Color, Printing, and Color Matching

Color output has always been a constant trial and error process for me. With, every ambitious printing job, I am always learning how much I really don’t know, especially after I began painting and refining my color sensibility in art and design classes and later in my design career. To quote Aristotle, the more I know what I think I know about the practical aspects of color, the more I know I don’t know and that I needed to learn. Consistently, one of the biggest mysteries has been this elusive thing called the Pantone® Swatch. Oh sure, I could choose a book Coated or Non-coated, look at what I wanted to match, loosely thinking of how I would use the color, and find a swatch that I wanted. Nothing to it right? Right. In fact I don’t have to do that, ill just let the computer and printer do it for me. Right?

The first time I met the Pantone® matching system was when I worked at the "College Press" a print-shop in college. I worked there for about a year and after that moved onto design the college magazine. I was pretty adept at Photoshop at the time and it was there that I became acquainted with Adobe Indesign and making real use of Illustrator. While at the college press, I also worked as a pressman’s assistant and sort of got the hang of working with a one-color press and mixing inks and cleaning the press between each job. We had to mix some of these colors ourselves, before we started the press. That’s where the Pantone® books came in. First, let’s refresh ourselves on the printing process.

Printing as you probably know it

If you own a computer printer at home or in your office, and you have ever had to change those cartridges (They over charge. They don’t last long. It’s a scam. I know.) You can see that they come in 4 colors: cyan, magenta, yellow, and black inks. Theoretically if printing upon a white substrate like our printer paper usually is, any colors can be decently achieved with these four inks. This is called CMYK, 4-color, or “process” printing. The “K” isn’t k because black is spelled b-l-a-c-K. K refers to the “Key” which was what the offset printers back-in-the-day called the plate that handled black. Cyan plus magenta equals blue, magenta plus yellow equals red, and on and on. The color range that CMYK, or any color mixing standard, is able to create within is called the “gamut.”

(Side note: some printers add extra inks to the standard CMYK — most commonly a light cyan and a light magenta, but sometimes others — for better color reproduction, especially in photos. If you’re serious about home printing, a 6 or 8 color printer, with a equally serious manual to go along with it, might be an investment worth considering)

Regardless, there is a limit to the precision of process printing. Even the best process printers are mixing inks on the fly to create a limited range of color, and that can often result in inconsistency. 

What do we mean when we call it a Spot Color?

That’s where the Pantone® Matching System, called just Pantone® or PMS for short, comes in. Pantone® inks are special inks that are each created prior to printing. Inks such as this are called “spot” colors. They aren’t combinations of cyan, magenta, yellow and/or black and aren’t created during printing; They’re precisely and individually mixed beforehand, kind of like paint. In many cases they actually incorporate opaque pigments such as Titanium for white which would technically make them a paint really. Spot colors are also like paint in that they are laid down by the printer in a flat uniform layer, as opposed to the tiny halftone dots created by 4 Color Process or CMYK. This makes spot colors much, much more consistent than process color. 

Think about it this way: if you were going to paint a wall in your house green, which would create a more consistent result? Buying a bucket of cyan and a bucket of yellow and mixing them together as you went, or just buying green paint to begin with? The latter, obviously. That’s why spot colors are so great. There are drawbacks to spot color printing, however. Spot colors each require their own ink well during printing.

Let’s say you have a project that you want to print in standard CMYK, except that your client wants their two-color logo printed with the two appropriate spot colors. That would make this a six-color job; cyan, magenta, yellow and black plus the two specified spot colors equals six. So unless your home or office printer has two extra spots for ink (and it almost certainly doesn’t), this unfortunately means that the job will need to be handled by a professional print shop. This won’t be cheap!

The most common usage of spot colors that I have used come in the form of jobs sent to a professional printer that use less than 2 colors since professional print shops usually charge by plate. This would save money. On the other hand, if we are printing on a stock other than white, and we need to produce a tone lighter than the stock itself, aluminum or clear labels for instance, spot white would be used to create an opaque layer behind the process printed areas.

To summarize, besides pushing the gamut beyond the limitations of your substrate, spot color printing is the best way to ensure color accuracy and a high-quality print, but because of its nature, it’s difficult and often expensive. Even large companies usually reserve spot color printing only for the most important printed materials, or those that only require one or maybe two colors.

