Photoshop seems to have a special mode for blending spot-color channels. Let's look at an example: blending full opacity red #ff3c1f with full opacity cyan #1cd4c6.

If I create two spot-color channels with solidity 0% and set their colors to #ff3c1f and #1cd4c6 and fill them with black I get #91550D:

spot color mixing

Now, I know that combining colors is a complex problem that's not even well-posed. But the result that photoshop gives gets very close to reality most of the time for me. Can anyone help me understand how photoshop does this blending?

I have read on the Adobe forums that it's multiplicative blending in CMYK. So I tried to reproduce that with layers, but I am getting #7D4339:

cmyk multiply blending

I know CMYK is device-dependent but I've tried lots of various profiles but none worked like the spot-color channels. The screenshot is from using the U.S. Web Coated (SWOP) v2 profile.

I tried Multiply blend in Lab and in RGB, but those were even further off.

I would really appreciate any insight on this whatsoever!

  • Hi the21st, welcome to GDSE and thanks for your question. If you want to know more about the site, please see the help center or ping one of us in Graphic Design Chat once your reputation is sufficient (20). Keep contributing and enjoy the site! – Zach Saucier May 15 '15 at 13:07
  • I don't understand what you are seeking here or what the question is. Why are you speaking of Pantone and CMYK but referencing colors with Hex (RGB)??? What's the goal here??? – Scott May 15 '15 at 15:21
  • @Scott I edited the question to not include any references to Pantone colors. The problem remains the same though. – the21st May 15 '15 at 19:28
  • 2
    You still haven't really described any "problem" which you're trying to solve. You've explained differences between spot blending and CMYK blending... but what exactly is the problem? Maybe I'm just not seeing it. Yes there's a difference. Why do you need to match blended spots with CMYK? Are you seeking to create a 2C piece which matches a 4C piece? Or are you merely wondering why there's a difference? – Scott May 15 '15 at 19:54
  • Spot colors are LAB in new photoshops. – joojaa May 16 '15 at 4:37

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