So often lately I hear the phrase “paper is the fifth color in printing”. It is certainly true that the color of the paper, even when looking at shades of white, will impact the way color will build when printing with transparent inks. It is less common to hear mention of paper formation and how it will impact the print quality and reproduction. I believe this is because paper quality, of which paper formation is a component, is just expected. When ordering paper, formation is not something that is specified, we just assume we’re going to get it….and it’s going to be good.
What is Paper Formation?
Formation is defined as the degree of uniformity with which fibers and other papermaking solids are distributed in a sheet of paper. The more uniformly these materials are distributed, the better the formation. Poorly formed paper will have light spots and a “clumpy” or “flocky” appearance.
Why is Paper Formation Important?
Very simply, a paper with uniform formation will tend to print more evenly than a paper with non-uniform formation. When printing large solids or areas of heavy coverage, this becomes very apparent. Paper with uniform formation will also tend to have uniform ink density. Paper with poor formation will have areas with clumps of fibers and areas with very few fibers – this will create mottle when printing because the ink will absorb non-uniformly.
Formation is something that all mills try to control and optimize through fiber selection, refining strategy, manufacturing SOPs and many other variables. When you order paper, generally you are specifying the brightness, thickness (caliper) and finish. Typically, mills do not “publish” formation targets, but they are certainly part of the internal mill specifications.
If you go into a pressroom, it is not unusual to see the pressman holding up the paper and looking through it towards a light to see how uniform it is. As you plan for your next job, request paper samples so you can do the same! Tape your samples to a window and look at them with the daylight shining through. Then, demand consistency! A paper with more uniform formation will print better and help your printer meet your job expectations.
Remember, not all paper is created equally. Just because a paper has the same brightness, smoothness and caliper specifications as another product doesn’t mean it has the same sheet structure. A paper with better formation can help take your job from good to great! You CAN put this much ink on uncoated paper, and well-made paper can help bring your design to life.