Why RGB Color Goes Flat After Converting to CMYK

http://www.HiDefColor.com This VIDEO tutorial will explore the science of the conversion. Watch bright colors of RGB fall into the CMYK color space. RGB color is additive color theory. Red, green and blue light together create white, while when they are off they are black. CMYK is subtractive color theory. Cyan, magenta and yellow ink act as filters when light relects off paper. The inks absorb and reflect different colors to create the illusion of color. Cyan, magenta and yellow are the gray component colors of red, green and blue light respectively. The gray component color will make a primart color neutral when at equal values.

Category:

Film & Animation

Tags:

• RGB
• sRGB
• Adobe RGB
• CMYK
• GRACoL
• color
• profile
• Photoshop
• gamut
• convert
• press
• printing
• LAB
• management

[stubbornpuppet23]

Well, it seems we are on the same page here, so thanks for your assistance.

I'm all calibrated (monitor and adobe suite), so that's good.

The issue is just plain coming down to the blue in the physical, printed samples I have matches the CMYK on my monitor, but there just isn't a web-safe RGB that hits it right. I've trial and errored to a web-safe color that is probably close enough that noone will notice. If you look at 3:03 on your vid, that little tip of green-blue on top is about right.

[hidefcolor]

@stubbornpuppet23 isn't it interesting that you have a CMYK color that doesn't fit RGB!? i'm glad i was of assistance. good luck!

[stubbornpuppet23]

Never enough room in the comments for a real discussion, so I'm adding this: Would it play out to just work in the original CMYK profile, save the logos and icons as a JPG or PNG and just use them. On my screen, they look just right when I do that... but I don't want to assume that they'll look fine to everyone else.

Again, THANK YOU! You're the only person who's responded to this question at all in the multiple places I've asked.

[hidefcolor]

@stubbornpuppet23 once you've previewed your color, you can now convert your image to sRGB through the 'convert to profile' option under edit menu. when you convert to sRGB, you want to select sRGB in the 'destination' drop-down menu and make sure you're using the Adobe color engine and 'black point compensation' button is checked. you can adjust 'rendering intent' to see which one works best for re-mapping your out-of-gamut colors; relative works well. your monitor must be calibrated..

[stubbornpuppet23]

I actually haven't converted from anything. I just have a companies official color that is C-100, M-64, Y-0, B-23. I am trying to develop some web graphics, icons and logos to match and I just cannot get anything to match it. I have the CS4 Master Suite to work with. The original logo is U.S. Web Coated (SWOP) v2. So, is there an RGB color profile that I can use that will display that narrow band of the CMYK spectrum where the aforementioned color lives.

[hidefcolor]

@stubbornpuppet23 i created your cmyk values in photoshop and assigned the US Web Coated (SWOP) profile. i was able to get a match with the sRGB color profile. if you're making images for the web, this is the RGB color profile you should be working in. you can use Photoshop's 'proof setup' option under the 'view' menu. select 'sRGB' under device to simulate drop-down menu and make sure 'preview' button and 'black point compensation' is checked. this will give you a preview of color.

[hidefcolor]

@stubbornpuppet23 what RGB profile did you convert to from CMYK? what CMYK profile are you working in? the profiles are extremely important to manage the color transformation. this will get you the best match. keep in mind that when you are converting color that are out of gamut, the rendering intent is critical to get the color back into the destination gamut. you will want to use either 'perceptual' or 'relative colormetric' to get accurate color.

[stubbornpuppet23]

Thanks for the nice video, but I have a company logo that was designed to fall into that blue space where CMYK expands beyond RGB capabilities. It seems that no matter how hard I try to get a good color for the web (to match the blue I need), it is slightly too grey and flat. Any adjustments to try to increase the vividness of the color instantly causes it to go too purple or too green. The CMYK is 100,64,0,23. Any pointers on an RGB setting that will look right?