Color Separation . . . Whadd’ya Mean?

It happened again. One of our customers commissioned a new logo. She paid a website designer for the concept and the art. She was planning ahead. With the understanding that 2 color printing is far more economical than full color, she asked the designer to develop a two color logo that could be used on her letterhead and envelopes.

The designer followed her instructions. He produced a logo that used 2 colors, but he created the art in Adobe Photoshop, RGB color mode for screen, sized about 2″ x 3″ at 72 dpi (dots per inch). He did everything just right . . . for the Internet; and just wrong for print.

Now, if all of that printerese jargon has confused you, hang on ’cause I’m gonna ‘splain it to ya.

Here’s a logo. No liability here, it’s not a real product . . . dairymen don’t last long around lactating tigers. We’re just going to use this to illustrate how colors work for the Internet and for print.Specifically, we’re going to talk about how colors go together on your computer screen and in a printshop.

First, notice that you only see three colors in the art — orange, green and black. Strangely enough, the logo at the right is actually comprised of three colors. It’s put together in RGB color mode — Red, Green, and blue.

 

 

 

 

Here’s an illustration of how RGB works:

These are RGB color separations. The image on the right is a composite. RGB is an additive color mode. Here’s how it works. Red, green, and blue wavelengths of light can be combined in various intensities to make a wide spectrum of color. If you add all of the colors together, the result is white. All of the visible wavelengths of light are transmitted to your eye. That’s what’s happening in the illustration above. Various shades of red, green and blue combine to make the tiger. The solid colors in the background combine to make white.

Interestingly enough, combinations of two of the three colors together create the secondary colors used in printing. Red and green combine additively to make yellow. Blue and green combine to make cyan. Blue and red combine to make magenta.

The secondary colors can also be combined to make a spectrum (or color gamut). Printers call this process color. The RGB color gamut you see on your screen is a little bit larger than the gamut that can be printed on a printing press. Your screen gamut will also be dependant upon external lighting conditions and about exactly 1,763 other variables that are way beyond the scope of this little blog entry. Here’s the important part: What you see on your screen will rarely match what you see on Bob’s screen next door or Mary’s screen in the next cubicle. And Poor Richard’s law #47 states that what you see on your screen will NEVER, NEVER match what is printed on paper!

Process color looks like this:

 

You’ll notice that we’ve added another color to the three secondary colors listed above. The four process colors used in printing are Cyan, Magenta, Yellow, and Black (CMY and K for black). In an ideal world, the combination of Cyan, Magenta, and Yellow will produce black; but the reflectivity of printing inks is not perfect. CM and Y combine to make kind of a muddy, ugly brown; so printers add black to be able to produce a solid black color.

CMYK is a subtractive color process. The inks combine to actually absorb (subtract) certain wavelengths of light. The remaining wavelengths are reflected off of the paper. You see this as color. White is close to 100% reflectivity — nearly the whole spectrum is reflected. A true black would have 0% reflectivity. A large part of the entire spectrum of visual lies in between and can be produced with combinations of cyan, magenta, and yellow, with black as an enhancement color.

Now, back to our logo problem.

RGB obviously won’t work. It’s an additive model based on a mixture of light, not ink. If you mix red, green and blue ink you get blecch, a completely new color that no one wants to see in print. So our customer’s logo will have to be converted. We could convert it to CMYK color and print it on a printing press, just like the tiger above. But there are some practical and economic problems. When CMYK is printed on a printing press, four actual inks are put on the paper. This requires either a four color press or a couple of passes through a two color press.

Four color presses are more expensive to purchase, setup and operate than smaller and simpler 2 color presses. Typically, there is also more paper waste involved. At AlphaGraphics, our minimums usually start at 1000 12.5 x 19 sheets for a process color job. In this case, that means 2000 pieces of letterhead for a customer who really needs half that much. Running full color in two passes through a 2 color press is even more problematic, the biggest difficulty being that you really don’t know what the final color will be until the second pass . . . and then it’s too late to do anything about it.

Our customer’s logo was also sized for the Internet. The size was approximately 2″ x 3″ at low resolution. When we shrunk the size of the logo to increase the resolution and clarity for print, it turned out about this big:

Tiger Logo

Envelopes are also a problem. Most conventional four color presses don’t like them. We tried to run envelopes on our color press once and spent half a day removing shredded envelopes from the rollers. Not fun. So, that means that process color envelopes have to be ordered from a specialty printer. Again, more expensive, 2,500 minimum and 2 – 3 weeks lead time; it’s not a good alternative for the customer.

