In Tandem Design, Inc. Color Matching Paper

In Tandem Design, Inc. Design Project Example

Color Matching in the Printing Industry

The Photo Shoot

At a photo shoot, you are perceiving reflected color in the full color spectrum. This reflected light is captured on film. Different films have different color characteristics.

For your printed piece you choose the photo that looks the best. You do not choose the one that most closely matches the actual photo shoot. The photos do not match the product at the photo shoot, and you no longer have the photo shoot set up in front of you to compare.

You may be choosing between transparencies laid out on a light table. You are perceiving the result of a projected "white" light being selectively absorbed by the transparency. How "white" are the lights in your light table? Different bulbs are slightly different colors. You are making a decision based on relative color, not absolute color.

The Scan

The precision with which the scanner can differentiate between shades of color is determined by the hardware and the format in which the digital information is saved.

Soft Proof graphic At some point, you and the scanner operator are looking at the scanned image on a computer screen. The monitor employs selective projection (red, green and blue (RGB) phosphors on the screen glow brightly or dimly). Monitors tend to be too bright and too blue. There are ways to calibrate a monitor to more accurately represent a printed piece. Your scanner workstation must have been so calibrated in order to present a valid soft proof (the image on the computer screen is referred to as a "soft proof").

Then the digital image is translated to cyan, magenta, yellow and black (CMYK) components. The conventional process color ink-on-paper color gamut is limited. You cannot reproduce every color that your eye can distinguish using CMYK inks on paper.

The Proof

A proof is ink or dye on paper or on layers of plastic over paper. Light strikes the proof, is selectively absorbed by the inks, is reflected by the white paper under the inks, goes back through the inks and is selectively absorbed again. You perceive reflected light. The image is made with CMYK colorants. These are the primary subtractive reflected colors. RGB are the primary additive transmitted colors of scanners and computer monitors. The colorants of the transparency are different entirely. The digital proof cannot look like the image on the monitor, nor the transparency lying on a light table, nor the reflected light of the original photo shoot. You are now dealing with a severely compressed tonal range and colors that have been interpreted by the color film, by the scanner hardware, by the scanner software, by the scanner operator, by the digital proofer, and by the paper on which the proof is made.

Printing

A printer will be able to very closely match a contract proof on press. It will not be an exact match, but it can be very close, especially when dealing with highly reflective, white, cast-coated stocks, printing one image on one page at a time. But normally 4 or eight pages are printed together on a large sheet, each with different images, different ink densities, and requiring different trade-offs for color.

Always remember: proofs do not represent what you will get on press; they represent what you can get on press. You can also get results on press that do not look at all like the film proof, nor the digital proof, nor the computer screen, nor the transparency. There is a great deal that can be adjusted on a printing press to alter the color of a printed piece. There are many conditions associated with layout that can influence color on press. And there are conditions on press that vary during the press run. The first sheet, the middle sheet and the last sheet won't match each other, let alone the film proof. Sorry, it's true.

This does not mean that you cannot get a good-looking finished product. It only means that, when it comes to photographs, scans, computer monitors, digital proofs, film proofs, and printed sheets, use the word "match" with extreme caution.

What is the Objective

"Matching" color is a goal rarely reached. But is the objective to "match" color? Match what? ... the original photo shoot? ... the computer screen? ... the digital proof? ... the film proof? ... your idea of what it should be?

The objective might more accurately be stated as:

To get a printed piece that looks great as a result of all your efforts and expenditures.

There are procedures you and your vendors can follow to get as close to that objective as possible. Be aware of what your pre-press and printing vendors can and should do. Be aware of what they cannot do. And ask beforehand if you are not sure.

Thanks for visiting!

Forward comments or questions to harry@email.intandem.com

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