11 +50,20 @@
 #include "gt68xx_gt6816.c"
 
 static GT68xx_Command_Set mustek_gt6816_command_set = {
-  "mustek-gt6816",
+  "mustek-gt6816",		/* Name of this command set */
 
-  0x200c, 0x200b,
-  0x2010, 0x3f40, 0x2011, 0x3f00,
-  0x2012, 0x3f40, 0x2013, 0x3f00,
+  0x200c,			/* Memory read - wValue */
+  0x200b,			/* Memory write - wValue */
+
+  0x2010,			/* Send normal command - wValue */
+  0x3f40,			/* Send normal command - wIndex */
+  0x2011,			/* Receive normal result - wValue */
+  0x3f00,			/* Receive normal result - wIndex */
+
+  0x2012,			/* Send small command - wValue */
+  0x3f40,			/* Send small command - wIndex */
+  0x2013,			/* Receive small result - wValue */
+  0x3f00,			/* Receive small result - wIndex */
 
   /* activate */ NULL,
   /* deactivate */ NULL,
@@ -78,9 +87,18 @@ static GT68xx_Command_Set mustek_gt6816_command_set = {
 static GT68xx_Command_Set mustek_gt6801_command_set = {
   "mustek-gt6801",
 
-  0x200a, 0x2009,
-  0x2010, 0x3f40, 0x2011, 0x3f00,
-  0x2012, 0x3f40, 0x2013, 0x3f00,
+  0x200a,			/* Memory read - wValue */
+  0x2009,			/* Memory write - wValue */
+
+  0x2010,			/* Send normal command - wValue */
+  0x3f40,			/* Send normal command - wIndex */
+  0x2011,			/* Receive normal result - wValue */
+  0x3f00,			/* Receive normal result - wIndex */
+
+  0x2012,			/* Send small command - wValue */
+  0x3f40,			/* Send small command - wIndex */
+  0x2013,			/* Receive small result - wValue */
+  0x3f00,			/* Receive small result - wIndex */
 
   /* activate */ NULL,
   /* deactivate */ NULL,
@@ -90,7 +108,7 @@ static GT68xx_Command_Set mustek_gt6801_command_set = {
   /* get_ta_status (FIXME: implement this) */ NULL,
   gt6801_lamp_control,
   gt6801_is_moving,
-  /*gt68xx_generic_move_relative *** to be tested */ NULL,
+  /* gt68xx_generic_move_relative *** to be tested */ NULL,
   gt6801_carriage_home,
   gt68xx_generic_start_scan,
   gt68xx_generic_read_scanned_data,
@@ -104,9 +122,18 @@ static GT68xx_Command_Set mustek_gt6801_command_set = {
 static GT68xx_Command_Set plustek_gt6801_command_set = {
   "plustek-gt6801",
 
-  0x200a, 0x2009,
-  0x2010, 0x3f40, 0x2011, 0x3f00,
-  0x2012, 0x3f40, 0x2013, 0x3f00,
+  0x200a,			/* Memory read - wValue */
+  0x2009,			/* Memory write - wValue */
+
+  0x2010,			/* Send normal command - wValue */
+  0x3f40,			/* Send normal command - wIndex */
+  0x2011,			/* Receive normal result - wValue */
+  0x3f00,			/* Receive normal result - wIndex */
+
+  0x2012,			/* Send small command - wValue */
+  0x3f40,			/* Send small command - wIndex */
+  0x2013,			/* Receive small result - wValue */
+  0x3f00,			/* Receive small result - wIndex */
 
   /* activate */ NULL,
   /* deactivate */ NULL,
@@ -116,230 +143,259 @@ static GT68xx_Command_Set plustek_gt6801_command_set = {
   /* get_ta_status (FIXME: implement this) */ NULL,
   gt6801_lamp_control,
   gt6801_is_moving,
-  /*gt68xx_generic_move_relative *** to be tested */ NULL,
+  /* gt68xx_generic_move_relative *** to be tested */ NULL,
   gt6801_carriage_home,
   gt68xx_generic_start_scan,
   gt68xx_generic_read_scanned_data,
   gt6801_stop_scan,
   gt6801_setup_scan,
   gt68xx_generic_set_afe,
-  NULL,
+  /* set_exposure_time */ NULL,
   gt68xx_generic_get_id
 };
 
 static GT68xx_Model mustek_2400ta_model = {
-  "mustek-bearpaw-2400-ta",
-  "Mustek",
-  "BearPaw 2400 TA",
-  "A2fw.usb",
-  SANE_FALSE,
+  "mustek-bearpaw-2400-ta",	/* Name */
+  "Mustek",			/* Device vendor string */
+  "BearPaw 2400 TA",		/* Device model name */
+  "A2fw.usb",			/* Name of the firmware file */
+  SANE_FALSE,			/* Dynamic allocation flag */
 
-  &mustek_gt6816_command_set,
+  &mustek_gt6816_command_set,	/* Command set used by this scanner */
 
-  1200,
-  2400,
-  1200,				/* ??? */
-  1200,
-  1200,
-  SANE_FALSE,
-  {1200, 600, 300, 200, 100, 50, 0},
-  {2400, 1200, 600, 300, 200, 100, 50, 0},
-  {16, 12, 8, 0},
-  {16, 12, 8, 0},
-  SANE_FIX (3.67),
-  SANE_FIX (7.4),
-  SANE_FIX (219.0),
-  SANE_FIX (298.0),
-  SANE_FIX (0.0),
-  SANE_FIX (0.635),
+  1200,				/* maximum optical sensor resolution */
+  2400,				/* maximum motor resolution */
+  1200,				/* base x-res used to calculate geometry */
+  1200,				/* base y-res used to calculate geometry */
+  1200,				/* if ydpi is equal or higher, use linemode */
+  SANE_FALSE,			/* Use base_ydpi for all resolutions */
 
-  SANE_FIX (94.0),
-  SANE_FIX (107.0),
-  SANE_FIX (37.0),
-  SANE_FIX (165.0),
-  SANE_FIX (95.0),
+  {1200, 600, 300, 200, 100, 50, 0},	/* possible x-resolutions */
+  {2400, 1200, 600, 300, 200, 100, 50, 0}, /* possible y-resolutions */
+  {16, 12, 8, 0},		/* possible depths in gray mode */
+  {16, 12, 8, 0},		/* possible depths in color mode */
 
-  0, 24, 48,			/* ??? */
-  0,
+  SANE_FIX (3.67),		/* Start of scan area in mm  (x) */
+  SANE_FIX (7.4),		/* Start of scan area in mm (y) */
+  SANE_FIX (219.0),		/* Size of scan area in mm (x) */
+  SANE_FIX (298.0),		/* Size of scan area in mm (y) */
 
-  COLOR_ORDER_RGB,
-  {0x2a, 0x0c, 0x2e, 0x06, 0x2d, 0x07},
-  {0x157, 0x157, 0x157},
-  SANE_FALSE,
-  0
+  SANE_FIX (0.0),		/* Start of white strip in mm (y) */
+  SANE_FIX (0.635),		/* Start of black mark in mm (x) */
+
+  SANE_FIX (94.0),		/* Start of scan area in TA mode in mm (x) */
+  SANE_FIX (107.0),		/* Start of scan area in TA mode in mm (y) */
+  SANE_FIX (37.0),		/* Size of scan area in TA mode in mm (x) */
+  SANE_FIX (165.0),		/* Size of scan area in TA mode in mm (y) */
+  SANE_FIX (95.0),		/* Start of white strip in TA mode in mm (y) */
+
+  0, 24, 48,			/* RGB CCD Line-distance correction in pixel */
+  0,				/* CCD distcance for CCD with 6 lines) */
+
+  COLOR_ORDER_RGB,		/* Order of the CCD/CIS colors */
+  {0x2a, 0x0c, 0x2e, 0x06, 0x2d, 0x07},	/* Default offset/gain */
+  {0x157, 0x157, 0x157},	/* Default exposure parameters */
+  SANE_FIX (2.0),		/* Default gamma value */
+
+  SANE_FALSE,			/* Is this a CIS scanner? */
+  0				/* Which flags are needed for this scanner? */
     /* flatbed values tested */
 };
 
 static GT68xx_Model mustek_2400taplus_model = {
-  "mustek-bearpaw-2400-ta-plus",
-  "Mustek",
-  "BearPaw 2400 TA Plus",
-  "A2Dfw.usb",
-  SANE_FALSE,
+  "mustek-bearpaw-2400-ta-plus",	/* Name */
+  "Mustek",			/* Device vendor string */
+  "BearPaw 2400 TA Plus",	/* Device model name */
+  "A2Dfw.usb",			/* Name of the firmware file */
+  SANE_FALSE,			/* Dynamic allocation flag */
 
-  &mustek_gt6816_command_set,
+  &mustek_gt6816_command_set,	/* Command set used by this scanner */
 
