Pantone color conversions

Question

I am a bit of a newbie with using pantones and the pantone color guide. I am currently working on a branding project where we will have print material in both pantone and cmyk, and also on screen rgb colors. I would like these colours to match as closely as possible. I used the Pantone color Manager program to help me find the cmyk and rgb references from my chosen pantone colors.

My problem is that there seems to be large discrepancies between the colors when going from the pantone to cmyk to rgb. Here is an example, the grey pantone 431U is slightly blue which I like and of course want to preserve but when I use the cmyk reference it looks way more blue on screen when both of them are side by side.

I looked online for other convertors and I found other references that seem closer on screen then the one found in the Color Manager program. I am a bit confused and I would like to know the best way to achieve the right colors, as I won't be able to test print with the printer.

Thanks Fred

Answer 1

NOTE: This got way longer than I expected, and I purposely glossed over a LOT of detail. If you'd like me to elaborate, just ask.

PMS Colors - Absolutely brilliant when used as designed for pre-mixed spot color offset printing. You can be assured the color you saw in your Pantone book is very closely represented in your final printed piece.

The problem is, most people don't use PMS colors for actual extra-channel spot color printing. They abuse them in a "Hey, this color looks nice" way they were never intended for.

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CMYK - If you specify CMYK values in your document, you get whatever you get when it is printed. CMYK is device dependent, so just about every CMYK device will give you it's own version of that recipe.

For example, give a master chef and your mechanic a recipe for Coq Au Vin. Make sure they have the identical ingredients too. The two results are going to be different... unless your mechanic is also a master chef.

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RGB - Forget about it. You have ZERO control over the device that will display your color and the possibilities are endless.

Create a new RGB document and assign the sRGB color profile. Dump in your PMS color and convert it to RGB. Use those numbers and try and stop worrying because there is so little you can do about it

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Converting from PMS colors to CMYK - EVERYTHING IS A LIE. Every single conversion you find is at best an approximation. Even the official Pantone Color Bridge conversion numbers are all but useless for you, unless you are printing on the same stock, using the same inks, under the same conditions... As the Color Guide says on page ii:

"The screen tint percentages supplied are based on the printing conditions under which this guide was produced, as defined on page iii, and are intended as guidelines. If your workflow varies from ours, adjustments may be made to optimize the match."

Page iii then goes on to list the very stringent environment that most jobs are likely never, ever be printed under.

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So, what do you do? Not much you can do. If you're printing spots, aka PMS colors, then your document shouldn't be combining PMS and CMYK versions of the same color.

If you're printing CMYK, then the extra spot color channels are never in play, and you're at the mercy of your printer / master chef / mechanic.

If you're displaying RGB, then you will never ever have actual printed PMS and CMYK colors in the same display.

My suggestion? Build your color guide for the branding package using Pantone's suggested numbers for RGB and CMYK. Even though they may not be correct for your specific output, at least you have the 800 pound Pantone gorilla to rely on. You used standards, and that's a good thing.

Finally, if your CMYK printer (people, not device) does "Late Binding" color management, you will likely get the best PMS color matches from their devices. Their RIP software will try to figure how to squeeze faux PMS colors out their CMYK gamut.

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Follow up to user1324925less' comment. There are likely one of two things going on:

1. Out of Gamut - In general, the majority of the Pantone Matching System colors are out of gamut of CMYK devices. That means, no matter how hard you try, you will never, ever make a reasonable match in CMYK (just look at the Color Bridge for hundreds of examples). The CYMK color space just does not contain those colors. It's the equivalent of trying to count from 1 to potato.

2. You versus Them - The conversions for you are good because they are 'in gamut' and happening in your particular environment with your display, input and output profiles, your calibrated monitor, etc. When you get someone else's converted PMS colors, that happened in their particular environment which is very likely different from yours.

Either way, there will be very little you can do about. If somebody specs a PMS color, then by all intents they should be expecting to print an actual extra channel spot color, or be ready to accept the limitations of PMS conversions to CMYK.

The Pantone Matching System has become the de facto standard for "picking a color." Unfortunately, the vast majority of instances I see are abuses of PMS. People see this little booklet and think "Oh, that's the color right there!" Few realize that the color they picked is only going to happen under very tightly controlled circumstances.

Answer 2

Since spot color conversions out of almost every application, InDesign, Quark, Illustrator, Photoshop etc... are different when you convert them on the fly, it makes it really tough to manage. What we find is InDesign is always best.

Keep in mind, the end user, what do they want? They usually don't even know what a bridge book is. They are mostly expecting you to convert their spot colors to CMYK and have it print looking like the Pantone Solid Coated and Uncoated books not the Bridge books. So by popular client demand, our process is to make the spot look like the PANTONE Solid books.

Through our testing, we have found that InDesign converts best. We use basically a modified PDF Preset of Press Quality, we change fonts to fully embed by making font embedding area 0%. We also change right under the Preset (Standard) to PDF-X-1A:2001, Output tab, Convert to Destination (Preserve Numbers) and US Web Coated SWOP_v2. Even though we are a sheetfed only shop. Finally, Ink Manager in the Output tab, Select which spots are to be converted and mark them as CMYK, or if all are to be converted from spots, select All Spots to Process. We use the PDF Multi Page import Script to bring supplied PDFs from clients, PDFs from Quark, or any other application. Our clients have been happy with that.

However, you should be using InDesign since Quark is not helping anyone, from there, pick the spots you want according to a PANTONE Solid Book, Add them as your swatches, and edit them from Spot to CMYK. Then as long as you use a color managed Print shop, your contract proofs will look like the actual spot color not the Bridge version. From there the should be able to match the proofs on press, or you should find another printer immediately!!!!

Answer 3

EVERYTHING on screen is displayed as RGB. And I mean everything. If you want to be accurate you need the printed Pantone color bridge and color guides.

Answer 4

Pantone color conversion will be maddening. Some colors cannot be precisely achieved in RGB or CMYK. In my formula guide, there are two symbols used to denote compatibility (4 dots fot CMYK, 3 open circles for RGB).

According to my formula guide, 431U should be achievable in both RGB and CMYK.

You would think that would mean that the conversions will be the same for this color regardless of the converter being used, but that is not the case. There is even going to be discrepancy between Photoshop and Illustrator (CS5, at least).

Illustrator document:

CMYK: 11/1/0/64
RGB: #6A737B

Photoshop document:

CMYK: 60/49/42/12
RGB: #6C7179

So, which one do you go with? Scott's answer is correct: you want the Pantone Bridge if the conversion truly matters.

If you're just providing a proof that will eventually be printed as a Pantone color, then usually Photoshop's/Illustrator's/whatever's conversion will be sufficient. Monitor calibration differences will mean that your client is probably seeing a slightly different color anyway.

But if you're producing a branding guideline or something like that where consistency is very important, consult the Bridge.