Uneven inking on a magnesium plate

I’m a invitation designer working with a letterpress printer and am trying to help him troubleshoot a problem. When he prints my invitations with large areas of color there always seems to be some areas that are dark and some areas that are quite a bit lighter where the paper shows through. I use Crane’s lettra paper which works great most of the time. I also prefer a deep impression. I would greatly appreciate any insight that anyone may have.

Thank you!

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That could be any number of things. One of the first things people are going to want to know is what type of press is he using? Platen (table top, floor model, windmill?) or cylinder (Vandercook or the like)?

Also… If you are able to upload an image then there is a pretty good chance that someone here will be able to diagnose the problem.

Can you actually see that the mag plate is not taking ink evenly? If other mag plates are inking fine and if I had to take a shot in the dark I would say that the plate is mounted on an uneven substrate like… maybe some micrometric warping in the wood is causing the plate to be just shy of type-high. But again… that’s just a guess.

I had the same issue and found out after trying about everything that the problem was the magnesium plate was not type high everywhere. If you have a caliper check to make sure the area that is printing light is type high

A good start might be reading Elementary Platen Presswork by Ralph W. Polk. Chapter IX “Simple Platen Press Makeready” explains and shows underlaying a low section on a plate, also interlays, overlays, and equalizing the impression. Letterpress is nothing like offset printing where a plate puts an impression on a rubber blanket. There are many variables in letterpress: worn plates mounted on warped wood blocks, worn type, machine set slugs that are lower on one end, platens that are unlevel, soft or hard packing, etc., etc. All these must be compensated for by a skilled, experienced craftsman. There are many excellent text books about letterpress makeready, one for starters may be Kelsey’s “Printer’s Guide.” Good Luck!

I think you need to find a printer who is a bit more familiar with the equipment and materials being used.


I agree with dicharry, some details on the press may be important here…

If your plate is consistent/type-high & makeready is good I’ve got another thought to throw out there -

Since you mentioned printing large areas of color, you might be dealing with starvation ghost - where think is stripped from your roller by a large solid & not totally replenished before the next impression. Again whether that might be the case & how to deal with it would depend on the press.

Thank you for your posts. I will see if any of this helps my printer. Does anyone know of any Michigan based letterpress printers?