-  1200,
-  2400,
-  600,
-  1200,
-  1200,
-  SANE_FALSE,
-  {1200, 600, 300, 100, 50, 0},
-  {2400, 1200, 600, 300, 100, 50, 0},
-  {8, 0},
-  {16, 12, 8, 0},
-  SANE_FIX (7.41),
-  SANE_FIX (7.4),
-  SANE_FIX (217.5),
-  SANE_FIX (298.0),
-  SANE_FIX (0.0),
-  SANE_FIX (5.0),
+  1200,				/* maximum optical sensor resolution */
+  2400,				/* maximum motor resolution */
+  600,				/* base x-res used to calculate geometry */
+  1200,				/* base y-res used to calculate geometry */
+  1200,				/* if ydpi is equal or higher, use linemode */
+  SANE_FALSE,			/* Use base_ydpi for all resolutions */
 
-  SANE_FIX (94.0),
-  SANE_FIX (107.0),
-  SANE_FIX (37.0),
-  SANE_FIX (165.0),
-  SANE_FIX (95.0),
+  {1200, 600, 300, 100, 50, 0},	/* possible x-resolutions */
+  {2400, 1200, 600, 300, 100, 50, 0},	/* possible y-resolutions */
+  {8, 0},			/* possible depths in gray mode */
+  {16, 12, 8, 0},		/* possible depths in color mode */
 
-  0, 48, 96,
-  8,
+  SANE_FIX (7.41),		/* Start of scan area in mm  (x) */
+  SANE_FIX (7.4),		/* Start of scan area in mm (y) */
+  SANE_FIX (217.5),		/* Size of scan area in mm (x) */
+  SANE_FIX (298.0),		/* Size of scan area in mm (y) */
 
-  COLOR_ORDER_RGB,
-  {0x2a, 0x0c, 0x2e, 0x06, 0x2d, 0x07},
-  {0x157, 0x157, 0x157},
-  SANE_FALSE,
-  0
+  SANE_FIX (0.0),		/* Start of white strip in mm (y) */
+  SANE_FIX (5.0),		/* Start of black mark in mm (x) */
+
+  SANE_FIX (94.0),		/* Start of scan area in TA mode in mm (x) */
+  SANE_FIX (107.0) /* Start of scan area in TA mode in mm (y) */ ,
+  SANE_FIX (37.0),		/* Size of scan area in TA mode in mm (x) */
+  SANE_FIX (165.0),		/* Size of scan area in TA mode in mm (y) */
+
+  SANE_FIX (95.0),		/* Start of white strip in TA mode in mm (y) */
+
+  0, 48, 96,			/* RGB CCD Line-distance correction in pixel */
+  8,				/* CCD distcance for CCD with 6 lines) */
+
+  COLOR_ORDER_RGB,		/* Order of the CCD/CIS colors */
+  {0x2a, 0x0c, 0x2e, 0x06, 0x2d, 0x07},	/* Default offset/gain */
+  {0x157, 0x157, 0x157},	/* Default exposure parameters */
+  SANE_FIX (2.0),		/* Default gamma value */
+
+  SANE_FALSE,			/* Is this a CIS scanner? */
+  0				/* Which flags are needed for this scanner? */
     /* Setup and tested */
 };
 
 
 static GT68xx_Model mustek_1200ta_model = {
-  "mustek-bearpaw-1200-ta",
-  "Mustek",
-  "BearPaw 1200 TA",
-  "A1fw.usb",
-  SANE_FALSE,
+  "mustek-bearpaw-1200-ta",	/* Name */
+  "Mustek",			/* Device vendor string */
+  "BearPaw 1200 TA",		/* Device model name */
+  "A1fw.usb",			/* Name of the firmware file */
+  SANE_FALSE,			/* Dynamic allocation flag */
 
-  &mustek_gt6816_command_set,
+  &mustek_gt6816_command_set,	/* Command set used by this scanner */
 
-  600,
-  1200,
-  600,
-  600,
-  1200,
-  SANE_TRUE,
-  {600, 300, 150, 75, 50, 0},
-  {1200, 600, 300, 150, 100, 50, 0},
-  {16, 12, 8, 0},
-  {16, 12, 8, 0},
-  SANE_FIX (8.4),
-  SANE_FIX (7.5),
-  SANE_FIX (220.0),
-  SANE_FIX (299.0),
-  SANE_FIX (0.0),
-  SANE_FIX (7.0),
+  600,				/* maximum optical sensor resolution */
+  1200,				/* maximum motor resolution */
+  600,				/* base x-res used to calculate geometry */
+  600,				/* base y-res used to calculate geometry */
+  1200,				/* if ydpi is equal or higher, use linemode */
+  SANE_TRUE,			/* Use base_ydpi for all resolutions */
 
-  SANE_FIX (98.0),
-  SANE_FIX (108.0),		/* 109 */
-  SANE_FIX (37.0),
-  SANE_FIX (163.0),
-  SANE_FIX (95.0),
+  {600, 300, 150, 75, 50, 0},	/* possible x-resolutions */
+  {1200, 600, 300, 150, 100, 50, 0},	/* possible y-resolutions */
+  {16, 12, 8, 0},		/* possible depths in gray mode */
+  {16, 12, 8, 0},		/* possible depths in color mode */
 
-  32, 16, 0,			/* ??? */
-  0,
+  SANE_FIX (8.4),		/* Start of scan area in mm  (x) */
+  SANE_FIX (7.5),		/* Start of scan area in mm (y) */
+  SANE_FIX (220.0),		/* Size of scan area in mm (x) */
+  SANE_FIX (299.0),		/* Size of scan area in mm (y) */
 
-  COLOR_ORDER_RGB,
-  {0x2a, 0x0c, 0x2e, 0x06, 0x2d, 0x07},
-  {0x157, 0x157, 0x157},
-  SANE_FALSE,
-  0
-  /* Setup for 1200 TA */
+  SANE_FIX (0.0),		/* Start of white strip in mm (y) */
+  SANE_FIX (7.0),		/* Start of black mark in mm (x) */
+
+  SANE_FIX (98.0),		/* Start of scan area in TA mode in mm (x) */
+  SANE_FIX (108.0),		/* Start of scan area in TA mode in mm (y) */
+  SANE_FIX (37.0),		/* Size of scan area in TA mode in mm (x) */
+  SANE_FIX (163.0),		/* Size of scan area in TA mode in mm (y) */
+
+  SANE_FIX (95.0),		/* Start of white strip in TA mode in mm (y) */
+
+  32, 16, 0,			/* RGB CCD Line-distance correction in pixel */
+  0,				/* CCD distcance for CCD with 6 lines) */
+
+  COLOR_ORDER_RGB,		/* Order of the CCD/CIS colors */
+  {0x2a, 0x0c, 0x2e, 0x06, 0x2d, 0x07},	/* Default offset/gain */
+  {0x157, 0x157, 0x157},	/* Default exposure parameters */
+  SANE_FIX (2.0),		/* Default gamma value */
+
+  SANE_FALSE,			/* Is this a CIS scanner? */
+  0				/* Which flags are needed for this scanner? */
+    /* Setup for 1200 TA */
 };
 
 static GT68xx_Model mustek_1200cuplus_model = {
-  "mustek-bearpaw-1200-cu-plus",
-  "Mustek",
-  "Bearpaw 1200 CU Plus",
-  "PS1Dfw.usb",
-  SANE_FALSE,
+  "mustek-bearpaw-1200-cu-plus",	/* Name */
+  "Mustek",			/* Device vendor string */
+  "Bearpaw 1200 CU Plus",	/* Device model name */
+  "PS1Dfw.usb",			/* Name of the firmware file */
+  SANE_FALSE,			/* Dynamic allocation flag */
 
-  &mustek_gt6816_command_set,
+  &mustek_gt6816_command_set,	/* Command set used by this scanner */
 
-  600,
-  1200,
-  600,
-  600,
-  1200,
-  SANE_FALSE,
-  {600, 300, 150, 75, 50, 0},
-  {1200, 600, 300, 150, 75, 50, 0},
-  {16, 12, 8, 0},
-  {16, 12, 8, 0},
-  SANE_FIX (0.0),
-  SANE_FIX (13.0),
-  SANE_FIX (217.0),
-  SANE_FIX (299.0),
-  SANE_FIX (5.0),
-  SANE_FIX (0.0),		/* no black mark */
+  600,				/* maximum optical sensor resolution */
+  1200,				/* maximum motor resolution */
+  600,				/* base x-res used to calculate geometry */
+  600,				/* base y-res used to calculate geometry */
+  1200,				/* if ydpi is equal or higher, use linemode */
+  SANE_FALSE,			/* Use base_ydpi for all resolutions */
 
-  SANE_FIX (0.0),		/* no TA */
-  SANE_FIX (0.0),
-  SANE_FIX (100.0),
-  SANE_FIX (100.0),
-  SANE_FIX (0.0),
+  {600, 300, 150, 75, 50, 0},	/* possible x-resolutions */
+  {1200, 600, 300, 150, 75, 50, 0},	/* possible y-resolutions */
+  {16, 12, 8, 0},		/* possible depths in gray mode */
+  {16, 12, 8, 0},		/* possible depths in color mode */
 
-  0, 0, 0,
-  0,
+  SANE_FIX (0.0),		/* Start of scan area in mm  (x) */
+  SANE_FIX (13.0),		/* Start of scan area in mm (y) */
+  SANE_FIX (217.0),		/* Size of scan area in mm (x) */
+  SANE_FIX (299.0),		/* Size of scan area in mm (y) */
 
