I'm in the process of starting a new company, and am trying to create the brand guideline document, so I'm having to learn all about RGB, CMYK, and Pantone from scratch, so apologies if this is a stupid question.

I'm using a document from an existing company as guidance for creating my own document, and my main issue is that the colors given for RGB/CMYK/Hex don't match what Pantone suggest.

Unfortunately I don't have a color bridge book, and am instead using the site; http://rgb.to/pantone/coated as reference.

According to the document I have, the main color is defined using the following figures;

  • Pantone 303
  • Hex 003145
  • RGB 0/49/69
  • CMYK 100/15/0/80
  • RAL 5011

Now according to the above link, the figures should be:

  • Hex 002a3a
  • RGB 0/42/58
  • CMYK 100/47/22/82

Is there any particular reason why these figures would not match?

Why would a Pantone color be specified if the conversion provided by Pantone is not being used?


2 Answers 2


I'll try to answer with some generalities first, because the background info seems like it would help in this case.

PANTONE matching ink colors can't be converted perfectly to RGB or CMYK, but there's more than one reason why that is.

RGB as you probably know, applies only to light, and making colors from the three light primaries: Red, Green and Blue. The RGB gamut (full range of possible colors) is wider than for printed ink colors.

Commercial Process color printing uses CMYK inks, and the gamut is narrower than for RGB. Some RGB colors really can't be reproduced in CMYK. Some Pantone inks really can't be reproduced exactly with CMYK process inks either.

In general, I would use Pantone's own specs for RGB or CMYK conversion, but keeping the gamut mismatches in mind.

Matching printed colors is an art and science. The only way to get somewhat consistent results is to use a color guide printed on the same stock, with the same process (web offset, for example), and same screen frequency. The bright red you get from 100M 100Y is going to look very different on newsprint versus glossy coated brilliant white stock.

Also, using CMYK values in software for a color that is only going to be displayed in RGB (in case that happens) doesn't make any sense -- the on screen display is an approximation of an approximation.

About your specific color: The 100-15-0-80 in CMYK looks lighter and more teal on my screen, but might be right for printing. But there would be no way to know without a matchprint (a calibrated proof made with CMYK colors). The 100-47-22-82 mix looks darker on screen, closer to the RGB 0-49-69, but again, the only way to tell is with a matchprint.

The second RGB spec -- 0-42-58 -- seems greener and yellower.

So, finally, keep in mind that there are many algorithms that are used in software to try to convert from one color system to another. None are exact, and different algorithms can produce different results. But the real thing to keep in mind is that, when going from an onscreen color to a printed color, (almost) all bets are off without actual, calibrated testing on the exact paper stock to be used.

BTW, that is a dark, subtle color you're working with, and it's probably going to look more greenish or blueish from one monitor to another, just using the same RGB values. The only way to get accurate printed results for a Pantone color swatch is to use actual PANTONE ink formulations, and to print them as spot (not process) colors.


The difference in color conversion can happen when you use some online conversion service.

Another possibility: the designer who prepared your files (since you seem to imply there's a color guideline) may have modified the color slightly. If you notice the CMYK recipe is way more "printer friendly" and frank than the conversion, and that color on coated stock is a very dark blue, almost black. The CMYK recipe you were given is more dark blue than a rich-black with blue.

According to Pantone, the value of 303C is:

RGB : 0-42-58


CMYK: C100-M47-Y22-K82


But as you can see below, all the different recipes are visibly different!

So what you have left is: choice! You choose which version you prefer and you stick to it.

pantone 303 examples

My preference is to convert directly my Pantone from Photoshop from pantone to CMYK to RGB, in that order ideally. It's way easier to start from a CMYK or a Pantone and then convert to a HEX/RGB value than the other way around. (See one way to do this here: Mismatched CMYK Values)

My version is the one on top. The version below is using the values from the Pantone website. You can see their CMYK value (middle of second row) has more magenta and is darker.

If it's not a big deal for you, you can use the values suggested by Pantone. That blue is still closer than the CMYK recipe you were given with your logo (that CMYK 100/15/0/80 looks more like a Pantone 548C actually.)

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