Pantone® is more than just spot inks. It’s the Pantone Matching System (PMS)

Well, you probably can’t print actual Pantone inks on your own, but there’s good news: Each Pantone swatch in the book includes CMYK, RGB and HTML values to reproduce that swatch color as accurately as possible in standard print and onscreen applications.

These Pantone guys are good. It’s the industry standard! They have effectively achieved a monopoly on the color matching industry today. They provide the definitive way to reproduce a color. They take out the middle man in the form of digital hardware and software which brings a whole n’other margin of error into the mix. Unless you or your client are actually shelling out the money to print spot inks, the best way to reproduce those glorious Pantone swatches as accurately as possible is to replace every spot color swatch in your document with its appropriate Pantone-recommended CMYK swatch, found in the Pantone swatch books. There are online resources to locate these values as well, but they may not always be 100% accurate. They also recommend that professionals replace each swatch book once a year or every few years because of the fading. That’s how detailed they are.

Why must you use this book to convert the colors between mixing standards?

Spot color swatches in a design program aren’t meant to be printed correctly by a process printer which, by default, has four ink wells and can’t be switched out for other colors. When sent to the printer from your design program, they’re meant to register with the printer as the proper spot color. In other words, the input doesn’t match the output.

As shown in the image above, standard color swatches (such as the “Cornflower Blue” swatch) are indicated in the InDesign swatch panel by a checkered box icon to the right of the swatch name. Spot color swatches (like Pantone swatches) are indicated with a small dot icon in the same position. If you are using any spot color swatches in your document and you are not going to be printing those with true spot color inks, you must convert those spot color swatches and all instances of those colors in your document to standard CMYK values for best results.

Heres what happens otherwise:

If you send a document with spot colors to a process printer, the machine will check to see if it has spot color inks loaded up. When that check comes back negative, rather than just ignoring those colors in your document, it will automatically attempt to translate your spot colors into some combination of cyan, magenta, yellow and black ink. This is asking for trouble. Don’t ask a machine to do (a man's work) the work of an artist's trained eye especially if it wasn’t made for the job. Most people that don’t know this information would assume their printer was broken if they couldn’t print if sent a job so the manufacturers did pretty much the minimum in order to make their hardware able interpret all jobs coming from the printer as printable.

In the print popup window, select “output” on the left and see how many inks are in the ink section. If it’s more than the basic four process inks, you’ll want to convert your spot colors to process colors for optimal print results.

If you want something done right, you’ve got to do it yourself. This is where I went wrong as a student and as a rookie professional.

So we’ve established that we need to change our spot colors to process colors before we send our document to print. But that’s easy, right? Just switch the color panel to CMYK sliders and copy whatever values are there. They should be the same values as what’s listed in the Pantone swatch book, right? Why would they not? Adobe never compromises nor does anything wrong! Epson, and all the major printer manufacturers are perfect and rightfully successful and their expertise must not be questioned! That’s what I thought, too. This is wrong. We have a long way to go to reach this perfection and by then, something new will crop up and it will all go to hell all over again like when digital became a thing.

Here’s the color panel with a Pantone swatch selected.

If you open the panel menu and change the color to CMYK…

…you will not end up with the correct CMYK values for your Pantone swatch.

Changing the document color mode and/or the color mode in the color panel of a design program will NOT change a spot color to theappropriate CMYK, RGB or HTML value. You must get those from thePantone swatch book and enter them manually. (There are easyways to do this using the tools in the swatch panel, but I won’t go into thathere.) If you need help and are sending your work to a professional printer,express this to your concerns before they produce a proof, they will likelywork for you and color match according to instructions.

Take the example in the above image: the recommended CMYK formula for Pantone 285 Cis 90/48/0/0. That’s very far from the values that InDesign dialed up for me in the color panel in the screenshot before that. (A telltale sign of improperly converted CMYK swatches is that they involve decimal points, e.g., the 91.35% cyan shown in the color panel screenshot above. No Pantone swatch’s recommended CMYK value ever calls for decimals.)

Coated or Uncoated?

You may have noticed every Pantone swatch has a suffix, usually either “C” or “U” (though there are others). These two initials stand for coated and uncoated, respectively, and indicate the type of paper for which the swatch is best suited.

