diff --git a/backend/genesys_gl124.cc b/backend/genesys_gl124.cc
index efdaa8885..b29e9b8f2 100644
--- a/backend/genesys_gl124.cc
+++ b/backend/genesys_gl124.cc
@@ -1154,7 +1154,7 @@ static void gl124_init_scan_regs(Genesys_Device* dev, const Genesys_Sensor& sens
   /*** prepares data reordering ***/
 
   /* words_per_line */
-    bytes_per_line = (session.optical_pixels * session.params.xres) / session.optical_resolution;
+    bytes_per_line = session.output_pixels;
   bytes_per_line = (bytes_per_line * session.params.channels * session.params.depth) / 8;
 
   /* since we don't have sheetfed scanners to handle,
@@ -1184,7 +1184,7 @@ static void gl124_init_scan_regs(Genesys_Device* dev, const Genesys_Sensor& sens
   dev->read_active = SANE_TRUE;
 
     dev->session = session;
-    dev->current_setup.pixels = (session.optical_pixels * session.params.xres) / session.optical_resolution;
+    dev->current_setup.pixels = session.output_pixels;
   DBG(DBG_info, "%s: current_setup.pixels=%d\n", __func__, dev->current_setup.pixels);
   dev->current_setup.lines = lincnt;
   dev->current_setup.exposure_time = exposure_time;
@@ -1265,7 +1265,7 @@ gl124_calculate_current_setup (Genesys_Device * dev, const Genesys_Sensor& senso
     lincnt = session.params.lines + max_shift + session.num_staggered_lines;
 
     dev->session = session;
-    dev->current_setup.pixels = (session.optical_pixels * session.params.xres) / sensor.optical_res;
+    dev->current_setup.pixels = session.output_pixels;
   DBG (DBG_info, "%s: current_setup.pixels=%d\n", __func__, dev->current_setup.pixels);
   dev->current_setup.lines = lincnt;
   dev->current_setup.exposure_time = exposure_time;
diff --git a/backend/genesys_gl646.cc b/backend/genesys_gl646.cc
index 6d1b04300..26fbf59f3 100644
--- a/backend/genesys_gl646.cc
+++ b/backend/genesys_gl646.cc
@@ -592,7 +592,7 @@ static void gl646_setup_registers(Genesys_Device* dev,
 
   /* words_per_line must be computed according to the scan's resolution */
   /* in fact, words_per_line _gives_ the actual scan resolution */
-    words_per_line = (((endx - startx) * session.output_resolution) / sensor.optical_res);
+    words_per_line = session.output_pixels;
     bpp = session.params.depth/8;
     if (session.params.depth == 1) {
       words_per_line = (words_per_line+7)/8 ;
@@ -790,7 +790,7 @@ static void gl646_setup_registers(Genesys_Device* dev,
   dev->read_active = SANE_TRUE;
 
     dev->session = session;
-    dev->current_setup.pixels = ((endx - startx) * session.output_resolution) / sensor.optical_res;
+    dev->current_setup.pixels = session.output_pixels;
   dev->current_setup.lines = linecnt;
     dev->current_setup.exposure_time = sensor.exposure_lperiod;
     dev->current_setup.xres = session.output_resolution;
diff --git a/backend/genesys_gl841.cc b/backend/genesys_gl841.cc
index c41dc64a6..122f8a30c 100644
--- a/backend/genesys_gl841.cc
+++ b/backend/genesys_gl841.cc
@@ -1929,7 +1929,7 @@ dummy \ scanned lines
   /*** prepares data reordering ***/
 
 /* words_per_line */
-    bytes_per_line = (session.optical_pixels * session.params.xres) / session.optical_resolution;
+    bytes_per_line = session.output_pixels;
     bytes_per_line = (bytes_per_line *  session.params.channels * session.params.depth) / 8;
 
   requested_buffer_size = 8 * bytes_per_line;
@@ -1960,7 +1960,7 @@ dummy \ scanned lines
   dev->read_active = SANE_TRUE;
 
     dev->session = session;
-    dev->current_setup.pixels = (session.optical_pixels * session.params.xres) / session.optical_resolution;
+    dev->current_setup.pixels = session.output_pixels;
   dev->current_setup.lines = lincnt;
   dev->current_setup.exposure_time = exposure_time;
     dev->current_setup.xres = session.params.xres;
@@ -2099,7 +2099,7 @@ dummy \ scanned lines
     lincnt = session.params.lines + max_shift + session.num_staggered_lines;
 
     dev->session = session;
-    dev->current_setup.pixels = (session.optical_pixels * session.params.xres) / session.optical_resolution;
+    dev->current_setup.pixels = session.output_pixels;
   dev->current_setup.lines = lincnt;
   dev->current_setup.exposure_time = exposure_time;
     dev->current_setup.xres = session.params.xres;
diff --git a/backend/genesys_gl843.cc b/backend/genesys_gl843.cc
index f418cf400..008d784cd 100644
--- a/backend/genesys_gl843.cc
+++ b/backend/genesys_gl843.cc
@@ -1193,12 +1193,6 @@ static void gl843_compute_session(Genesys_Device* dev, ScanSession& s,
     // compute optical and output resolutions
     s.hwdpi_divisor = sensor.get_hwdpi_divisor_for_dpi(s.params.xres);
 
-    // after all adjustments on the optical pixels have been made, compute the number of pixels
-    // to retrieve from the chip
-    s.output_pixels = (s.optical_pixels * s.output_resolution) / s.optical_resolution;
-
-
-
     s.max_color_shift_lines = sanei_genesys_compute_max_shift(dev, s.params.channels,
                                                               s.params.yres, s.params.flags);
 