-  COLOR_ORDER_BGR,
-  {0x14, 0x07, 0x14, 0x07, 0x14, 0x07},
-  {0x157, 0x157, 0x157},
-  SANE_TRUE,
-  0
+  SANE_FIX (5.0),		/* Start of white strip in mm (y) */
+  SANE_FIX (0.0),		/* Start of black mark in mm (x) */
+
+  SANE_FIX (0.0),		/* Start of scan area in TA mode in mm (x) */
+  SANE_FIX (0.0),		/* Start of scan area in TA mode in mm (y) */
+  SANE_FIX (100.0),		/* Size of scan area in TA mode in mm (x) */
+  SANE_FIX (100.0),		/* Size of scan area in TA mode in mm (y) */
+
+  SANE_FIX (0.0),		/* Start of white strip in TA mode in mm (y) */
+
+  0, 0, 0,			/* RGB CCD Line-distance correction in pixel */
+  0,				/* CCD distcance for CCD with 6 lines) */
+
+  COLOR_ORDER_BGR,		/* Order of the CCD/CIS colors */
+  {0x14, 0x07, 0x14, 0x07, 0x14, 0x07},	/* Default offset/gain */
+  {0x157, 0x157, 0x157},	/* Default exposure parameters */
+  SANE_FIX (2.0),		/* Default gamma value */
+
+  SANE_TRUE,			/* Is this a CIS scanner? */
+  0				/* Which flags are needed for this scanner? */
     /* Everything untested */
 };
 
 static GT68xx_Model mustek_2400cuplus_model = {
-  "mustek-bearpaw-2400-cu-plus",
-  "Mustek",
-  "BearPaw 2400 CU Plus",
-  "PS2Dfw.usb",
-  SANE_FALSE,
+  "mustek-bearpaw-2400-cu-plus",	/* Name */
+  "Mustek",			/* Device vendor string */
+  "BearPaw 2400 CU Plus",	/* Device model name */
+  "PS2Dfw.usb",			/* Name of the firmware file */
+  SANE_FALSE,			/* Dynamic allocation flag */
 
-  &mustek_gt6816_command_set,
+  &mustek_gt6816_command_set,	/* Command set used by this scanner */
 
-  1200,
-  2400,
-  1200,
-  1200,
-  1200,
-  SANE_FALSE,
-  {1200, 600, 300, 200, 150, 100, 50, 0},
-  {2400, 1200, 600, 300, 200, 150, 100, 50, 0},
-  {16, 12, 8, 0},
-  {16, 12, 8, 0},
-  SANE_FIX (2.0),
-  SANE_FIX (13.0),
-  SANE_FIX (217.0),
-  SANE_FIX (300.0),
-  SANE_FIX (5.0),
-  SANE_FIX (0.0),		/* no black mark */
+  1200,				/* maximum optical sensor resolution */
+  2400,				/* maximum motor resolution */
+  1200,				/* base x-res used to calculate geometry */
+  1200,				/* base y-res used to calculate geometry */
+  1200,				/* if ydpi is equal or higher, use linemode */
+  SANE_FALSE,			/* Use base_ydpi for all resolutions */
 
-  SANE_FIX (0.0),		/* no TA */
-  SANE_FIX (0.0),
-  SANE_FIX (100.0),
-  SANE_FIX (100.0),
-  SANE_FIX (0.0),
+  {1200, 600, 300, 200, 150, 100, 50, 0},	/* possible x-resolutions */
+  {2400, 1200, 600, 300, 200, 150, 100, 50, 0},	/* possible y-resolutions */
+  {16, 12, 8, 0},		/* possible depths in gray mode */
+  {16, 12, 8, 0},		/* possible depths in color mode */
 
-  0, 0, 0,			/* no LD correction */
-  0,
+  SANE_FIX (2.0),		/* Start of scan area in mm  (x) */
+  SANE_FIX (13.0),		/* Start of scan area in mm (y) */
+  SANE_FIX (217.0),		/* Size of scan area in mm (x) */
+  SANE_FIX (300.0),		/* Size of scan area in mm (y) */
 
-  COLOR_ORDER_BGR,
-  {0x1a, 0x16, 0x15, 0x08, 0x0e, 0x02},
-  {0x157, 0x157, 0x157},
-  SANE_TRUE,
-  0
+  SANE_FIX (5.0),		/* Start of white strip in mm (y) */
+  SANE_FIX (0.0),		/* Start of black mark in mm (x) */
+
+  SANE_FIX (0.0),		/* Start of scan area in TA mode in mm (x) */
+  SANE_FIX (0.0),		/* Start of scan area in TA mode in mm (y) */
+  SANE_FIX (100.0),		/* Size of scan area in TA mode in mm (x) */
+  SANE_FIX (100.0),		/* Size of scan area in TA mode in mm (y) */
+
+  SANE_FIX (0.0),		/* Start of white strip in TA mode in mm (y) */
+
+  0, 0, 0,			/* RGB CCD Line-distance correction in pixel */
+  0,				/* CCD distcance for CCD with 6 lines) */
+
+  COLOR_ORDER_BGR,		/* Order of the CCD/CIS colors */
+  {0x1a, 0x16, 0x15, 0x08, 0x0e, 0x02},	/* Default offset/gain */
+  {0x157, 0x157, 0x157},	/* Default exposure parameters */
+  SANE_FIX (2.0),		/* Default gamma value */
+
+  SANE_TRUE,			/* Is this a CIS scanner? */
+  0				/* Which flags are needed for this scanner? */
     /* Setup and tested */
 };
 
@@ -347,310 +403,397 @@ static GT68xx_Model mustek_2400cuplus_model = {
  * and lots of other scanners have the same USB identifier.
  */
 static GT68xx_Model mustek_1200cu_model = {
-  "mustek-bearpaw-1200-cu",
-  "Mustek",
-  "BearPaw 1200 CU",
-  "PS1fw.usb",
-  SANE_FALSE,
+  "mustek-bearpaw-1200-cu",	/* Name */
+  "Mustek",			/* Device vendor string */
+  "BearPaw 1200 CU",		/* Device model name */
+  "PS1fw.usb",			/* Name of the firmware file */
+  SANE_FALSE,			/* Dynamic allocation flag */
 
-  &mustek_gt6801_command_set,
+  &mustek_gt6801_command_set,	/* Command set used by this scanner */
 
-  600,
-  1200,
-  600,
-  600,
-  1200,
-  SANE_TRUE,
-  {600, 300, 150, 75, 50, 0},
-  {1200, 600, 300, 150, 75, 50, 0},
-  {12, 8, 0},
-  {12, 8, 0},
-  SANE_FIX (0.0),
-  SANE_FIX (13.0),
-  SANE_FIX (217.0),
-  SANE_FIX (299.0),
-  SANE_FIX (3.5),
-  SANE_FIX (0.0),		/* no black mark */
+  600,				/* maximum optical sensor resolution */
+  1200,				/* maximum motor resolution */
+  600,				/* base x-res used to calculate geometry */
+  600,				/* base y-res used to calculate geometry */
+  1200,				/* if ydpi is equal or higher, use linemode */
+  SANE_TRUE,			/* Use base_ydpi for all resolutions */
 
-  SANE_FIX (0.0),		/* no TA */
-  SANE_FIX (0.0),
-  SANE_FIX (100.0),
-  SANE_FIX (100.0),
-  SANE_FIX (0.0),
+  {600, 300, 150, 75, 50, 0},	/* possible x-resolutions */
+  {1200, 600, 300, 150, 75, 50, 0},	/* possible y-resolutions */
+  {12, 8, 0},			/* possible depths in gray mode */
+  {12, 8, 0},			/* possible depths in color mode */
 
-  0, 0, 0,			/* no LD correction */
-  0,
+  SANE_FIX (0.0),		/* Start of scan area in mm  (x) */
+  SANE_FIX (13.0),		/* Start of scan area in mm (y) */
+  SANE_FIX (217.0),		/* Size of scan area in mm (x) */
+  SANE_FIX (299.0),		/* Size of scan area in mm (y) */
 
-  COLOR_ORDER_BGR,
-  {0x13, 0x04, 0x15, 0x06, 0x0f, 0x02},
-  {0x157, 0x157, 0x157},
-  SANE_TRUE,
-  0
+  SANE_FIX (3.5),		/* Start of white strip in mm (y) */
+  SANE_FIX (0.0),		/* Start of black mark in mm (x) */
+
+  SANE_FIX (0.0),		/* Start of scan area in TA mode in mm (x) */
+  SANE_FIX (0.0),		/* Start of scan area in TA mode in mm (y) */
+  SANE_FIX (100.0),		/* Size of scan area in TA mode in mm (x) */
+  SANE_FIX (100.0),		/* Size of scan area in TA mode in mm (y) */
+
+  SANE_FIX (0.0),		/* Start of white strip in TA mode in mm (y) */
+
+  0, 0, 0,			/* RGB CCD Line-distance correction in pixel */
+  0,				/* CCD distcance for CCD with 6 lines) */
+
+  COLOR_ORDER_BGR,		/* Order of the CCD/CIS colors */
+  {0x13, 0x04, 0x15, 0x06, 0x0f, 0x02},	/* Default offset/gain */
+  {0x157, 0x157, 0x157},	/* Default exposure parameters */
+  SANE_FIX (2.0),		/* Default gamma value */
+
+  SANE_TRUE,			/* Is this a CIS scanner? */
+  0				/* Which flags are needed for this scanner? */
     /* Setup and tested */
 };
 
 static GT68xx_Model mustek_scanexpress1200ubplus_model = {
-  "mustek-scanexpress-1200-ub-plus",
-  "Mustek",
-  "ScanExpress 1200 UB Plus",
-  "SBfw.usb",
-  SANE_FALSE,
+  "mustek-scanexpress-1200-ub-plus",	/* Name */
+  "Mustek",			/* Device vendor string */
+  "ScanExpress 1200 UB Plus",	/* Device model name */
+  "SBfw.usb",			/* Name of the firmware file */
+  SANE_FALSE,			/* Dynamic allocation flag */
 
