1 Reply Latest reply on Jun 22, 2014 10:36 PM by D Fosse

    CMYK to RGB conversion in photoshop

    Designer91

      Hi,

       

      I have synchronized my colour settings in bridge to be the same across all my Adobe software, it's currently on Europe Prepress 3 because that's what I've been taught is correct in Australia. I have a colour swatch of C:0 M:90 Y:15 K:0 and when I change the colour slider to RGB in photoshop is gives me the values: R:200 G:53 B:122 (not sure if this is a good way of converting the colours?)

      My initial swatch:

      Screen Shot 2014-06-21 at 7.50.25 pm.png

       

      When I key this exact RGB value online it gives me a much darker swatch:

      Screen Shot 2014-06-21 at 7.52.28 pm.png

       

      So using multiple cmyk to rgb  online converters (to compare) I key in my initial cmyk values and the rgb swatch it converts to is so much brighter and gives me the values R: 255 G:25 B:217

      Screen Shot 2014-06-21 at 7.55.14 pm.png

       

      I know I'm doing something wrong. I hope someone can help me with this!

      Thanks in advance!

        • 1. Re: CMYK to RGB conversion in photoshop
          D Fosse Adobe Community Professional & MVP

          This is about 1) different color spaces which will have different numbers for the same color, and 2) gamut limitations going from one space to another (some color spaces are bigger than others and can contain more saturated colors).

           

          "Europe Prepress 3" is just a preset. It sets Adobe RGB as working RGB, and FOGRA39 as working CMYK. When you go online, however, you'll most likely get numbers corresponding to sRGB and US Web Coated (SWOP) v2, because these are the Photoshop defaults (but have no particular significance beyond that). IOW there are no such things as "RGB" and "CMYK" - only specific RGB color spaces and specific CMYK color spaces.

           

          In different color spaces, such as sRGB vs. Adobe RGB, the same color is represented by different values. That's why you have to convert from one to the other.