You may have also noticed that in general, when you print something on uncoated paper, say for example cheap office copy paper, or that artsy craftsy paper, your colors and images tend to come out darker than they do when you use a smooth or glossy stock. That smoother paper is “coated” stock, and its smoothness allows ink to sit neatly on the surface of the paper (or bunch up and smear if your density settings need to be looked at). This helps the ink display its hue and brightness better than uncoated paper. (This is why photos are usually printed on high gloss paper.)

Uncoated stock, on the other hand, absorbs ink. No matter how whitethe actual paper is, things printed on uncoated stock tend to darken as the inksinks below the surface.

So how can you ensure that the same base color printed to both stocks will still be consistent?

Compare the coated and uncoated versions of the same Pantone swatch, such as Pantone 186 C and Pantone 186 U below. You’ll notice that the uncoated swatch is a bit lighter. This is because of the darkening that occurs when printing on uncoated stock. The same Pantone spot color will look a bit different on coated and on uncoated stock.

Uncoated swatches (right) tend to be slightly lighter than coated (left) to offset the natural darkening effect that uncoated paper has. Notice that the CMYK values are all lower.

If, for example, your brand color is Pantone 342 and you’re trying to mimic the look of the Pantone 342 spot color on coated stock, use the values from the Pantone 342 C swatch. Likewise, if you want to mimic how Pantone 342 looks when uncoated stock is the final destination, use the CMYK (or RGB/HEX) value from the Pantone 342 U swatch.

 It’s worth noting, the actual Pantone ink formula for a coated swatch will be exactly the same as the ink formula for an uncoated swatch. The CMYK, RGB and all previews will be different between the two, because they’ll be designed to match the result of printing that specific spot color formula on the given paper type, but the actual spot colors are identical. They will, however, inevitably vary; you can’t expect to print one ink on two different kinds of paper and have them look identical. Therefore, if you’re looking for the same literal color to be printed on both coated and uncoated stocks identically, it may be best to try to manually match swatches, not rely on the same Pantone number for both applications.

Have a look through a Pantone swatch book and you’ll notice each individual swatch has two side-by-side samples. The left sample is printed with true Pantone ink(which, by the way, is why Pantone® books are so expensive; printing hundreds of spot colors is no cheap or simple task). The sample on the right sample, meanwhile, is appended with a “P,” indicating it’s printed with process color.

…CMYK has a limited gamut (color range) and simply cannot reproduce all colors with 100% accuracy…

You’ll see that these side-by-side samples of spot color and process color are not always an exact match, with the degree of discrepancy varying from swatch to swatch. This is mostly because CMYK has a limited gamut (color range) and simply cannot reproduce all colors with 100% accuracy, so this is not a foolproof system. Also, as mentioned earlier, spot colors print a solid layer of ink, while process printing creates color with halftone dots. Still, the values listed on these Pantone swatches are generally your best bet for at least getting as close as possible.

Due to the limitations of the CMYK gamut and halftone printing, some colors will be more consistent than others when translated from Pantone.

When choosing colors for a client, I often try to find Pantone swatches with as little discernible difference between the spot and process sample as possible, since most clients will rarely (if ever) be printing with a true Pantone spot color ink.

One rule of thumb I like to go by is if a CMYK value that has at least one ink at or near 100%, I know it will usually give you a richer and more consistent process color output than a swatch with process colors all at low or mid values.

OK, so what about RGB and HTML color?

The RGB and HTML values accompanying each Pantone swatch are the values you should use for digital media. For example, using a Pantone color in an on-screen presentation or as a color for a website.

A quick refresher on RGB vs. CMYK

RGB is the color mode of virtually every electronic display, from your phone to your computer monitor and probably your TV, and it is effectively the opposite of CMYK. In process printing, the paper starts white and brightness is subtracted with colored ink until eventually you reach black; conversely, in RGB, the background of a display is black by default, and colored light is added until eventually white is created.

HTML (also called HEX) is exactly the same as RGB. They’re the same thing; HTML/HEX just uses a different method of entering the color values. Hex, is short for hexadecimal, is a digital numbering system that includes 16 basic single-digit numbers rather than 10.