-  &mustek_gt6801_command_set,
+  &mustek_gt6801_command_set,	/* Command set used by this scanner */
 
-  600,
-  1200,
-  600,
-  600,
-  1200,
-  SANE_TRUE,
-  {600, 300, 150, 75, 50, 0},
-  {1200, 600, 300, 150, 75, 50, 0},
-  {12, 8, 0},
-  {12, 8, 0},
-  SANE_FIX (0.0),
-  SANE_FIX (15.5),
-  SANE_FIX (217.0),
-  SANE_FIX (299.0),
-  SANE_FIX (6.5),
-  SANE_FIX (0.0),		/* no black mark */
+  600,				/* maximum optical sensor resolution */
+  1200,				/* maximum motor resolution */
+  600,				/* base x-res used to calculate geometry */
+  600,				/* base y-res used to calculate geometry */
+  1200,				/* if ydpi is equal or higher, use linemode */
+  SANE_TRUE,			/* Use base_ydpi for all resolutions */
 
-  SANE_FIX (0.0),		/* no TA */
-  SANE_FIX (0.0),
-  SANE_FIX (100.0),
-  SANE_FIX (100.0),
-  SANE_FIX (0.0),
+  {600, 300, 150, 75, 50, 0},	/* possible x-resolutions */
+  {1200, 600, 300, 150, 75, 50, 0},	/* possible y-resolutions */
+  {12, 8, 0},			/* possible depths in gray mode */
+  {12, 8, 0},			/* possible depths in color mode */
 
-  0, 0, 0,			/* no LD correction */
-  0,
+  SANE_FIX (0.0),		/* Start of scan area in mm  (x) */
+  SANE_FIX (15.5),		/* Start of scan area in mm (y) */
+  SANE_FIX (217.0),		/* Size of scan area in mm (x) */
+  SANE_FIX (299.0),		/* Size of scan area in mm (y) */
 
-  COLOR_ORDER_BGR,
-  {0x0f, 0x01, 0x15, 0x06, 0x13, 0x04},
-  {0x157, 0x157, 0x157},
-  SANE_TRUE,
-  0
+  SANE_FIX (6.5),		/* Start of white strip in mm (y) */
+  SANE_FIX (0.0),		/* Start of black mark in mm (x) */
+
+  SANE_FIX (0.0),		/* Start of scan area in TA mode in mm (x) */
+  SANE_FIX (0.0),		/* Start of scan area in TA mode in mm (y) */
+  SANE_FIX (100.0),		/* Size of scan area in TA mode in mm (x) */
+  SANE_FIX (100.0),		/* Size of scan area in TA mode in mm (y) */
+
+  SANE_FIX (0.0),		/* Start of white strip in TA mode in mm (y) */
+
+  0, 0, 0,			/* RGB CCD Line-distance correction in pixel */
+  0,				/* CCD distcance for CCD with 6 lines) */
+
+  COLOR_ORDER_BGR,		/* Order of the CCD/CIS colors */
+  {0x0f, 0x01, 0x15, 0x06, 0x13, 0x04},	/* Default offset/gain */
+  {0x157, 0x157, 0x157},	/* Default exposure parameters */
+  SANE_FIX (2.0),		/* Default gamma value */
+
+  SANE_TRUE,			/* Is this a CIS scanner? */
+  0				/* Which flags are needed for this scanner? */
     /* Setup and tested */
 };
 
 static GT68xx_Model artec_ultima2000_model = {
-  "artec-ultima-2000",
-  "Artec",
-  "Ultima 2000",
-  "Gt680xfw.usb",
-  SANE_FALSE,
+  "artec-ultima-2000",		/* Name */
+  "Artec",			/* Device vendor string */
+  "Ultima 2000",		/* Device model name */
+  "Gt680xfw.usb",		/* Name of the firmware file */
+  SANE_FALSE,			/* Dynamic allocation flag */
 
-  &mustek_gt6801_command_set,
+  &mustek_gt6801_command_set,	/* Command set used by this scanner */
 
-  600,
-  600,
-  600,
-  600,
-  600,
-  SANE_TRUE,
-  {600, 300, 200, 150, 100, 75, 50, 0},
-  {600, 300, 200, 150, 100, 75, 50, 0},
-  {12, 8, 0},
-  {12, 8, 0},
-  SANE_FIX (2.0),
-  SANE_FIX (7.0),
-  SANE_FIX (218.0),
-  SANE_FIX (299.0),
-  SANE_FIX (0.0),
-  SANE_FIX (0.0),		/* no black mark */
-  SANE_FIX (0.0),		/* no TA */
-  SANE_FIX (0.0),
-  SANE_FIX (100.0),
-  SANE_FIX (100.0),
-  SANE_FIX (0.0),
+  600,				/* maximum optical sensor resolution */
+  600,				/* maximum motor resolution */
+  600,				/* base x-res used to calculate geometry */
+  600,				/* base y-res used to calculate geometry */
+  600,				/* if ydpi is equal or higher, use linemode */
+  SANE_TRUE,			/* Use base_ydpi for all resolutions */
 
-  0, 0, 0,			/* no LD correction */
-  0,
+  {600, 300, 200, 150, 100, 75, 50, 0},	/* possible x-resolutions */
+  {600, 300, 200, 150, 100, 75, 50, 0},	/* possible y-resolutions */
+  {12, 8, 0},			/* possible depths in gray mode */
+  {12, 8, 0},			/* possible depths in color mode */
 
-  COLOR_ORDER_BGR,
-  {0x0f, 0x01, 0x15, 0x06, 0x13, 0x04},
-  {0x157, 0x157, 0x157},
-  SANE_TRUE,
-  GT68XX_FLAG_MIRROR_X | GT68XX_FLAG_MOTOR_HOME | GT68XX_FLAG_OFFSET_INV
+  SANE_FIX (2.0),		/* Start of scan area in mm  (x) */
+  SANE_FIX (7.0),		/* Start of scan area in mm (y) */
+  SANE_FIX (218.0),		/* Size of scan area in mm (x) */
+  SANE_FIX (299.0),		/* Size of scan area in mm (y) */
+
+  SANE_FIX (0.0),		/* Start of white strip in mm (y) */
+  SANE_FIX (0.0),		/* Start of black mark in mm (x) */
+
+  SANE_FIX (0.0),		/* Start of scan area in TA mode in mm (x) */
+  SANE_FIX (0.0),		/* Start of scan area in TA mode in mm (y) */
+  SANE_FIX (100.0),		/* Size of scan area in TA mode in mm (x) */
+  SANE_FIX (100.0),		/* Size of scan area in TA mode in mm (y) */
+
+  SANE_FIX (0.0),		/* Start of white strip in TA mode in mm (y) */
+
+  0, 0, 0,			/* RGB CCD Line-distance correction in pixel */
+  0,				/* CCD distcance for CCD with 6 lines) */
+
+  COLOR_ORDER_BGR,		/* Order of the CCD/CIS colors */
+  {0x0f, 0x01, 0x15, 0x06, 0x13, 0x04},	/* Default offset/gain */
+  {0x157, 0x157, 0x157},	/* Default exposure parameters */
+  SANE_FIX (2.0),		/* Default gamma value */
+
+  SANE_TRUE,			/* Is this a CIS scanner? */
+  GT68XX_FLAG_MIRROR_X | GT68XX_FLAG_MOTOR_HOME | GT68XX_FLAG_OFFSET_INV	/* Which flags are needed for this scanner? */
     /* Setup for Cytron TCM MD 9385 */
 };
 
 static GT68xx_Model mustek_2400cu_model = {
-  "mustek-bearpaw-2400-cu",
-  "Mustek",
-  "BearPaw 2400 CU",
-  "PS2fw.usb",
-  SANE_FALSE,
+  "mustek-bearpaw-2400-cu",	/* Name */
+  "Mustek",			/* Device vendor string */
+  "BearPaw 2400 CU",		/* Device model name */
+  "PS2fw.usb",			/* Name of the firmware file */
+  SANE_FALSE,			/* Dynamic allocation flag */
 
-  &mustek_gt6801_command_set,
+  &mustek_gt6801_command_set,	/* Command set used by this scanner */
 
