Views
505
Replies
8
Status
Closed
I think I found some inaccuracies in the 16 bit modes of Adobe Photoshop CS (8.0.1) Β and I am not talking about the internal use of Βonly’ 2^15 values which is the subject of many threads.
To reproduce my findings, do the following:
===========================================
Press F8 to open the Information panel.
In the Info panel choose "pixel" as the unit for coordinates Expand the Info panel to see the palette options and tick "show 16 bit values"
Create a new document with the following settings:
Width: 32768 Pixels
Height: 500 Pixels
Color mode: Greyscale, 16 bit OR RGB-color, 16 bit
In the Tools palette, select default colors for foreground & background (yields full black, resp. full white)
In the Tools palette, select the gradient tool and use it (by drawing a horizontal line from pixel coordinate (X=0) to (X=32768) – or as close as you manage to) to create a gradient from left to right. In the Tools palette, select the color sampler tool and inspect the gradient (choose a suitable magnification to be able to move the tool via your mouse with a 1 pixel resolution).
Strange things to see:
1) If you chose greyscale mode, then for most pixels, the values for the color components R, G, B are not identical – but should be on a greyscale picture. (If you chose RGB-color mode, then the the values for the color components R, G, B are identical – as expected.)
2) On the right and left rim of the picture we have the expected
values of (0,0,0) resp. (32768,32768,32768), but the gradient is NOT smooth. Instead, some horizontally neighbouring pixels do have the same RGB-values, then going further yet one more pixel the RGB values ‘jump’ to another value Β and we are not taking about a single skipped value, but in the order of six.
Hold the color picker tool over some random pixel in the image, remember the RGB value displayed and double-click on the pixel to make its color the new foreground color.
Move the color picker tool over the rectangle for the foreground color in the tools palette to verify that the new foreground color has the same RGB values as previously displayed.
Now create a new image in 16 bit greyscale mode or 16 bit color mode and use the fill-tool to fill it with the current foreground color.
Strange things to see:
The color in the newly created image is different from the current foreground color.
Please help and tell me what I am doing wrong, if Photoshop really behaves like this or if there is some workaround.
Cheers.
To reproduce my findings, do the following:
===========================================
Press F8 to open the Information panel.
In the Info panel choose "pixel" as the unit for coordinates Expand the Info panel to see the palette options and tick "show 16 bit values"
Create a new document with the following settings:
Width: 32768 Pixels
Height: 500 Pixels
Color mode: Greyscale, 16 bit OR RGB-color, 16 bit
In the Tools palette, select default colors for foreground & background (yields full black, resp. full white)
In the Tools palette, select the gradient tool and use it (by drawing a horizontal line from pixel coordinate (X=0) to (X=32768) – or as close as you manage to) to create a gradient from left to right. In the Tools palette, select the color sampler tool and inspect the gradient (choose a suitable magnification to be able to move the tool via your mouse with a 1 pixel resolution).
Strange things to see:
1) If you chose greyscale mode, then for most pixels, the values for the color components R, G, B are not identical – but should be on a greyscale picture. (If you chose RGB-color mode, then the the values for the color components R, G, B are identical – as expected.)
2) On the right and left rim of the picture we have the expected
values of (0,0,0) resp. (32768,32768,32768), but the gradient is NOT smooth. Instead, some horizontally neighbouring pixels do have the same RGB-values, then going further yet one more pixel the RGB values ‘jump’ to another value Β and we are not taking about a single skipped value, but in the order of six.
Hold the color picker tool over some random pixel in the image, remember the RGB value displayed and double-click on the pixel to make its color the new foreground color.
Move the color picker tool over the rectangle for the foreground color in the tools palette to verify that the new foreground color has the same RGB values as previously displayed.
Now create a new image in 16 bit greyscale mode or 16 bit color mode and use the fill-tool to fill it with the current foreground color.
Strange things to see:
The color in the newly created image is different from the current foreground color.
Please help and tell me what I am doing wrong, if Photoshop really behaves like this or if there is some workaround.
Cheers.
Master Retouching Hair
Learn how to rescue details, remove flyaways, add volume, and enhance the definition of hair in any photo. We break down every tool and technique in Photoshop to get picture-perfect hair, every time.