RGB/HTML/HEX has a different gamut from CMYK/4-color/process (and Pantone for that matter) and while the two mostly overlap, there is still a narrow range of specific colors that can be printed but which cannot be displayed accurately onscreen and vice versa. For example, very deep, dark colors can be an issue in RGB since by default there’s always at least a little bit of light creating and illuminating the colors your eye perceives on a backlit screen. Conversely, bright whites and neons tend to be problematic in the world of paper and ink, where adding color necessarily means darkening to a certain degree. Also, this is a good point to mention that you cannot actually print white using a standard printer, since there’s no way to mix colored inks together and create white. Anything you designate as white in your document will just be the plain paper color.

(Print and screen also have different resolutions, with print generally being much higher, but that’s another topic altogether.)

What this all means for you and me

If you want to mimic, for example, Pantone 109 C onscreen, you should input the RGB or HTML value from the Pantone 109 C swatch. What you shouldn’t do is pick a Pantone spot color swatch and then export that in a jpeg, or use the eye-dropper tool or something like that. Again, this takes precise color control out of your hands and leaves it to the assumptions of a computer algorithm. Always use the values on the Pantone swatch.

Note that just because you manually set your swatch’s CMYK value to what’s on the Pantone swatch doesn’t mean the RGB is correct, too. To the contrary; as I mentioned earlier, there’s no precise way to convert colors from one colorspace to another, so if your color is correct in one color space, it’s wrong in he other. Calibrate for your intended purpose. Remember, that to properly output RGB color, your entire document should be set to RGB color mode.

What is to be provided to clients in a style guide and logo suite.

The style guides that we provide for clients are made with consistent color reproduction in mind. No client should have to purchase a Pantone color book to print their jobs properly. This is why we go the extra mile and provide a suite which includes every permutation of their logo dialed up in each of the below color modes and in multiple file types.

  • Pantone Coated
  • Pantone uncoated
  • CMYK with values from the coated swatch
  • CMYK with values from the uncoated swatch
  • RGB (Which is taken from the coated swatch by preference)
  • White / Reversed
  • Standard Black (1 Color)
  • Rich Black (CMYK)

A note about black and white

White is easy. It’s all colors at max in RGB, and all colors at zero in CMYK. Even the computer won’t mess that up. Black, on the other hand, is a whole n'other story.

If you dial up black in RGB mode, you’ll get a slightly different black than you would if you hit the black swatch while in CMYK color mode. RGB black is 0/0/0 that’s simple. No light = black. But in CMYK, if you try to do the opposite and crank up all four process inks to 100% each, you will get a very rich black (the one called “Registration” in InDesign’s swatch panel and what people in the industry call Rich Black), but you’ll also waste a ton of ink if you max out every color in your printer to create black.

I could go further into this, and other color mixing standards that exist, but for now, just know that standard CMYK black is dialed in as 0/0/0/100, and you should generally just go with that for things like black body text copy. (This is referred to in the industry as Standard Black) You can choose make your blacks darker and richer by mixing the four process colors if you so choose, but at the expense of more inks being used on every single instance of black coloring.

In conclusion

Properly utilizing Pantone colors is your best chance at fighting color discrepancy. But this should be considered more of a loose guide to a journey with many variables than any guarantee of success. The fact is, every printer is different. You could send the same file to ten different printers and get ten slightly different results—or even use the same printer all ten times and windup with variances. All paper is different, too, and paper and ink are both sensitive; conditions like temperature, humidity, light, and even the mere weight of the paper can affect printing results. A perfect process printer in perfect conditions couldn’t replicate every single color the eye can perceive with 100% accuracy; that’s impossible. Even if it weren’t and all your print materials were perfectly matched, every screen in the world would still be different, capable of being modified to display color differently and to be brighter or dimmer than the one you’re looking at. On top of that, apps like Flux and built in blue-light filters are all the rage these days because screens are destroying our eyes. It has affected my computing life and adds another step to my designing process when doing color sensitive work.

Color isn’t a precise studio recording you can play back at will; it’s an ongoing live concert. The same notes may be played on the same instruments night after night, but the production is always unique to some varying degree. Put bluntly, there is no true perfection in color reproduction. You won’t achieve it. If color is extremely important to you, your only solution may be testing and tinkering over and over and over until you finally get acceptably close to the results you desire. The best we can do is equip ourselves with the right knowledge and tools and prepare our style guides in a way that avoids some of the avoidable pitfalls along that journey. We will do the best we can and explain the best we can when asked.

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