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I have a strange problem with Illustrator. The company I am working with has a stock hex colour - #0074aa (1).

According to online conversion sites, this hex code translates to the CMYK of:

C:  100
M:  31.6
Y:  0
K:  33.4

When I add these CMYK values to Illustrator as a colour swatch, these translate to a slightly darker, deeper blue (2). Alternatively if I add a swatch with the Hex value of #0074aa, the CMYK values are completely different.

Confusingly, if I put the translated CMYK values that Illustrator came up with after entering #0074aa into an online converter, the resulting hex match is completely different - a bright cyan blue (3)!

Does anyone have an idea as to why this is occurring? When I sent a business card design I made to the printer, the colour printed out was the bright cyan; hence why I am trying to figure out the reason for this problem.

I send my files to the printer by PDF. I'm working in CMYK mode in Illustrator CS5. Viewing the CMYK on iPhone also shows the bright cyan colour.

Colour differences

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1 Answer 1

This is not strange at all. It's one of the rudiments of digital color.

The glaring omissions in your data are the color profile the hex value is presented in and the color profile that the CMYK numbers are presented in.

"Translate to CMYK" is meaningless unless you know the color profile you're starting with and the CMYK color profile you are targeting. In fact, using "online conversion sites" when you have the best in the industry built into your software is like buying a car from Fast Eddie's Used Cars and Chinese Laundry when you have a Lexus parked in your driveway.

Numbers are just numbers. They don't represent colors, they map to colors in a specific color profile.

You need to do the following exercise for yourself to really internalize the point. It's quickest and easiest to demonstrate in Photoshop:

  • Open Photoshop and a new blank Photoshop default document.

  • Open Edit > Assign Profile and make it sRGB if it's not already. Close the dialog.

  • Make a patch of #0074aa in one corner.

  • Edit > Convert to Profile and choose Adobe RGB. Be sure that the conversion Intent is set to "Perceptual" or "Relative Colorimetric".

  • Use the eyedropper to find out what the hex value is of the patch you just made.

  • Make a new patch of #0074aa below the first one.

  • Edit > Convert to Profile and choose Coated GRACoL 2006.

  • Use the eyedropper to find out what the hex value is of the patch you just made.

  • Make another new patch of #0074aa.

  • Repeat for Web Coated SWOP v2 a couple more CMYK profiles, each time checking the hex value of the patch you made just before converting.

You now understand why #0074aa is completely useless number unless you know what color profile it represents.

This is a rock-bottom basic of print production that, frankly, you had no excuse not to be aware of if you're being paid for design work. Be glad it was a $50 print job you can compensate easily and not a $50k one that would get you fired or sued or both.

Buy a copy of Claudia McCue's excellent Real World Print Production and spend some quality time with it. It covers all the important things you should know before you venture anywhere near a print job again.

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