What size prints are you making on your 8x12?

Hello! I know this subject has been addressed many times on here but despite searching the discussion forums I can’t find the exact info I’m after, so was hoping someone could kindly help with some advice? (or point me in the direction of where I could find more comprehensive info)

I have a 9x13 platen press with a 7.5 x 11.5 Boxcar base. I know that I can expect to get a decent print from about half the chase size, and that a lot of it depends on what sort of coverage you are asking (i.e. a light vs heavy design).

But what I am wondering, from folks who print on a say a C&P 8x12 (which is guess is the closest comparable size to my press) is what card sizes are you able to successfully print?

The sizes I am concerned about printing are 5x7”, 6.7” square and approx 4” x 9”, and I guess I would just like to hear from anyone who prints on an 8x12 as to what card sizes their press is able to handle. And is that a light/minimalist design, or something reasonably heavy requiring heavier ink coverage/pressure?

I should probably just get some plates made up in the sizes I want to print and give it a test run, however that could be a costly mistake! So thought I might ask here first.

Any help would be greatly appreciated… thank you :)

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Well, printing isn’t “black and white,” it’s all in shades of gray. So there’s not a point at which a cut becomes a “solid” or a heavy forme, versus a lighter form. A large enough text plate will resist impression just like a smaller full reverse or solid, especially if we’re talking about deep impression.

The half the chase size rule isn’t really a hard and fast one in my opinion. I can run a 2-up full reverse business card on my press and struggle with an area 1/4 or even 1/6 the size of my chase. You’ll find that another unfortunate variable is how much an operator is willing to push the press into extremes and risk wearing down things faster as well.

I do not currently run an 8x12, I run a 12x18 Kluge. My boxcar base is 9x12. And my preferred sheet size? I sometimes run 8x10, but my real standard for most jobs is to run 5x7 cards. Anything larger has typically negated the advantage of running a ganged up design.

Oh, and my ultimate advice would be to start with small plates and work up to larger ones over time to see if they’re right for you. “More plate, more problems.”

If you think of the inked surface in square inches you are limited on any platen press to a specific number of square inches at different depths of impression — it takes more force to penetrate the paper further and so with the same press you can’t print as many square inches deep into the paper as you can if you kiss the surface. The size sheet you can print is limited by the size of your platen and how close to the edges you can put gauge pins. The size you can print on that sheet is limited by the number of square inches of actual inked printing surface (not the size of the plate unless it’s a solid) and the depth of impression. I can print a 9x12 sheet on my 6x9 Sigwalt, but I have difficulty printing a 3x4 solid decently on any size paper. The texture of the paper is also a factor — textured paper requires moderately deep impression just to get full coverage.

It’s a complex problem and there are no simple answers!


I’m an 8x12 C&P New Style owner. I regularly print A7 (5x7) cards on the press. I’ve also printed 8.5x11 letterhead in the past few weeks. To your question about coverage, with 3 rollers, I get good coverage on solids. About the biggest solid I’m comfortable printing on that press is 6x8 and that is the very upper limit.

A lot depends on the paper, makeready, the ink, etc… I wouldn’t try to get rich coverage of lettra at that size. I have done it, but it wasn’t easy. Also, depth of impression matters. a Solid of say 6x8 (which is 50% of the chase capacity) printed on very smooth paper, with excellent makeready and a fairly wet (non-tacky) ink is possible, but punch with a polymer plate form is out of the question at that point.

The New Style is stronger than the Old Style press. I’d go to 50% of chase on the New Style but only 35-40% of chase on an Old Style. The problem with Lettra for example is bottoming the ink (which is to say, eliminating any mottling or “saltiness”) in that relatively textured and porous paper. You can compensate for lack of pressure by using smoother paper, more ink, or dampening rougher stock like Lettra. More ink only works to a point, after which you end up with squeeze and indefinite outlines.

Basically I consider a few items:

New Style press means I can potentially cover 50% of chase square inches (48 out of 96 square inches possible). If you are running a later manufacture press like a C&P Craftsman or Kluge, or a Colts Armory, you can maybe go to 60% of chase capacity because those presses were very heavily built. Older style presses 35-40% of chase capacity in square inches.

Type of paper, and desired impression depth. more depth, rougher paper, means decreased square inches.

Type of ink, higher tack inks will pick or fail to cover when printing large solids. lower tack with more ink compensates a little when printing rough stock, but but then you run into squeezy edges if you use too much.

Running all three rollers allows for better ink coverage without ghosting artifacts showing up in the middle of your solids.

As Bob notes, its a complex problem, but those are the significant factors.

To the specific sizes you mention, in square inches all fall below 50% of chase on a 8x12 and would also fall below 50% on your 9x13. Assuming you have a newer style press you’ll be fine. The question is how much depth you want.

The other thing to remember is that you can have a form that is 80% of your chase if it has a lot of white space in it. The 50% refers to actual surface inked or contacting the paper, not the total form size. Hope that is clear.


Lots of good stuff here.
Note particularly the advice of Vrooom to start with a smaller form and work up to see what you and your press/ink/paper will do.
If you were doing four colors and each form was 25% of the chase size, you could in theory do 100% coverage. You may do essentially the same thing with a single color. You wouldn’t want 100%, but you could certainly do more than 50% with two or more passes. Real easy to do with poly plates that you cut apart.
It will of course be a test of your feeding skill as each piece must register to the others. Don’t forget that each of the first pass pieces must register to one another.