Why does Pantone Color Book color differ so substantially from RGB values?

Again bumping up an older post...

"Currently I'm just concerned how different the 208C spot color looks when prepping for print when compared to the RGB values which I've been digitally sending to the client."

This is why you don't send them RGB to view on screen. Monitors are all different, even if they're calibrated. If you're printing a PMS spot color, this is what the chip books are for. You send them a color chip because that's what the printer will be matching. Tell them to view the chip near a window with some daylight coming in because again, if you look at colors under a calibrated light, they will look very different under a fluorescent office light or incandescent light.

The reason for replying here, is that with the new Pantone Connect software, the color values stated for color bridge is different than what is printed in the physical books. For example, the RGB and CMYK values in the printed color bridge book for PMS 646 CP is different than the RGB and CMYK values stated in Pantone Connect for 646 CP. Shouldn't they be the same? That's truly confusing. Are they different because they're based on the different lighting schemes? Seems they should state that somewhere.

Sorry to resurrect an old post, but Pantone has some notes on their site now that tell at least part of the answer.

"Please note that RGB & Hex/HTML values will differ between the PANTONE Color Finder and the PANTONE Color Bridge Guides due to different standards for print and digital use. For the PANTONE Color Bridge Guides we use the M1 lighting standard to align with industry standards for process printing. For the PANTONE Color Finder we use the M2 lighting standard to align with commonly used design software like Adobe Photoshop."

Pantone's physical color decks use a different RGB value than what their web interface provides because they're using two different lighting models to capture the same color and approximate it as RGB. Because M2 is apparently the standard for graphic design, the RGB given on the web matches the closest RGB approximation measured under M2. When M1 lighting is used (Pantone's preference for defining colors physically), the measurement yields the RGB approximation seen in the deck.

If you're working in print, and for whatever reason you're unable to define the color via the CMYK approximation, I'd use the deck's RGB. If you're working with primarily digital content, I'd expect that the web-provided values will more closely line up with the average human perception of that color.

If you're working in both? Hopefully you have the capability to set multiple colors on the media in question so that the final output is based on the right standard for the right context. Or you have the capability to use CIELab or something similar that can maintain one standard and translate to different contexts.

PMS colors (and transparencies) take up a lot of time get correct. The only real way to really understand it is to do it a few times. Good luck. Use press proofs. They will save you money in the long term.

"Currently I'm just concerned how different the 208C spot color looks when prepping for print when compared to the RGB values which I've been digitally sending to the client."

Understood. So if you want it to be the same you have different ways of ensuring that. The only thing that will show you what "prime" PMS color is, is the PMS book. If you want true color PMS on your monitor you are looking at investing around 10-12K from a color correction monitor.

That is why the press proof is always the best way to know if your printer can hit the color or not. He has the same book and will tweak the press to match as close as possible. All presses have different strength and weaknesses in their color gamuts. Cannon is well known for their reds but their greens suffer greatly. HP is known for their blues but has orange issues.

An easy way to think of this is that you are comparing an oil painting with a watercolor.

You are comparing generic apples with glossy pears.

The RGB and Web colors indicated might be similar – or not. I don't care. Unless you have a full-blown color calibrated system at work, you might see on your screen that actually discover that they are intended to represent the same. But a lot can go wrong, without serious setup for color calibration. And I'm not even touching on sRGB and CMYK print-outs...

So the RGB (or Lab*) values indicated by Pantone can be really precise, but their rendition on a user's screen is just an approximation anyway. Don't get too hung-up on this. Stay on the safe side and tell your client that the previewed colors on your and their screens and the final output might vary. A lot !

But there's a bigger difference.

Compare for example the difference between 208C and 208U, and the colors from your sample:

As you can see, your and my 208C versions are pretty much the same. I measured them in Photoshop and found a hardly noticeable difference (and that might be due to color compression to downsize the file). But the 208U is totally different ! Why ? Because Pantone offers a preview of how the exact same ink will look on Coated (glossy) and Uncoated paper ! So the RGB or Web values represent the color of the ink itself; as bright as is can get. The colorbook swatches are representing the 208 ink plus paper !

* Lab values are 'closer' to the inner workings of Adobe software in conjunction with color calibrating tools and conversions. Lab is also how our eyes scientifically perceive color as a whole: Luminance, with an a and b value. So that's why software like Illustrator and Adobe offer you the option to either state Pantone inks in their true Lab values, or properly ad generically converted RGB values.

"Currently I'm just concerned how different the 208C spot color looks when prepping for print when compared to the RGB values which I've been digitally sending to the client."

First, understand that if you are sending something digitally to the client, their monitor will not display that color as you see it because all monitors are different. (Think of a brand new light bulb compared to one that is about to burn out).

If color is of utmost importance, you should request an ink drawdown swatch from your print vendor. Another option is to share a color target to the vendor so they can formulate to your intended color.

The question is a simple one but boy is it a big one. I am a true believer that if you understand the reason, you can fix the problem. So here is the quickest rundown I can do.

RGB is seen as light rays shooting towards you. (think stained glass - clear bright color)

CMYK is seen as light rays reflecting off the surface. (think Mona Lisa - flat and intense color but not glowing)

RGB is a working format. (creation)

CMYK is a printing format. (production)

RGB has a larger color range (Gamut) than four-color CMYK processes. That means that not all RGB colors are reproducible by CMYK machines even if they have the best software algorithms for color reproduction.

Therefore some brainy science type guys developed chemical based inks to expand the color range (gamut) to be able to reproduce more of the colors (one reason).

But how do you add a PMS to a 4 color press?

You don't. It's simply technically impossible.

Digital Printing:

1. If you want the PMS color, the HP Indigo (although a nightmare to run) is an amazing color achiever. it runs 4 color (CMYK) and has 2 more channels that can be assigned PMS colors of your choosing (including white ink for clear or chrome materials).

2. If that is too pricey, you will have to go with the best available match. Each and every studio, printer, artist, I ALWAYS suggest getting a press proof (hard copy) made before printing. We charge $75 for it, but it is directly from the press so there is no question as to how the final print will look because it's in your hands.

To be continued... got a rush job.

chemistry.

Only if you have sRGB in use you will get the correct web values for any color but with any other profile you will get different values.