Colour values not matching up

Hi Kelly M,

Rob Day is your man to help withstep by step day to day Pantone usage detail.

Using the PANTONE +Solid values is more sensible IMO, because the CMYK values Pantone give in Bridge libraries relate to who knows what CMYK print condition!

You should see the PANTONE+ Solid Coated swatches listed in the Color Picker in Adobe apps as standard I believe. 

When selecting a colour swatch in the Adobe Color Picker you'll see the relevant CMYK and RGB values too, as calculated by Adobe [based on your "color settings" RGB and CMYK default profiles - I mention that because you'll perhaps see a "!" at the end of the numbers, that "!" signifies that the original colour values are outside the gamut (colour range) of the destination colour space.  Nothing you can do about that other than choose a Pantone swatch that’s within gamut.

I hope this helps

neil barstow, colourmanagement.net :: adobe forum volunteer

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Hi

Dov Isaacs is right of course that Pantone solid libraries are defined as L*a*b* (Lab for short) colours.

"Spot colors are supposed to be used for specific colors typically realized via spot color inks, not as a shorthand for particular RGB or CMYK colors in some color space." hits the nail right on the head:

The original Pantone system is, essentially, a system of specially mixed "Pantone" inks added to a colour print run as "special" ink colours using an additional unit on the press. 

I wonder what your job is for?

Rob Day mentioned here that you're working in Illustrator's RGB mode and you mention HEX colour - maybe it's for Web? Pantone colours, and especially CMYK values are pretty much irrelevant in those circumstances

It looks like you are actually using a Pantone Bridge Library where the colours are listed in CMYK

Maybe as a first step, you'd be better off with the Pantone Solid library [rather than B ridge] as it's defined as Lab colour rather than CMYK (which I believe is where your confusion springs from)

I'll try explain a little about how colour management works with Lab, CMYK and RGB, as well as Pantone.

As a basis to all this, it's important to understand that the same numerical RGB or CMYK colour values set in different RGB and CMYK colour spaces produce different visual results.

[in colour management we use the Lab colour model as a reference to how colour will appear visually.

Note that Lab is a colour model (not a colour space), RGB or CMYK are also colour models.

BUT Lab differs inasmuch as whereas Lab colour numbers unequivocally define colour-

RGB or CMYK values must be associated with a colour space to define colour, with CMYK or RGB we have to include an ICC profile to define the colour space,

for example: "Adobe RGB" or Coated GRACoL 2006 (ISO 12647-2:2004) CMYK].

You seem to be expecting certain RGB/ HEX values from a Pantone reference, BUT the RGB/ HEX (or CMYK) values needed to produce the same "reference" colour will differ between colour spaces.

I we enter a Lab value (or Pantone Solid colour) in Adobe's imaging software, the resulting RGB or CMYK values are produced by a conversion and will differ depending on the RGB or CMKY colours pace you're working in. 

If using Pantone CMYK values from Bridge Libraries we need to know what CMYK colour space Pantone intended. The on-line guide to Pantone Bridge mentions 'coated paper' and 'G7 technology', so we could perhaps expect Coated GRACoL 2006 (ISO 12647-2:2004).icc to produce similar numbers.

Here's an example Pantone+ solid coated 3155C and sRGB

Lab 34 -39 -23 =

C 100!, M 36!, Y 42!, K 21!** in Coated GRACoL 2006 (ISO 12647-2:2004) 

which = R 0, G 96, B 116 sRGB.icc

** the ! mark here means that specific Pantone colour is beyond the capability of Coated GRACoL 2006 (ISO 12647-2:2004) printing, its out of gamut

Different RGB colour spaces (e.g. sRGB /Adobe RGB) will translate those CMYK colours differently. 

For example Pantone+ solid coated 3155C and Adobe RGB

34 -39 -23 = C 100!, M 36!, Y 42!, K 21! 

in Coated GRACoL 2006 (ISO 12647-2:2004)

which = R 0, G 96, B 115 AdobeRGB.icc***

***Do note that other original colours will exhibit far greater shifts in RGB values.

All this means you cannot expect certain RGB (or HEX) values when looking at a Pantone swatch unless you KNOW the RGB colour space Pantone intended.

For web, you'd be better off defining colour for exchange between users as, say sRGB.icc values or if it's a print job and you're in Europe, say, CoatedFOGRA39.icc CMYK (or ideally THE CORRECT icc profile for the printing process).

Or maybe if you need swatchbooks, use Pantone + Coated Lab for this, because as I described above, Lab unequivocally defines colour.

Are you actually printing? If you do work in RGB then when your document goes to print, of course, a CMYK conversion takes place and that has to use THE CORRECT icc profile for the printing process

a little background reading I hope might help: https://www.colourmanagement.net/advice/about-icc-colour-profiles/

I hope this helps

if so, please "like" my reply

thanks

neil barstow, colourmanagement.net :: adobe forum volunteer

[please do not use the reply button on a message within the thread, only use the blue reply button at the top of the page, this maintains chronological order]

Also, keep in mind Pantone now provides two different versions of their libraries. As Dov notes the PANTONE + Solid libraries are defined as Lab, but there are also the PANTONE+ Color Bridge libraries, which are defined as process CMYK. I think you are referring to the Bridge library, although the suffix for Coated Bridge colors would be CP.

Your capture is showing Photoshop’s color picker with the Bridge CMYK definition for 3155, but your document’s color mode is RGB, so the RGB value showing in the Picker is the color managed conversion from your current Color Settings’ Working CMYK Space profile to your document’s assigned RGB profile—sRGB in your case. And, because your document is in RGB mode, the Info panel shows the conversion back to CMYK from your document’s RGB space:

If I change my CMYK Working Space to US Sheetfed Coated from the default US Web Coated SWOP, and refill with the Bridge color, the RGB appearance of  CMYK 100|9|29|47 changes because of the new profile, and I get a new conversion to RGB:

If I wanted the Info Panel’s CMYK value to match the Pantone Bridge value, the color mode of my document would have to be CMYK:

Pantone spot colors are not defined as CMYK or RGB, but rather as device-independent LaB colors. What RGB or CMYK colors result from ICC color management conversion of LaB or a particular RGB or CMYK color space may be out-of-gammut.

Spot colors are supposed to be used for specific colors typically realized via spot color inks, not as a shorthand for particular RGB or CMYK colors in some color space.