Printing & Design Tips: January 2001, Issue #6

4-Color Process Vs. Spot Color Printing

When combined, the four process inks--cyan, magenta, yellow, and black, or CMYK for short--can produce a wide range of colors, often far more than you will need for your project. However, if you must match a specific color, let’s say for a logo, in some cases the process “build” of that color will be muddy. It will lack clarity and crispness.

In these cases you may choose to add a fifth or sixth color. This color will be premixed from a “recipe” listed in a Pantone, Trumatch, or other spot color chart or book. With this Pantone or Trumatch book you can communicate the percentage components of your color accurately to any offset printer.

Keep in mind that the press on which your job will be printed must have an adequate number of units. For instance, a job composed of four process colors, a fifth spot color, and a varnish can be printed on a six color press or on a four-color press with a wash-up between printing the process colors and the spot colors. Regardless, adding a spot color can significantly drive up the cost of the job.

Also, when choosing both process colors and additional spot colors, make sure you note which is which in your page-composition software. Quark, for instance, provides a “spot”/“process” dialog box for this distinction. If you mistakenly define a spot color as a process color, the software will separate the color onto the four process plates when you print your job. Just to make sure, print a proof of all separations before you send your job to press. If you have a sheet of paper for each process color and also a sheet of paper for each spot color--with the proper elements on each--you’re ready to go.

One final note: Choose both spot colors and their process equivalents from a current Pantone swatch book that specifically notes both Pantone spot colors and their nearest four-color matches. These books also note the percentage of CMYK needed to create the color you have chosen. Exposure to light changes these color swatches over time, so, to be safe, replace your books yearly.

Keep in mind that this conversion can go both ways. If you have a specific color you want to match and you want to limit your color palette to the four process colors to control costs, you may find that the four-color equivalent noted in your swatch book actually does come very close to the spot color you have chosen. If this is the case, you may be able to keep your job on a four-color press, which would cost less per hour than the six-color press you would need to print an additional spot color.

Web Vs. Sheetfed Printers

Depending on the length of your press run, your print job will be produced on either a web (roll-fed) or sheetfed press. It pays to learn what equipment your printers have on the pressroom floor--and hence what kinds of jobs your printers focus on--since most printers do not have both web and sheetfed capabilities.

As a rule, web presses are best suited for longer runs. Web presses run at much higher speeds, and most have some finishing capabilities (folding, gluing, etc.) at the delivery end of the press. Whereas a press sheet comes off a sheetfed press as a large, flat sheet of paper, a web press may deliver a complete, folded signature, ready for binding. This can speed up the entire production process significantly.

Sheetfed presses are best suited for shorter runs and where showcase quality is required. Sheetfed presses can also run heavier paper, and conversely web presses can run newsprint or other thin paper. Some sheetfed presses can turn the sheet over within the press and print both sides in one pass. However, all web presses must perfect (print both sides at once), since it would be nearly impossible to run the roll of paper through the press a second time while achieving close register.

As a general rule, consider a web press when the number of impressions exceeds 25,000. Remember that a brochure that would fit “six-up” on a sheet would count as 1/6 of 25,000 impressions. If you are confused as to which press would be more appropriate, bid out your job to both web and sheetfed printers.

[Steven Waxman is a printing consultant. He teaches corporations how to save money buying printing, brokers printing services, and teaches prepress techniques. Steven has been in the printing industry for thirty-three years working as a writer, editor, print buyer, photographer, graphic designer, art director, and production manager.]