Packing type

I purchased 314lb cotton paper as I want a very deep impression. However, after printing, I noticed “crinkles” in the areas in between the print. I’m wondering if I need packing that is a little harder than I’m using as I use multiple sheets of card stock. I tried taking out some sheets and didnt get as deep of an impression that I am looking for. Any suggestions?

image: crinkle.jpg

crinkle.jpg

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The paper achieves its strength primarily through the densely interwoven cotton fibers from which it is made. This strength may have been enhanced by certain additives inside the paper.

When you printed it by pressing the paper down to that extent, since the height of the paper in the image areas is now so different than the height of the paper in the non-image areas, your impression forces have exceeded the paper’s internal strength, and so it fractured. The reason it did not fracture closer to the image areas is because of the length of the cotton fibers from which the paper is made.

Getting back to the printing process, if the paper deforms the packing when the impression is made, as well as itself, thereby causing the paper to deform even more, this would of course worsen the situation. So, I would try using harder packing such as pressboard.

The only other thing I can think of is to dampen the paper before printing. This should make it more flexible. I have never done this, but I think you can put the paper in a closed container for a few hours, or overnight, with a source of dampness like damp cloths. However, be sure that the paper does not touch the damp cloths (or the source of the dampness). We have talked about dampening paper before on this site, so do a search to get better information than this on dampening. And as always, when trying something new, do a test first, so you don’t potentially ruin the whole job.

One thing I WILL say about dampening is, that it causes the paper to get slightly larger, especially in the cross-grain direction. This could cause misregister if you are printing more than one color. Also, if you put a stack of paper in a damp chamber, the edges will pick up moisture and expand more than the rest of the sheets at first, so the edges could get wavy. However, I think this will go away when the moisture content in the entire sheet reaches equillibrium. Like I said, do a test.

I dampen stock all the time, my method isn’t as fancy or controlled as using a damp chamber, though the method I use was also suggested by a member here and works great for single-color jobs.

I simply run some water onto both sides of every third sheet in a stack, and put them in a plastic bag over night. I’ve used this technique on a variety of papers and it makes a big difference.

And hard packing is almost always the right choice.

-Kim

Thank you both.

The concept for deep impression letterpress is to compress the paper fibers and not punch through the paper—that is what is causing the paper to tear in this example. When there is a Braille-like appearance to the back of the sheet, then that’s an indication of too soft a packing. Some show through impression may be unavoidable, but best examples are where this is to a minimum. Foil stampers are well versed in this technique and they often use a very hard impression surface on their platens using impression surfaces like phenolic board and cement board, and no tympan or paper packing. Multiple sheets of paper creates a cushion effect and that is soft packing even if the sheets appear to be “hard.” On hand fed platens, a cover sheet of paper tympan is necessary to place the gauge pins. And if light-weight presses like Pearls and any of the table top presses are used for deep impression, don’t expect easy, clean results and take the risk damage to the press.

And these postings to Briar are much more meaningful if the technical information is also given—size and make of press is given, type of plate, and generally, the more information the better.

Thanks Fritz1. I have a 14x22 C & P