@@ -1450,7 +1444,7 @@ gl843_calculate_current_setup(Genesys_Device * dev, const Genesys_Sensor& sensor
     lincnt = session.params.lines + max_shift + session.num_staggered_lines;
 
     dev->session = session;
-    dev->current_setup.pixels = (session.optical_pixels * session.params.xres) / session.optical_resolution;
+    dev->current_setup.pixels = session.output_pixels;
   DBG(DBG_info, "%s: current_setup.pixels=%d\n", __func__, dev->current_setup.pixels);
   dev->current_setup.lines = lincnt;
   dev->current_setup.exposure_time = exposure;
diff --git a/backend/genesys_gl846.cc b/backend/genesys_gl846.cc
index 6459950c1..c6b0faa49 100644
--- a/backend/genesys_gl846.cc
+++ b/backend/genesys_gl846.cc
@@ -1034,7 +1034,7 @@ static void gl846_init_scan_regs(Genesys_Device* dev, const Genesys_Sensor& sens
   /*** prepares data reordering ***/
 
 /* words_per_line */
-    bytes_per_line = (session.optical_pixels * session.params.xres) / session.optical_resolution;
+    bytes_per_line = session.output_pixels;
     bytes_per_line = (bytes_per_line * session.params.channels * session.params.depth) / 8;
 
   requested_buffer_size = 8 * bytes_per_line;
@@ -1061,7 +1061,7 @@ static void gl846_init_scan_regs(Genesys_Device* dev, const Genesys_Sensor& sens
   dev->read_active = SANE_TRUE;
 
     dev->session = session;
-    dev->current_setup.pixels = (session.optical_pixels * session.params.xres) / session.optical_resolution;
+    dev->current_setup.pixels = session.output_pixels;
   dev->current_setup.lines = lincnt;
   dev->current_setup.exposure_time = exposure_time;
     dev->current_setup.xres = session.params.xres;
@@ -1159,7 +1159,7 @@ gl846_calculate_current_setup(Genesys_Device * dev, const Genesys_Sensor& sensor
     lincnt = session.params.lines + max_shift + session.num_staggered_lines;
 
     dev->session = session;
-    dev->current_setup.pixels = (session.optical_pixels * session.params.xres) / sensor.optical_res;
+    dev->current_setup.pixels = session.output_pixels;
   dev->current_setup.lines = lincnt;
   dev->current_setup.exposure_time = exposure_time;
     dev->current_setup.xres = session.params.xres;
diff --git a/backend/genesys_gl847.cc b/backend/genesys_gl847.cc
index f8bd06c75..0623081fc 100644
--- a/backend/genesys_gl847.cc
+++ b/backend/genesys_gl847.cc
@@ -1052,7 +1052,7 @@ static void gl847_init_scan_regs(Genesys_Device* dev, const Genesys_Sensor& sens
   /*** prepares data reordering ***/
 
 /* words_per_line */
-    bytes_per_line = (session.optical_pixels * session.params.xres) / session.optical_resolution;
+    bytes_per_line = session.output_pixels;
     bytes_per_line = (bytes_per_line * session.params.channels * session.params.depth) / 8;
 
   requested_buffer_size = 8 * bytes_per_line;
@@ -1079,7 +1079,7 @@ static void gl847_init_scan_regs(Genesys_Device* dev, const Genesys_Sensor& sens
   dev->read_active = SANE_TRUE;
 
     dev->session = session;
-    dev->current_setup.pixels = (session.optical_pixels * session.params.xres) / session.optical_resolution;
+    dev->current_setup.pixels = session.output_pixels;
   dev->current_setup.lines = lincnt;
   dev->current_setup.exposure_time = exposure_time;
     dev->current_setup.xres = session.params.xres;
@@ -1177,7 +1177,7 @@ gl847_calculate_current_setup(Genesys_Device * dev, const Genesys_Sensor& sensor
     lincnt = session.params.lines + max_shift + session.num_staggered_lines;
 
     dev->session = session;
-    dev->current_setup.pixels = (session.optical_pixels * session.params.xres) / sensor.optical_res;
+    dev->current_setup.pixels = session.output_pixels;
   dev->current_setup.lines = lincnt;
   dev->current_setup.exposure_time = exposure_time;
     dev->current_setup.xres = session.params.xres;
diff --git a/backend/genesys_low.cc b/backend/genesys_low.cc
index 46b41bc59..26ffbdbf1 100644
--- a/backend/genesys_low.cc
+++ b/backend/genesys_low.cc
@@ -1180,7 +1180,9 @@ void compute_session(Genesys_Device* dev, ScanSession& s, const Genesys_Sensor&
         s.optical_pixels = align_int_up(s.optical_pixels, 2 * s.ccd_size_divisor);
     }
 
-    // TODO output_pixels
+    // after all adjustments on the optical pixels have been made, compute the number of pixels
+    // to retrieve from the chip
+    s.output_pixels = (s.optical_pixels * s.output_resolution) / s.optical_resolution;
 
     // Note: staggering is not applied for calibration. Staggering starts at 2400 dpi
     s.num_staggered_lines = 0;
diff --git a/backend/genesys_settings.h b/backend/genesys_settings.h
index c26196222..e0c01ce9a 100644
--- a/backend/genesys_settings.h
+++ b/backend/genesys_settings.h
@@ -239,7 +239,6 @@ struct ScanSession {
     unsigned output_resolution = 0;
 
     // the number of pixels in output data
-    // gl843-only
     unsigned output_pixels = 0;
 
     // the number of bytes in the output of a single line