-  1200,
-  2400,
-  1200,
-  1200,
-  2400,
-  SANE_TRUE,
-  {1200, 600, 300, 150, 100, 50, 0},
-  {2400, 1200, 600, 300, 150, 100, 50, 0},
-  {12, 8, 0},
-  {12, 8, 0},
-  SANE_FIX (0.0),		/* 0 */
-  SANE_FIX (13.5),		/* 1280, */
-  SANE_FIX (215.9),		/* 10240, */
-  SANE_FIX (296.7),		/* 28032, */
-  SANE_FIX (5.5),
-  SANE_FIX (0.0),		/* no black mark */
+  1200,				/* maximum optical sensor resolution */
+  2400,				/* maximum motor resolution */
+  1200,				/* base x-res used to calculate geometry */
+  1200,				/* base y-res used to calculate geometry */
+  2400,				/* if ydpi is equal or higher, use linemode */
+  SANE_TRUE,			/* Use base_ydpi for all resolutions */
 
-  SANE_FIX (0.0),		/* no TA */
-  SANE_FIX (0.0),
-  SANE_FIX (100.0),
-  SANE_FIX (100.0),
-  SANE_FIX (0.0),
+  {1200, 600, 300, 150, 100, 50, 0},	/* possible x-resolutions */
+  {2400, 1200, 600, 300, 150, 100, 50, 0},	/* possible y-resolutions */
+  {12, 8, 0},			/* possible depths in gray mode */
+  {12, 8, 0},			/* possible depths in color mode */
 
-  0, 0, 0,			/* no LD correction */
-  0,
+  SANE_FIX (0.0),		/* Start of scan area in mm  (x) */
+  SANE_FIX (13.5),		/* Start of scan area in mm (y) */
+  SANE_FIX (215.0),		/* Size of scan area in mm (x) */
+  SANE_FIX (296.9),		/* Size of scan area in mm (y) */
 
-  COLOR_ORDER_BGR,
-  {0x0f, 0x01, 0x15, 0x06, 0x13, 0x04},
-  {0x157, 0x157, 0x157},
-  SANE_TRUE,
-  0
+  SANE_FIX (5.5),		/* Start of white strip in mm (y) */
+  SANE_FIX (0.0),		/* Start of black mark in mm (x) */
+
+  SANE_FIX (0.0),		/* Start of scan area in TA mode in mm (x) */
+  SANE_FIX (0.0),		/* Start of scan area in TA mode in mm (y) */
+  SANE_FIX (100.9),		/* Size of scan area in TA mode in mm (x) */
+  SANE_FIX (100.0),		/* Size of scan area in TA mode in mm (y) */
+
+  SANE_FIX (0.0),		/* Start of white strip in TA mode in mm (y) */
+
+  0, 0, 0,			/* RGB CCD Line-distance correction in pixel */
+  0,				/* CCD distcance for CCD with 6 lines) */
+
+  COLOR_ORDER_BGR,		/* Order of the CCD/CIS colors */
+  {0x0f, 0x01, 0x15, 0x06, 0x13, 0x04},	/* Default offset/gain */
+  {0x157, 0x157, 0x157},	/* Default exposure parameters */
+  SANE_FIX (2.0),		/* Default gamma value */
+
+  SANE_TRUE,			/* Is this a CIS scanner? */
+  0				/* Which flags are needed for this scanner? */
     /* basically tested, details may need tweaking */
 };
 
+static GT68xx_Model mustek_scanexpress2400usb_model = {
+  "mustek-scanexpress-2400-usb",	/* Name */
+  "Mustek",			/* Device vendor string */
+  "ScanExpress 2400 USB",		/* Device model name */
+  "P9fw.usb",			/* Name of the firmware file */
+  SANE_FALSE,			/* Dynamic allocation flag */
+
+  &mustek_gt6801_command_set,	/* Command set used by this scanner */
+
+  600,				/* maximum optical sensor resolution */
+  1200,				/* maximum motor resolution */
+  1200,				/* base x-res used to calculate geometry */
+  600,				/* base y-res used to calculate geometry */
+  1200,				/* if ydpi is equal or higher, use linemode */
+  SANE_TRUE,			/* Use base_ydpi for all resolutions */
+
+  {600, 300, 150, 100, 50, 0},	/* possible x-resolutions */
+  {1200, 600, 300, 150, 100, 50, 0},	/* possible y-resolutions */
+  {8, 0},			/* possible depths in gray mode */
+  {8, 0},			/* possible depths in color mode */
+
+  SANE_FIX (15.0),		/* Start of scan area in mm  (x) */
+  SANE_FIX (25.0),		/* Start of scan area in mm (y) */
+  SANE_FIX (220.0),		/* Size of scan area in mm (x) */
+  SANE_FIX (299.0),		/* Size of scan area in mm (y) */
+
+  SANE_FIX (0.0),		/* Start of white strip in mm (y) */
+  SANE_FIX (7.0),		/* Start of black mark in mm (x) */
+
+  SANE_FIX (0.0),		/* Start of scan area in TA mode in mm (x) */
+  SANE_FIX (0.0),		/* Start of scan area in TA mode in mm (y) */
+  SANE_FIX (100.9),		/* Size of scan area in TA mode in mm (x) */
+  SANE_FIX (100.0),		/* Size of scan area in TA mode in mm (y) */
+
+  SANE_FIX (0.0),		/* Start of white strip in TA mode in mm (y) */
+
+  0, 16, 32,			/* RGB CCD Line-distance correction in pixel */
+  0,				/* CCD distcance for CCD with 6 lines) */
+
+  COLOR_ORDER_RGB,		/* Order of the CCD/CIS colors */
+  {0x16, 0x06, 0x16, 0x06, 0x16, 0x06},	/* Default offset/gain */
+  {0x157, 0x157, 0x157},	/* Default exposure parameters */
+  SANE_FIX (2.0),		/* Default gamma value */
+
+  SANE_FALSE,			/* Is this a CIS scanner? */
+  GT68XX_FLAG_UNTESTED		/* Which flags are needed for this scanner? */
+    /* only partly tested */
+};
+
 static GT68xx_Model mustek_a3usb_model = {
-  "mustek-scanexpress-a3-usb",
-  "Mustek",
-  "ScanExpress A3 USB",
-  "A32fw.usb",
-  SANE_FALSE,
+  "mustek-scanexpress-a3-usb",	/* Name */
+  "Mustek",			/* Device vendor string */
+  "ScanExpress A3 USB",		/* Device model name */
+  "A32fw.usb",			/* Name of the firmware file */
+  SANE_FALSE,			/* Dynamic allocation flag */
 
-  &mustek_gt6816_command_set,
+  &mustek_gt6816_command_set,	/* Command set used by this scanner */
 
-  300,
-  600,
-  300,
-  300,
-  300,
-  SANE_FALSE,
-  {300, 150, 95, 50, 0},
-  {600, 300, 150, 75, 50, 0},
-  {12, 8, 0},
-  {12, 8, 0},
-  SANE_FIX (2.0),
-  SANE_FIX (13.0),
-  SANE_FIX (300.0),
-  SANE_FIX (420.0),
-  SANE_FIX (5.0),
-  SANE_FIX (0.0),		/* no black mark */
+  300,				/* maximum optical sensor resolution */
+  600,				/* maximum motor resolution */
+  300,				/* base x-res used to calculate geometry */
+  300,				/* base y-res used to calculate geometry */
+  300,				/* if ydpi is equal or higher, use linemode */
+  SANE_FALSE,			/* Use base_ydpi for all resolutions */
 
-  SANE_FIX (0.0),		/* no TA */
-  SANE_FIX (0.0),
-  SANE_FIX (100.0),
-  SANE_FIX (100.0),
-  SANE_FIX (0.0),
+  {300, 150, 95, 50, 0},	/* possible x-resolutions */
+  {600, 300, 150, 75, 50, 0},	/* possible y-resolutions */
+  {12, 8, 0},			/* possible depths in gray mode */
+  {12, 8, 0},			/* possible depths in color mode */
 
-  0, 0, 0,			/* no LD correction */
-  0,
+  SANE_FIX (2.0),		/* Start of scan area in mm  (x) */
+  SANE_FIX (13.0),		/* Start of scan area in mm (y) */
+  SANE_FIX (300.0),		/* Size of scan area in mm (x) */
+  SANE_FIX (420.0),		/* Size of scan area in mm (y) */
 
