I have an image with a linear gradient overlay (banner image on this page EDF Energy - Our Campaigns. I have set the RGB colour in CS4 to R: 29 G: 31 B: 79. However, when I save the file for web the colour darkens slightly as you will see on the site. I want to colours of the background and edge of the banner image to match exactly. Does anyone know how to fix this?
Photoshop's default settings make matching RGB colours in images with colours in code near impossible. But, it's easy if you change a few settings. Here's what to do:
The most important point is the last one. Convert to sRGB destructively changes the colour profile of your image from the document profile to sRGB, altering the values of each pixel.
More detail can be found here: Colour management and UI design
Please note: The instructions above are for Photoshop CS6, but CS4 is very similar. Illustrator is very similar as well.