Luminous Landscape Forum

Raw & Post Processing, Printing => Colour Management => Topic started by: Guigui on January 18, 2010, 06:14:54 am

Title: Windows clipboard colors problem
Post by: Guigui on January 18, 2010, 06:14:54 am
Hello,

When I press the print screen button in Windows Xp and paste the clipboard in a new document in photoshop, the RGB values change quite a bit.

For instance, the gray background of photoshop (128,128,128) becomes slightly yellowish (125,126,120) !

Can anyone give me a clue about what I'm doing wrong ? Thanks.

Here is an image to illustrate my problem :
(http://i50.tinypic.com/2h5lkwx.png)
Title: Windows clipboard colors problem
Post by: Jonathan Wienke on January 18, 2010, 07:23:14 am
Quote from: Guigui
Hello,

When I press the print screen button in Windows Xp and paste the clipboard in a new document in photoshop, the RGB values change quite a bit.

For instance, the gray background of photoshop (128,128,128) becomes slightly yellowish (125,126,120) !

Can anyone give me a clue about what I'm doing wrong ? Thanks.

Nothing, actually. Photoshop is color managed, which means that it doesn't give a s%#t about RGB numbers per se, it cares about the actual color those numbers represent. So it's NOT sending the monitor "128,128,128", it's sending your monitor "50% gray, as determined by your monitor profile". In your case, that happens to be 125,126,120.

In any color managed application, the RGB numbers sent to the monitor or printer or any other output device WILL NOT be the same as the RGB numbers contained in the image data, because no two devices will display the exact same color when sent RGB 103,205,229, for example. What color management does is ensure that the RGB numbers sent to an output device (whether monitor, printer, or whatever) represent the SAME COLORS as in the original image file. The actual RGB numbers sent to the device will depend on the profile for the device.
Title: Windows clipboard colors problem
Post by: Guigui on January 19, 2010, 05:44:29 am
Quote from: Jonathan Wienke
Nothing, actually. Photoshop is color managed, which means that it doesn't give a s%#t about RGB numbers per se, it cares about the actual color those numbers represent. So it's NOT sending the monitor "128,128,128", it's sending your monitor "50% gray, as determined by your monitor profile". In your case, that happens to be 125,126,120.

In any color managed application, the RGB numbers sent to the monitor or printer or any other output device WILL NOT be the same as the RGB numbers contained in the image data, because no two devices will display the exact same color when sent RGB 103,205,229, for example. What color management does is ensure that the RGB numbers sent to an output device (whether monitor, printer, or whatever) represent the SAME COLORS as in the original image file. The actual RGB numbers sent to the device will depend on the profile for the device.
That makes sense, I guess. Thanks Jonathan.
Title: Windows clipboard colors problem
Post by: Mussi_Spectraflow on January 26, 2010, 02:58:24 pm
Not sure how the color of the background is being handled, that might be more system level? But if you created a PS document with a gray fill and then took a screenshot of that, you should see the same gray assuming that the screenshot was tagged with the monitor's color profile. On the Mac(10.6) screen grabs are tagged with the monitor profile.
Title: Windows clipboard colors problem
Post by: Neuffy on January 26, 2010, 03:40:34 pm
Quote from: Jonathan Wienke
Nothing, actually. Photoshop is color managed, which means that it doesn't give a s%#t about RGB numbers per se, it cares about the actual color those numbers represent. So it's NOT sending the monitor "128,128,128", it's sending your monitor "50% gray, as determined by your monitor profile". In your case, that happens to be 125,126,120.

In any color managed application, the RGB numbers sent to the monitor or printer or any other output device WILL NOT be the same as the RGB numbers contained in the image data, because no two devices will display the exact same color when sent RGB 103,205,229, for example. What color management does is ensure that the RGB numbers sent to an output device (whether monitor, printer, or whatever) represent the SAME COLORS as in the original image file. The actual RGB numbers sent to the device will depend on the profile for the device.

Cool. So that means that hardware-calibrated monitors should have a completely linear output. The paste should match the original. Just tried it, and it does!