-  COLOR_ORDER_RGB,
-  {0x14, 0x07, 0x14, 0x07, 0x14, 0x07},
-  {0x157, 0x157, 0x157},
-  SANE_TRUE,
-  GT68XX_FLAG_UNTESTED
-    /* Completely untested, doesn't seem to work */
+  SANE_FIX (5.0),		/* Start of white strip in mm (y) */
+  SANE_FIX (0.0),		/* Start of black mark in mm (x) */
+
+  SANE_FIX (0.0),		/* Start of scan area in TA mode in mm (x) */
+  SANE_FIX (0.0),		/* Start of scan area in TA mode in mm (y) */
+  SANE_FIX (100.0),		/* Size of scan area in TA mode in mm (x) */
+  SANE_FIX (100.0),		/* Size of scan area in TA mode in mm (y) */
+
+  SANE_FIX (0.0),		/* Start of white strip in TA mode in mm (y) */
+
+  0, 0, 0,			/* RGB CCD Line-distance correction in pixel */
+  0,				/* CCD distcance for CCD with 6 lines) */
+
+  COLOR_ORDER_RGB,		/* Order of the CCD/CIS colors */
+  {0x14, 0x07, 0x14, 0x07, 0x14, 0x07},	/* Default offset/gain */
+  {0x157, 0x157, 0x157},	/* Default exposure parameters */
+  SANE_FIX (2.0),		/* Default gamma value */
+
+  SANE_TRUE,			/* Is this a CIS scanner? */
+  GT68XX_FLAG_UNTESTED		/* Which flags are needed for this scanner? */
+    /* Mostly untested, margins seem to be wrong */
 };
 
 static GT68xx_Model lexmark_x73_model = {
-  "lexmark-x73",
-  "Lexmark",
-  "X73",
-  "OSLO3071b2.usb",
-  SANE_FALSE,
+  "lexmark-x73",		/* Name */
+  "Lexmark",			/* Device vendor string */
+  "X73",			/* Device model name */
+  "OSLO3071b2.usb",		/* Name of the firmware file */
+  SANE_FALSE,			/* Dynamic allocation flag */
 
-  &mustek_gt6816_command_set,
+  &mustek_gt6816_command_set,	/* Command set used by this scanner */
 
-  600,
-  1200,
-  600,
-  600,				/* ??? */
-  1200,				/* ??? */
-  SANE_TRUE,
+  600,				/* maximum optical sensor resolution */
+  1200,				/* maximum motor resolution */
+  600,				/* base x-res used to calculate geometry */
+  600,				/* base y-res used to calculate geometry */
+  1200,				/* if ydpi is equal or higher, use linemode */
+  SANE_TRUE,			/* Use base_ydpi for all resolutions */
 
-  {600, 300, 150, 75, 0},
-  {600, 300, 150, 75, 0},
-  {16, 12, 8, 0},
-  {16, 12, 8, 0},
-  SANE_FIX (6.519),
-  SANE_FIX (12.615),
-  SANE_FIX (220.0),		/* physical windowsize: 220 mm  */
-  SANE_FIX (297.0),		/* physical windowsize: 300 mm  */
-  SANE_FIX (1.0),
-  SANE_FIX (0.0),
+  {600, 300, 150, 75, 0},	/* possible x-resolutions */
+  {600, 300, 150, 75, 0},	/* possible y-resolutions */
+  {16, 12, 8, 0},		/* possible depths in gray mode */
+  {16, 12, 8, 0},		/* possible depths in color mode */
 
-  SANE_FIX (0.0),		/* no TA */
-  SANE_FIX (0.0),
-  SANE_FIX (100.0),
-  SANE_FIX (100.0),
-  SANE_FIX (0.0),		/* ld_shift */
+  SANE_FIX (6.519),		/* Start of scan area in mm  (x) */
+  SANE_FIX (12.615),		/* Start of scan area in mm (y) */
+  SANE_FIX (220.0),		/* Size of scan area in mm (x) */
+  SANE_FIX (297.0),		/* Size of scan area in mm (y) */
 
-  32, 16, 0,
-  0,
+  SANE_FIX (1.0),		/* Start of white strip in mm (y) */
+  SANE_FIX (0.0),		/* Start of black mark in mm (x) */
 
-  COLOR_ORDER_RGB,
-  {0x14, 0x07, 0x14, 0x07, 0x14, 0x07},
-  {0x157, 0x157, 0x157},
-  SANE_FALSE,
-  GT68XX_FLAG_UNTESTED
+  SANE_FIX (0.0),		/* Start of scan area in TA mode in mm (x) */
+  SANE_FIX (0.0),		/* Start of scan area in TA mode in mm (y) */
+  SANE_FIX (100.0),		/* Size of scan area in TA mode in mm (x) */
+  SANE_FIX (100.0),		/* Size of scan area in TA mode in mm (y) */
 
-  /* 50 dpi and 1200 dpi scan does not work (for lexmark x70); when using
-     automatic gain pictures are too dark. Only some ad hoc tests for
-     lexmark x70 were done so far. WARNING: Don't use the Full scan option
-     with the above settings, otherwise the sensor may bump at the end of
-     the sledge and the scanner may be damaged!  */
+  SANE_FIX (0.0),		/* Start of white strip in TA mode in mm (y) */
+
+  32, 16, 0,			/* RGB CCD Line-distance correction in pixel */
+  0,				/* CCD distcance for CCD with 6 lines) */
+
+  COLOR_ORDER_RGB,		/* Order of the CCD/CIS colors */
+  {0x14, 0x07, 0x14, 0x07, 0x14, 0x07},	/* Default offset/gain */
+  {0x157, 0x157, 0x157},	/* Default exposure parameters */
+  SANE_FIX (2.0),		/* Default gamma value */
+
+  SANE_FALSE,			/* Is this a CIS scanner? */
+  GT68XX_FLAG_UNTESTED		/* Which flags are needed for this scanner? */
+    /* When using automatic gain pictures are too dark. Only some ad hoc tests for
+       lexmark x70 were done so far. WARNING: Don't use the Full scan option
+       with the above settings, otherwise the sensor may bump at the end of
+       the sledge and the scanner may be damaged!  */
 };
 
 static GT68xx_Model plustek_op1248u_model = {
-  "plustek-op1248u",
-  "Plustek",
-  "OpticPro 1248U",
-  "ccd548.fw",
-  SANE_FALSE,
+  "plustek-op1248u",		/* Name */
+  "Plustek",			/* Device vendor string */
+  "OpticPro 1248U",		/* Device model name */
+  "ccd548.fw",			/* Name of the firmware file */
+  SANE_FALSE,			/* Dynamic allocation flag */
 
-  &plustek_gt6801_command_set,
+  &plustek_gt6801_command_set,	/* Command set used by this scanner */
 
-  600,	/* Optic X DPI           */
-  600,  /* Optic Y DPI           */
-  600,  /* Base X DPI            */
-  600,  /* Base Y DPI            */
-  600,  /* Y DPI force line mode */
+  600,				/* maximum optical sensor resolution */
+  600,				/* maximum motor resolution */
+  600,				/* base x-res used to calculate geometry */
+  600,				/* base y-res used to calculate geometry */
+  50,				/* if ydpi is equal or higher, use linemode */
+  SANE_TRUE,			/* Use base_ydpi for all resolutions */
 
-  SANE_TRUE,
-  {600, 300, 150, 75, 0},
-  {600, 300, 150, 75, 0},
+  {600, 300, 150, 75, 0},	/* possible x-resolutions */
+  {600, 300, 150, 75, 0},	/* possible y-resolutions */
+  {12, 8, 0},			/* possible depths in gray mode */
+  {12, 8, 0},			/* possible depths in color mode */
 
-  {12, 8, 0},
-  {12, 8, 0},
-  SANE_FIX (5.6),    	/* scanarea start X */
-  SANE_FIX (8.0),       /* scanarea start Y */
-  SANE_FIX (218.0),
-  SANE_FIX (299.0),
-  SANE_FIX (0.0),       /* shading start  */
-  SANE_FIX (0.0),		/* no black mark  */
-  SANE_FIX (0.0),		/* no TA */
-  SANE_FIX (0.0),
-  SANE_FIX (100.0),
-  SANE_FIX (100.0),
-  SANE_FIX (0.0),
+  SANE_FIX (5.6),		/* Start of scan area in mm  (x) */
+  SANE_FIX (7.5),		/* Start of scan area in mm (y) */
+  SANE_FIX (218.0),		/* Size of scan area in mm (x) */
+  SANE_FIX (299.0),		/* Size of scan area in mm (y) */
 
-  /* line distance correction */
-  0, 0, 0,
-  0,
+  SANE_FIX (0.0),		/* Start of white strip in mm (y) */
+  SANE_FIX (1.0),		/* Start of black mark in mm (x) */
 
