Answered by Tom Loudon, VP Printing Operations, EU Services

Question:
I recently printed a catalog insert on a 50# offset stock using two PMS colors, one of which was PMS 285. The PMS 285 looked washed out and mottled. In order to get the ink dark enough, the printer had to run the ink very heavily, producing dots that did not run cleanly (mottled blobs). When the ink density was backed off, the ensuing color was way too light. The other PMS color we chose printed very nicely.

The printer’s explanation was that the recipe for PMS 285 blue ink consists of 50% transparent white. Is it true that the transparent white would cause a problem like this or is there possibly another reason? Do many inks contain transparent white? If so, how can we make better color choices in the future so this does not happen again? We have three different PMS guides, but none of them list the make-up of the PMS colors.

A.M.

Answer:
PMS 285 does contain a high level of transparent white and is a difficult color to run on press . Its composition and the transparent white can tend to accent the grain in some offset papers. If the ink on the print run was mottled, however, that indicates an ink and water balance problem rather than an ink composition problem.

For the most part, a printer should be able to come close to matching a color using a PMS (or other appropriate) ink guide and still be able to keep the dot screens open. In this case, the issue could be related to the skill of balancing the emulsification of ink and water. Or there may have been issues with the paper itself. Finally, PMS books do list the ingredients for each color just below the swatch of that color. You may want to consider getting new PMS books (which is wise to do every few years anyway).
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