Here’s the solution:

spotcolorillustration.jpg

It’s a two-color tiger. In this case, all we did was change the color of the tiger’s eyes. Now, we’re going to print him in spot colors, orange and black. We’ll actually get the effect of more colors by shading the orange (with screens and gradient fills). And we’re going to get the right color. We’re going to mix the ink to specifically match the orange the customer wants.

In this case, the orange is PMS (Pantone Matching System) 158. Pantone makes neat books for printers that tell us how to mix colors. We’ll mix the orange ink and compare the solids in the printed product to a color swatch in the book. This doesn’t mean that there will be absolutely no color variations in the final product, but it should be really close to the PMS color specified. Please note: the ink color will match the Pantone book, but not necessarily your computer screen. Even if you waste a lot of time trying to calibrate your screen, the only reliable way to see a Pantone color is ink on paper.

This is what our customer originally had in mind. Two color printing is done on small presses. It’s economical to produce very short runs and most of the small presses we have will run envelopes, too. Unfortunately, her designer didn’t understand this at all.

We talked to the web designer. Nice guy. He had produced a really good looking logo and had not the faintest clue that his customer wouldn’t be able to print it. He also had no idea of how to draw a logo for print. Of course, the project was delayed for a week while everybody traded emails until all of this could be determined. In the end, our customer had to pay for additional design time for us to re-create the logo in Adobe Illustrator as vector art with specified Pantone colors.

What are the lessons to be learned from this?

  1. Poor Richard’s First Rule: Ask your printer. Ask your printer. Ask your printer.
  2. Make sure that the designer you hire understands how to design for print. Do not assume that he does. Many graphic designers are fine artists and web designers, but lack the technical knowledge needed for print on paper.
  3. Be very specific. Talk with your designer about exactly how you want to use the art they will create. Choose specific colors. Make sure that you discuss the cost implications of the art that they will design.
  4. Finally, involve your printer in the project from the outset. We think that it’s best if you have a direct relationship with your printer. If he is involved in the project from the beginning, he can work with your designer on the technical aspects. This will save you money over the long and short run.
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8 Responses to Color Separation . . . Whadd’ya Mean?

  1. Jim says:

    Richard-Keep up the good work on the site. My wife an I bought a print shop in October and we have enjoyed all of your posts. It’s nice to know we are not the only ones who have these problem.

    Thanks again!

  2. Janet Carter says:

    Hey, Richard: Just wanted to say thanks again for completely screwing up my workflow—-every time I log onto the AlphaGraphics site to upload a file, I get snagged by your blog and have to spend a half hour or so wandering through your latest posts. Can’t imagine how you find time to write them all, but I’m glad you do. Never been here that I haven’t found something amusing or informative or interesting, and all of it invariably well-written. Take it from a frustrated novelist who knows: writing well is an increasingly rare talent in the world today. Thanks for proving it’s not entirely a dead skill, and thanks for sharing it with us all.

  3. Pen says:

    Ah, yet another post I will make a copy of…

  4. Wayne says:

    Thanks – You would make a good teacher. Your writing and explanations are easily understood. I have learned a lot from reading your article on color separation!

  5. Gary D. Warner says:

    I once had a traditional offset print job done which utilized 2 color separations from a full color photo. (Note: I’m definitely NOT talking about “duotone.”) This is a distinctly different process with the finished image producing the illusion of full color (virtually). It worked best using deep blue and orange inks, the orange lending itself well to producing natural looking flesh tone, for example. (Note also that this predated the proliferation of PC digital technology)*.

    I am again attempting to locate a professional printing firm with knowledge of this process that also provides it (naturally). *I’m after hard copy, not cyber results.

    Can you help? (I’m located in mid-Michigan. The firm used was in the Grand Rapids area but I no longer know its name, address, etc.)

    Thank you,

    Gary D. Warner

    • poor richard says:

      Gary,

      I vaguely remember seeing ads for a process like this in the late 90’s, but I never knew anyone who tried it. If I recall correctly, the effect was a kind of sepia-color. Really can’t help you find a source, though . . . sorry.

  6. dfoy@sas.upenn.edu says:

    I need a four part color separation mechanical do you do that type of work?

    • poor richard says:

      Sorry for the delay with a reply. I must have missed the email when it came through. Can’t imagine why you’d need a mechanical today. There are lots of ways to print separations if this is what you’re really looking for. Alternately, you can convert to .pdf and look at the separations in the Advanced:Print Production: Output Preview menu. Hope this helps.

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