-  COLOR_ORDER_BGR,
-  {31, 25, 31, 25, 31, 25},
-  {0x157, 0x157, 0x157},
-  SANE_FALSE,			/* is a CCD device */
-  0
+  SANE_FIX (0.0),		/* Start of scan area in TA mode in mm (x) */
+  SANE_FIX (0.0),		/* Start of scan area in TA mode in mm (y) */
+  SANE_FIX (100.0),		/* Size of scan area in TA mode in mm (x) */
+  SANE_FIX (100.0),		/* Size of scan area in TA mode in mm (y) */
+
+  SANE_FIX (0.0),		/* Start of white strip in TA mode in mm (y) */
+
+  0, 8, 16,			/* RGB CCD Line-distance correction in pixel */
+  0,				/* CCD distcance for CCD with 6 lines) */
+
+  COLOR_ORDER_BGR,		/* Order of the CCD/CIS colors */
+  {31, 25, 31, 25, 31, 25},	/* Default offset/gain */
+  {0x157, 0x157, 0x157},	/* Default exposure parameters */
+  SANE_FIX (2.0),		/* Default gamma value */
+
+  SANE_FALSE,			/* Is this a CIS scanner? */
+  GT68XX_FLAG_UNTESTED | GT68XX_FLAG_OFFSET_INV	/* Which flags are needed for this scanner? */
 };
 
 static GT68xx_USB_Device_Entry gt68xx_usb_device_list[] = {
@@ -663,10 +806,9 @@ static GT68xx_USB_Device_Entry gt68xx_usb_device_list[] = {
   {0x05d8, 0x4002, &mustek_scanexpress1200ubplus_model},	/* manual override */
   {0x05d8, 0x4002, &artec_ultima2000_model},	/* manual override */
   {0x05d8, 0x4002, &mustek_2400cu_model},	/* manual override */
+  {0x05d8, 0x4002, &mustek_scanexpress2400usb_model}, /* manual override */
   {0x055f, 0x0210, &mustek_a3usb_model},
   {0x043d, 0x002d, &lexmark_x73_model},
   {0x07b3, 0x0401, &plustek_op1248u_model},
   {0, 0, NULL}
 };
-
-/* vim: set sw=2 cino=>2se-1sn-1s{s^-1st0(0u0 smarttab expandtab: */
diff --git a/backend/gt68xx_high.c b/backend/gt68xx_high.c
index c3b6c857e..2a92f581e 100644
--- a/backend/gt68xx_high.c
+++ b/backend/gt68xx_high.c
@@ -920,6 +920,7 @@ struct GT68xx_Afe_Values
   SANE_Int max_width;
   SANE_Int scan_dpi;
   SANE_Fixed start_black;
+  SANE_Int offset_direction;
 };
 
 #ifndef NDEBUG
@@ -1037,9 +1038,9 @@ gt68xx_afe_ccd_adjust_channel_offset (GT68xx_Afe_Values * values,
   gt68xx_afe_ccd_calc (values, buffer);
   avg = (values->white + values->black) / 2;
   if (avg <= 122)
-    *offset -= off_dist;
+    *offset -= (off_dist * values->offset_direction);
   else if (avg >= 130)
-    *offset += off_dist;
+    *offset += (off_dist * values->offset_direction);
   DBG (5, "Offset: white=%d, black=%d, avg=%d, offset=%d\n",
        values->white, values->black, avg, *offset);
 }
@@ -1055,7 +1056,7 @@ gt68xx_afe_ccd_adjust_channel_white (GT68xx_Afe_Values * values,
   if ((values->white - values->black) < 230)
     {
       if (values->white > 253)
-	(*offset)++;
+	(*offset) += values->offset_direction;
       else
 	(*pga)++;
     }
@@ -1085,7 +1086,7 @@ gt68xx_afe_ccd_adjust_channel_black (GT68xx_Afe_Values * values,
       if (values->white > 250)
 	(*pga)--;
       else
-	(*offset)--;
+	(*offset) -= values->offset_direction;
     }
   else if (values->black < 15)	/* just right */
     {
@@ -1095,7 +1096,7 @@ gt68xx_afe_ccd_adjust_channel_black (GT68xx_Afe_Values * values,
 	done = 1;
     }
   else
-    (*offset)++;		/* too high */
+    (*offset) += values->offset_direction;	/* too high */
 
   DBG (5, "Black: white=%d, black=%d, offset=%d, pga=%d\n",
        values->white, values->black, *offset, *pga);
@@ -1133,6 +1134,10 @@ gt68xx_afe_ccd_auto (GT68xx_Scanner * scanner,
   afe->r_pga = afe->g_pga = afe->b_pga = 0x00;
   afe->r_offset = afe->g_offset = afe->b_offset = 0x20;
 
+  values.offset_direction = 1;
+  if (scanner->dev->model->flags & GT68XX_FLAG_OFFSET_INV)
+    values.offset_direction = -1;
+
   request.x0 = SANE_FIX (0.0);
   request.xs = scanner->dev->model->x_size;
   request.xdpi = 300;
@@ -1443,7 +1448,7 @@ gt68xx_afe_cis_calc_white (GT68xx_Afe_Values * values,
 static SANE_Bool
 gt68xx_afe_cis_adjust_offset (GT68xx_Afe_Values * values,
 			      unsigned int *black_buffer,
-			      SANE_Int offset_direction, SANE_Byte * offset)
+			      SANE_Byte * offset)
 {
   SANE_Int offs = 0, tmp_offset = *offset;
   SANE_Int low = 8, high = 22;
@@ -1451,16 +1456,16 @@ gt68xx_afe_cis_adjust_offset (GT68xx_Afe_Values * values,
   gt68xx_afe_cis_calc_black (values, black_buffer);
   if (values->black < low)
     {
-      offs = (offset_direction * (low - values->black) / 4);
+      offs = (values->offset_direction * (low - values->black) / 4);
       if (offs == 0)
-	offs = offset_direction;
+	offs = values->offset_direction;
       DBG (5, "black = %d (too low) --> offs = %d\n", values->black, offs);
     }
   else if (values->black > high)
     {
-      offs = -(offset_direction * (values->black - high) / 7);
+      offs = -(values->offset_direction * (values->black - high) / 7);
       if (offs == 0)
-	offs = -offset_direction;
+	offs = -values->offset_direction;
       DBG (5, "black = %d (too high) --> offs = %d\n", values->black, offs);
     }
   else
@@ -1635,7 +1640,6 @@ gt68xx_afe_cis_auto (GT68xx_Scanner * scanner)
   GT68xx_Afe_Values values;
   GT68xx_AFE_Parameters *afe = scanner->dev->afe;
   GT68xx_Exposure_Parameters *exposure = scanner->dev->exposure;
-  SANE_Int offset_direction;
   SANE_Int done;
   SANE_Bool first = SANE_TRUE;
   unsigned int *r_buffer = 0, *g_buffer = 0, *b_buffer = 0;
@@ -1655,13 +1659,12 @@ gt68xx_afe_cis_auto (GT68xx_Scanner * scanner)
     return SANE_STATUS_NO_MEM;
 
   total_count = 0;
-  /*  afe->r_pga = afe->g_pga = afe->b_pga = 0x06; */
   do
     {
       offset_count = 0;
-      offset_direction = 1;
+      values.offset_direction = 1;
       if (scanner->dev->model->flags & GT68XX_FLAG_OFFSET_INV)
-	offset_direction = -1;
+	values.offset_direction = -1;
       exposure->r_time = exposure->g_time = exposure->b_time = 0x157;
       do
 	{
@@ -1671,17 +1674,13 @@ gt68xx_afe_cis_auto (GT68xx_Scanner * scanner)
 	  /* read black line */
 	  RIE (gt68xx_afe_cis_read_lines (&values, scanner, SANE_FALSE, first,
 					  r_buffer, g_buffer, b_buffer));
-	  /*offset_direction /= 2; */
 
 	  done =
-	    gt68xx_afe_cis_adjust_offset (&values, r_buffer, offset_direction,
-					  &afe->r_offset);
+	    gt68xx_afe_cis_adjust_offset (&values, r_buffer, &afe->r_offset);
 	  done &=
-	    gt68xx_afe_cis_adjust_offset (&values, g_buffer, offset_direction,
-					  &afe->g_offset);
+	    gt68xx_afe_cis_adjust_offset (&values, g_buffer, &afe->g_offset);
 	  done &=
-	    gt68xx_afe_cis_adjust_offset (&values, b_buffer, offset_direction,
-					  &afe->b_offset);
+	    gt68xx_afe_cis_adjust_offset (&values, b_buffer, &afe->b_offset);
 
 	  offset_count++;
 	  total_count++;
diff --git a/backend/gt68xx_high.h b/backend/gt68xx_high.h
index 07ee042d0..96fee8f41 100644
--- a/backend/gt68xx_high.h
+++ b/backend/gt68xx_high.h
@@ -210,6 +210,7 @@ enum GT68xx_Option
   OPT_GAIN_B,
 
   OPT_ENHANCEMENT_GROUP,
+  OPT_GAMMA_VALUE,
   OPT_THRESHOLD,
 
   OPT_GEOMETRY_GROUP,
@@ -258,6 +259,7 @@ struct GT68xx_Scanner
   struct timeval lamp_on_time;		   /**< Time when the lamp was turned on */
   struct timeval start_time;		   /**< Time when the scan was started */
   SANE_Int bpp_list[5];			   /**< */
+  SANE_Int *gamma_table;                   /**< Gray gamma table */
 };
 
 
diff --git a/backend/gt68xx_low.c b/backend/gt68xx_low.c
index fe198cace..b32024327 100644
--- a/backend/gt68xx_low.c
+++ b/backend/gt68xx_low.c
@@ -412,6 +412,8 @@ gt68xx_device_activate (GT68xx_Device * dev)
 
   memcpy (dev->afe, &dev->model->afe_params, sizeof (*dev->afe));
   memcpy (dev->exposure, &dev->model->exposure, sizeof (*dev->exposure));
+  dev->gamma_value = dev->model->default_gamma_value;
+
   dev->active = SANE_TRUE;
 
   return SANE_STATUS_GOOD;
@@ -1032,22 +1034,22 @@ gt68xx_device_read_finish (GT68xx_Device * dev)
        (long) dev->read_bytes_left);
 
