Image Stretching Issue

I’m trying to get familiar with the use of my Vandercook 3, and doing a lot of troubleshooting and question asking. I’ve made a couple of reduction prints on it so far (using lino blocks mounted to MDF and adjusted to type high with paper sheets as I look for a galley height bed plate) and the consistent issue that I have is a sort of stretching of the image as it prints. I get perfect registration perpendicular to cylinder, but the image seems to stretch and distort slightly as the cylinder rolls, so the near end of the image (right side of paper after removed)  is perfectly registered and it gets progressively further out towards the other side (the left side of finished image). A colleague has suggested that this might have to do with the rubber sheet that is mounted under the tympan, which i intend to remove and replace with extra paper and continue to experiment, but I thought I’d throw it into the mix here and see if it’s instantly familiar as a problem to anyone.

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Jonathan Jarvis
Jonathan Jarvis
5 years ago

Have you considered paper stretch …is grain consistent and printing correctly according to grain….is each of first colour exactly in same place….has paper actuallystretched or image shifted…does cylinder fully engage with racking on impression that there is no play

Paul Moxon, Moderator
Admin
5 years ago

Standardize the heigh- to-paper of your form with a bedplate or galley (0.050″). All that paper makes your form springy, though your may need some underlay. Your lockup may be over-tightened causing the tail end of your block to be higher that the gripper end.
As to packing, the cylinder undercut on most No. 3 is 0.070″. I generally start with three sheets of SuPak (0.016 ” each totalling 0.048′) and then three or four sheets of tympan paper (0.006″ each) as needed for a hard, uniform caliper.

Lee Asbeck
5 years ago

If you are bringing a form up to type high you need to put the paper between the bed of the press and the linocut. The packing on the cylinder plus your paper should only add up to the undercut plus the amount of impression you want. If you have to much packing on the cylinder the surface of the cylinder is moving faster than the bed and will stretch your paper.

Widmark
5 years ago

I don’t know why this would be an issue now and not before, my thoughts might not be relevant! Running it thorugh w/ no ink would still leave an impression that might look weird. The amount of impression and the amount of image area might be causing more stretching than the art you’ve printed before?

Widmark
5 years ago

Hey Roger- Dan Selzer here!

My understanding is that it’s simply the paper stretching from the first run. Mark at Haven Press had a great solution that unfortunately won’t help you, where he actually adjusted for that by stretching the second image digitally before making a plate. Likewise with plates or type people have been known to make adjustments, but that doesn’t help with a full image or a single large plate.

Perhaps you can experiment with different paper stock? I also always wondered if it was possible to print something first, say outside of the image area, that would cause the paper to stretch?

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