overprint versus trap, inks

I’m just about to send out for plates for a business card project and am curious about the following.

This side of the business card is 3 color. I’d like to know if I should knock the blue (PMS 2418) out of the gray background (PMS Cool Gray 1) or if it should overprint the blue. If a knockout, what trapping amount do you recommend? The paper is Crane Lettra 220#, flourescent white.

If I overprint, I would obviously have to do a kiss impression of the gray background. I may remove the background pattern altogether as it might be a bit much for my first press run. I’d like to push the limits though.

I’m very familiar with offset lithography overprinting, trapping, etc. but this is new territory. I realize that I’ll learn a lot of these answers with practice but I’m just really trying to prep the files correctly up front so that I have the correct plates to work with.

If overprinting, I’m not yet sure how opaque this vanSon rubber-based inks are.

Are there any letterpress standards like SWOP, G7 or SNAP? I think I know the answer to this but I thought I’d throw it out there. :)



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I would avoid overprinting the blue, given how much thicker letterpress inks are…But overprints always pop out at me.

I haven’t dealt with trapping in relief printing beyond a few projects (or in offset for that matter), but I’m working through a 3 color project now.

The artist is hand-cutting the blocks, which will probably be combined with hand-set type. We are aiming for approximately a 2 pt. trap. We are also planning on introducing some ink squeeze/density effect, which will be wider than the carved trap on one block. This is for artistic effect…It might not work so well on a biz card.

I suspect the easy answer would be to make sure the trapping is large enough to hide the potential registration error of your press.

SNAP makes a mention of letterpress in their 2009 guidelines. There is also an article on applying G7 to flexography (somewhat letterpress-ish) here:


Tell us what you do! And good luck.

I’m not sure you’ll see the gray under the blue. If you mention artistic effect, over printing can look very artistic since the two colors will make a third where they overlap.

If you decide to have 2 pt stroke trap and there is color change where they overlap then ask yourself if that is okay rather than overprinting both colors and trap.

I enjoy seeing colors overprint which it gives a nice artistic affect.


use opaque blue

One other factor to consider is that the “sheen” of the ink may be different where it overprints another color. It will not have the same absorbancy as it does when it is applied directly to the raw paper surface.

Thanks, everyone. Great points. I decided to have two plates made, one overprinting and one knocking out with trap. I’ll be sure to let you know the results.


We run alot of this kind of work and very, very rarely knock anything out. If there is a decent amount of contrast between the colors, they should overprint fine. Your grey is so light that i think you will be good.
When we do knock stuff out we don’t trap either. Maybe some shops have good results trapping, but my experience is that the trap becomes visible in a lot of cases, and looks more awkward than just overprinting. Our heidelbergs register well enough that i don’t need a trap for registation issues.
Good call on getting two plates.Try out both plates and see what you like.
I am with Casey on the beauty of on overlap. I think a lot of letterpress these days looks too computer aided, or to much set up like what people are used to seeing on screen or from offset, but just with “impression”. It can start to look kind of stale. I like it when people can get loose and let the medium and the layers get physical again. Experiment! :)

Have a think about laying down your blue and black first using opaque inks, then overprint your background with a transparent ink.

You would want to lay the background first with transparent ink and then use an opaque mix with the blue (the black will cover anything). The background needs to be very light, but the opaque quality of the ink should cover it.