Does the amount of packing effect ink coverage?

I have a 8x12 C&P old style. The press has not been altered since I acquired it. I print with a boxcar deep relief base. To get a decent impression, the press requires a lot of packing and make ready. I have researched how to adjust the platten and I’m trying to work out if it’s necessary because the prints are a good quality but ever so slightly off when I print large forms (which is expected when the sweet spot is exceeded).

With all that said, my question is: With the amount of packing needed (much more than recommended) effect how well the press prints large dark solids. I know dark solids are not going to be completely solid regardless of what I do (just the nature of letterpress) but I’ve tried every other method to get a dark solid coverage with little success. I’m wondering if the fact that the form is hitting a thick stack of packing, rather than a hard surface + a few pieces of packing, may be part of the problem.

Any thoughts on the matter would be appreciated.

Taylor Guess

Log in to reply   11 replies so far

The 8x12 isn’t exactly the best press for deep impression, except maybe the smallest of forms. If the press requires lots of packing and makeready for even small forms, then the platen is definitely in need of adjustment. It’s not a difficult process; but it is fairly painstaking. There are descriptions on how to do this here on Briar Press and in the archives of Letpress, I believe.

Even adjusted and leveled, it will be hard to print any solids larger than 1/4 the area of the chase, even without the deep impression. If you need that, find a cylinder press of some sort. Packing hardness (or softness) won’t make much difference as you approach this size. Generally hard packing is preferred.

is your forme type high

Thanks Arie K. I’ve researched how to adjust the platten and feel pretty confident that I can do it, but If it’s not going to make a significant difference in coverage, i’m going to hold off because the prints I’m getting now are acceptable, I just avoid dark solids and when I have to print them, I use opaque white to get more opacity…. thanks for the response…. by the way, I have a cylinder press, I’m just trying to get as much quality out of the C&P before resorting to the much slower Reprex. Thanks

RRODDI… the base + form is exactly type high. I check it with a roller gauge every other run to make sure it will ink the form correctly. I’ve tried every kind of fine tuning that I can find on briarpress and still have trouble with large dark solids. the reason i’m so concerned is because the solids don’t have to be that large. If the ink is black/really dark, the print will be salted (more so that i’ve seen other printers produce with the same setup)

One thing I haven’t tried is putting on a third roller. Will this make any difference? I’ve been told it may help…

Yes, three rollers will give you better inking on solids. But starting with a very firm packing is essential. Use very dense material for the packing. That will give you more even impression and also help get full impression strength in the center areas of solids.

John Henry
Cedar Creek Press

Test complete…. The amount of packing was drastically effecting the coverage of dark inks. The image I’ve attached is the new print coverage after the adjustments.

I have not adjusted the platten yet. Here’s what i did to test weather or not it would effect the coverage. I bought two pieces of stainless steel each about the thickness of a piece of cover stock, and put it on the platten with a couple sheets of packing… This increased density is a game changer for my shop. The coverage is 100% solid but requires a double ink pass to get this amount of coverage, but still, this is way better than I WAS getting with hitting the paper 4/5 times… So this is evidence that it would benefit me to move the platten forward a slight bit so the press requires less packing…

Thanks so much for your help, I really appreciate the input.

Happy printing!
Taylor Guess
Crink Press Letterpress

image: IMG_1464.JPG


Hard packing makes a big difference. I used sheets of laminated 100# text. They measures about .017.

I also print on an 8x12. Another factor to keep in mind is dampening. Solids will be much denser and no specks.

Yes. I’ve tried the dampening the paper, it works pretty well. The digital print shop that our letterpress shop is attached to has a mister that keeps the humidity lever at a certain lever, I place the folio sheets under that mister for an hour or so before cutting down to print sheet size, and it moistens the paper just right.

But this recent adjustment has made the biggest difference.

You will want to keep a certain amount of packing though, as it gives you greater lattitude in the weight of stocks you can print and the amount of impression you will need. There is a tremendous difference in packing/makeready between the form shown above and then going to a single line of 6 point type on the same stock.

If you find yourself alternating between coaster stock and onionskin, you’ll find that having room for .050 in packing (nearly a 1/16th of an inch) will cover most of the projects you will encounter. Having hard packing (the stainless steel sheets you mention) is great, but must be used with greater care lest the press be overpacked with nowhere for the extra impression to go—save breaking the press.

Nice looking job BTW.

Michael Seitz
Missoula MT

Yes, this does look good!

I’m just curious — what ink and what paper are you using?


FWIW, I leave room for about .065” packing on my 10x15. However, I use a .004 clear mylar sticker stuck to my manilla tympan “topsheet” which is .006”, so the two of these things are taking up .010” of that .065 space I have my platen depth set to. Yielding space for .055 to allow for stock and extra packing and tissue in the right spots.

We print a lot of 4 pt museum board and 500 GSM somerset here so frankly, we can use the extra room for packing, but it’s not a big deal for me to put a .030” piece of steel in there if need be or just fill it with red pressboard if I have something thin to print.

This is printed with Vanson rubber base Pantone Black on 110# Crane’s Lettra Pearl white. I know i can get an even better cover with a little bit of opaque white mixed in, but I was just testing to see how well it could cover with just black, and i would call it a success :) I ran a few jobs since this test, and it’s game changing. Type and large areas print better because of the harder surface. The impression in the paper even looks better it has less of a beveled look and more crisp on the edges.

mike, I understand what you mean. I have the stainless under the packing. when I print on 220# stock i still have to use about 2 sheets of cover weight to get the right impression. so it’s not like the metal is the only thing packing the press. I was thinking i had too much metal and first, and was worried about crushing my plates, but i measure the thickness with a micrometer and made sure that it’s not going to be too much. so, i have it setup so that I can leave the metal sheets in there and only adjust paper packing when going back and forth between double thick stock and text weight.

I’m really thrilled to see how much of a difference the denser material made in the consistency of impression, and ink coverage.

Thanks for all of your input. This is my first time to post on here with inquiries about my press, and it’s such an awesome resource to have at my disposal : ) please keep the tips coming. I still consider myself a novice printer, I’ve been printing for only 2 years. I still feel like I have SOOOO much to learn. on that note, I’m on the verge of getting my partner to get a windmill soon, so I’ll be asking a lot of questions because I have very minimal experience running Heidelbergs.

The image below shows the crispness of the edges that this new setup achieves… This was printed with a cool gray mixed from rubber based ink printed on 110# crane’s lettra pearl white. I’m very pleased.

image: IMG_1473.JPG