 #ifdef USE_FORK
-  if (dev->shm_channel)
-    {
-      shm_channel_free (dev->shm_channel);
-      dev->shm_channel = NULL;
-    }
-
   if (dev->reader_pid != 0)
     {
       int status;
-      usleep (100000);
+      /* usleep (100000);*/
       DBG (7, "gt68xx_device_read_finish: trying to kill reader process\n");
       kill (dev->reader_pid, SIGKILL);
       waitpid (dev->reader_pid, &status, 0);
       DBG (7, "gt68xx_device_read_finish: reader process killed\n");
       dev->reader_pid = 0;
     }
+  if (dev->shm_channel)
+    {
+      shm_channel_free (dev->shm_channel);
+      dev->shm_channel = NULL;
+    }
+
 #endif /* USE_FORK */
 
   free (dev->read_buffer);
diff --git a/backend/gt68xx_low.h b/backend/gt68xx_low.h
index 48335e46b..ee31667a2 100644
--- a/backend/gt68xx_low.h
+++ b/backend/gt68xx_low.h
@@ -436,39 +436,48 @@ struct GT68xx_Model
 
   GT68xx_Command_Set *command_set;
 
-  SANE_Int optical_xdpi;
-  SANE_Int optical_ydpi;
-  SANE_Int base_xdpi;
-  SANE_Int base_ydpi;
-  SANE_Int ydpi_force_line_mode;
-  SANE_Bool constant_ydpi;	/* Use base_ydpi for all resolutions */
-  SANE_Int xdpi_values[MAX_RESOLUTIONS];
-  SANE_Int ydpi_values[MAX_RESOLUTIONS];
-  SANE_Int bpp_gray_values[MAX_DPI];
-  SANE_Int bpp_color_values[MAX_DPI];
-  SANE_Fixed x_offset;		/* Start of scan area in mm */
-  SANE_Fixed y_offset;		/* Start of scan area in mm */
-  SANE_Fixed x_size;		/* Size of scan area in mm */
-  SANE_Fixed y_size;		/* Size of scan area in mm */
-  SANE_Fixed y_offset_calib;	/* Start of white strip in mm */
-  SANE_Fixed x_offset_mark;	/* Start of black mark in mm */
+  SANE_Int optical_xdpi;	/* maximum resolution in x-direction */	      
+  SANE_Int optical_ydpi;	/* maximum resolution in y-direction */	      
+  SANE_Int base_xdpi;		/* x-resolution used to calculate geometry */ 
+  SANE_Int base_ydpi;		/* y-resolution used to calculate geometry */ 
+  SANE_Int ydpi_force_line_mode;/* if ydpi is equal or higher, use linemode */
+  SANE_Bool constant_ydpi;	/* Use base_ydpi for all resolutions        */
 
+  SANE_Int xdpi_values[MAX_RESOLUTIONS]; /* possible x resolutions */	 
+  SANE_Int ydpi_values[MAX_RESOLUTIONS]; /* possible y resolutions */	 
+  SANE_Int bpp_gray_values[MAX_DPI]; /* possible depths in gray mode */	 
+  SANE_Int bpp_color_values[MAX_DPI]; /* possible depths in color mode */
+
+  SANE_Fixed x_offset;		/* Start of scan area in mm */		
+  SANE_Fixed y_offset;		/* Start of scan area in mm */		
+  SANE_Fixed x_size;		/* Size of scan area in mm */		
+  SANE_Fixed y_size;		/* Size of scan area in mm */		
+				                                        
+  SANE_Fixed y_offset_calib;	/* Start of white strip in mm */	
+  SANE_Fixed x_offset_mark;	/* Start of black mark in mm */		
+				                                        
   SANE_Fixed x_offset_ta;	/* Start of scan area in TA mode in mm */
   SANE_Fixed y_offset_ta;	/* Start of scan area in TA mode in mm */
   SANE_Fixed x_size_ta;		/* Size of scan area in TA mode in mm */
   SANE_Fixed y_size_ta;		/* Size of scan area in TA mode in mm */
+
   SANE_Fixed y_offset_calib_ta;	/* Start of white strip in TA mode in mm */
 
-  SANE_Int ld_shift_r;
-  SANE_Int ld_shift_g;
-  SANE_Int ld_shift_b;
-  SANE_Int ld_shift_double;
+  /* Line-distance correction (in pixel at optical_ydpi) for CCD scanners */
+  SANE_Int ld_shift_r; /* red */
+  SANE_Int ld_shift_g; /* green */
+  SANE_Int ld_shift_b; /* blue */
+  SANE_Int ld_shift_double; /* distance between two CCD lines of one color
+			       (only applicable for CCD with 6 lines) */
 
-  GT68xx_Color_Order line_mode_color_order;
-  GT68xx_AFE_Parameters afe_params;
-  GT68xx_Exposure_Parameters exposure;
+  GT68xx_Color_Order line_mode_color_order; /* Order of the CCD/CIS colors */
+
+  GT68xx_AFE_Parameters afe_params; /* Default offset/gain */
+  GT68xx_Exposure_Parameters exposure; /* Default exposure parameters */
+  SANE_Fixed default_gamma_value; /* Default gamma value */
 
   SANE_Bool is_cis;		/* Is this a CIS or CCD scanner? */
+
   SANE_Word flags;		/* Which hacks are needed for this scanner? */
   /*@} */
 };
@@ -492,6 +501,7 @@ struct GT68xx_Device
 
   GT68xx_AFE_Parameters *afe;
   GT68xx_Exposure_Parameters *exposure;
+  SANE_Fixed gamma_value;
 
   SANE_Bool read_active;
   SANE_Bool final_scan;
diff --git a/doc/descriptions/gt68xx.desc b/doc/descriptions/gt68xx.desc
index 1b8872eab..550aa1fda 100644
--- a/doc/descriptions/gt68xx.desc
+++ b/doc/descriptions/gt68xx.desc
@@ -1,6 +1,7 @@
 :backend "gt68xx"
 :status :beta
-:version "1.0-31"
+:version "1.0-32"
+:new :yes
 :manpage "sane-gt68xx"
 :url "http://www.meier-geinitz.de/sane/gt68xx-backend/"
 :comment "Only the USB scanners mentioned below are supported. For other Mustek BearPaws, look at the Plustek backend."
@@ -66,6 +67,10 @@
 :status :alpha
 :comment "Basically works but margins are not correct. More reports welcome."
 
+:model "ScanExpress 2400 USB"
+:interface "USB"
+:status :untested
+:comment "Should be detected but may need some more work in the code. Testers welcome."
 
 :mfg "Plustek"
 :url "http://www.plustek.de/"
@@ -76,6 +81,11 @@
 :status :alpha
 :comment "Works up to 600 dpi in gray mode, try disabling calibration"
 
+:model "OpticPro UT16B"
+:interface "USB"
+:status :untested
+:comment "Isn't detected yet mut may work some time in future. Testers welcome."
+
 :mfg "Artec"
 :url "http://www.artecusa.com/"
 
@@ -144,3 +154,11 @@
 :status :alpha
 :interface "USB"
 :comment "should work like the X70, but was reported to fail, more reports welcome"
+
+:mfg "Genius"
+:url "http://www.genius-kye.com/"
+
+:model "Colorpage Vivid3x"
+:status :untested
+:interface "USB"
+:comment "Not detected yet but should work when code is added"
diff --git a/doc/gt68xx/gt68xx.CHANGES b/doc/gt68xx/gt68xx.CHANGES
index a8b070f1d..036f726aa 100644
--- a/doc/gt68xx/gt68xx.CHANGES
+++ b/doc/gt68xx/gt68xx.CHANGES
@@ -1,3 +1,23 @@
+gt68xx.CHANGES -*-text-*-
+
+V 1.0-32 (2002-12-08)
+
+- "Coarse calibration for first scan only" is off by default now. As at least
+  CIS calibration is faster now, it doesn't seem to be necessary and produces
+  wrong images sometimes.
+- Added gamma table.
+- Setup gamma to 2.0 by default.
+- Fixed (hopefully) sigpipe when cancelling.
+- No geometry quantization anymore (not necessary). That should fix scanimage
+  warnings.
+- Plustek 1248U: do linemode for every resolution, fix color correction.
+- Set SANE_CAP_EMULATED for gamma value.
+- Added comments for every Model member in gt68xx_devices.
+- Added Plustek UT16B and Genius Vivid3x to .desc.
+- Added implementation for inverted offset for CCD scanners.
+- Added Mustek ScanExpress 2400 USB. Well, at least it's detected.
+- Added NEW marker to .desc.
+
 V 1.0-31 (2002-11-21)
 
 - Changed 150 to 200 dpi for Mustek BearPaw 2400 TA.
diff --git a/doc/sane-gt68xx.man b/doc/sane-gt68xx.man
index b3dc818b1..9ca11b518 100644
--- a/doc/sane-gt68xx.man
+++ b/doc/sane-gt68xx.man
@@ -37,6 +37,8 @@ Mustek ScanExpress A3 USB
 .br
 Mustek ScanExpress 1200 UB Plus
 .br
+Mustek ScanExpress 2400 USB
+.br
 Packard Bell Diamond 1200
 .br
 Plustek OpticPro 1248U