How To Specify Printing Color Against “On Screen” Viewing
RGB, CMYK, and Pantone
There are three common ways to specify color for use in traditional offset printing and for on screen viewing (like for web sites) and inkjet printing: RGB, CMYK and Pantone.
RGB is the language of web sites, PDFs and anything intended primarily for viewing on a computer screen. Each pixel in a web graphic can have a value ranging from 0-255 in each of the three channels (red, green, blue) for a total of 16.7 million colors.
RGB is often used as the specification for digital/scanned photos and also for printing to inkjet printers. In general, you can achieve brighter colors using RGB than you can with CMYK. Even though each pixel in a web graphic (such as a photo) has a fixed RGB value (such as “27,68,34” which is a forest green) that exact same RGB value will look different across different monitors and in different viewing conditions.
If you are trying to match what you see on your computer screen with what you get on your inkjet printer, then you might need to calibrate/profile your monitor and possibly even your printer.
You may also hear about different color spaces and ICC profiles, which are attempts to further control what happens with color. Digital cameras (by default anyway) and web browsers tend to use a color space known as sRGB (which is basically what your monitor is capable of showing you) while some recommend using Adobe RGB which has a larger gamut (it has more colors than sRGB) but your computer screen can’t necessarily show you all the colors in Adobe RGB so you won’t get the full benefit of those extra colors until you make a print.
Adobe Photoshop and its little brother, Elements are considered the gold standard for working with RGB images (also called raster/bitmap images).
So to summarize, if you are working on your computer on things intended for onscreen viewing or inkjet printing then you are probably working using the RGB color specification (although there’s no law against sending a CMYK file to these devices if that’s what you have to work with).
Offset printing (like taking business cards to a local professional printer) doesn’t work with RGB (if you send the printer an RGB file it will most likely be converted to CMYK). Instead, it uses a standard called CMYK (cyan, magenta, yellow, black).
Basically, all the colors can be produced using a combination of the four inks (in theory cyan, magenta and yellow mixed together should produce black but this is the real world where things aren’t perfect and so a fourth black ink had to be added for blacks and grays).
CMYK has a smaller gamut than RGB, which means that there are some colors you can specify in RGB (especially some of the popular bright ones) that don’t have a corresponding CMYK color (which can be an issue if your corporate identity starts out with a web site and then later on you do some offset printing). Adobe Illustrator/InDesign and Quark XPress are the gold standards for working with CMYK colors. Also with offset printing you tend to get into vector graphics (like with logos) that are very useful because they can be scaled up and down to whatever size is needed without significant loss of quality.
Printers talk about the number of colors in your job (and say things like 4/4 which means four color front and back, although in this case the term color really means an ink tank that goes on the printing press) and to do regular color photos in CMYK (in a brochure, for example) you will need a four-color job. Sometimes you see things like 5/5 which could mean the addition of a varnish or aqueous coating at the end of the run (and that counts like a fifth ink tank). You can do one, two or three-color jobs (typically to save money) but sometimes because they can look cool you can use spot colors for your job from the Pantone system which we’ll talk about next.
So to summarize, if you are doing the regular offset printing (without special spot colors) then CMYK is probably what you’ll be dealing with.
The gold standard for offset printing is the Pantone system (sometimes referred to as PMS) where a company named Pantone has specified more than 1000 solid colors and sells swatch books showing how those colors will print on coated, uncoated and matte white paper.
If your color is specified as saying “Pantone 574C” (the C means coated) then anyone with access to the Pantone swatch books can look that up and see that it’s a forest green. Printers can purchase special inks to match the Pantone colors or they can look up how best to convert that Pantone color specification into regular CMYK in cases where it’s not desirable/possible to use special Pantone inks (but in some cases there isn’t a precise match between Pantone and CMYK and some amount of color shifting will be experienced).
Some of the Pantone colors are ones that would be difficult to achieve using just CMYK alone (like Coca-Cola red). If you are doing an offset print job that includes regular color photos, then you will need four ink tanks (C, M, Y, K) for the photos and then if you add Pantone spot colors that will increase your cost somewhat. Or you can do what’s called a two-color job (which will cost less than a four-color job and possibly could be done with a smaller printer) with say black (K) and your Pantone 574C and then you can use tints of black and your Pantone color for free (and with color photos you can do what’s called duotoning where basically you make the photo b&w and then tint it with your chosen Pantone color).
Keep in mind that the Pantone swatch books only show how the color will look in the white paper that Pantone chose to use for their swatch books (so your actual results on your chosen paper, especially if non-white, may vary).
Also know that Pantone regularly updates their swatch books (typically to use brighter, whiter paper) and formulas so even though in theory Pantone 574C is a precise color specification in reality that specification may shift a bit over time and the final result you get may depend on which version of the Pantone swatch books the ink being used was made from.
So to summarize, Pantone is the gold standard for getting precise color with offset printing (and gives you some colors you couldn’t get with just CMYK alone) but even the Pantone system isn’t perfect and using Pantone could potentially add to your job cost if you are already doing regular color photos.
Final Bit of Advice
Ideally, when getting your corporate identity done (often when you get a logo) you will be given all three systems for your colors (so for each color you will get a Pantone solid/formula color , a CMYK value and an RGB value) keeping in mind that each system is different and it’s not always possible to have the color look exactly the same printed Pantone vs. CMYK vs. RGB (not to mention the fact that computer screens use a totally different technology from printers to begin with).
My advice to clients is that they’ll live longer if they’re willing to accept some amount of variation in their base colors across the different types of marketing pieces they’ll be doing overtime.
If you are choosing Pantone colors, then it pays to consider how those colors will look done in CMYK (and Pantone provides a “bridge” swatch book that shows how this works). If you are reviewing your corporate colors onscreen or via inkjet prints that may not be giving you a realistic impression of how your colors will look when printed CMYK/Pantone (for Pantone the printed Pantone swatch books are the gold standard of how the color will look when printed and you can have your printer do what’s called an ink drawdown to see how your Pantone color will look on a specific paper and for CMYK you might want to get what’s called a Digital Proof from a local offset printer since to some extent CMYK printing can make your colors a bit duller/muddier).
Even if you have Pantone specifications you will encounter some vendors that only do CMYK or RGB. Imagine different uses for your logo such as being embroidered on a hat, printed on a T-shirt or painted onto the front glass of your lobby (and each vendor that you use for that sort of thing will have their own particular way of doing things and some will support Pantone while others will do only CMYK or only RGB).