Digital to photopolymer query

Is it possible to go directly from a digital phototypesetting program, such as Scribus, to photopolymer plates, or must a negative first be created and then burned to plates? Thank you, Rick.

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I’m not sure of the exact workings of CTP systems for offset plates, but I’m almost certain there is no chemistry involved—it essentially prints the resist on the plate and you can put it right on the press.

Ergo, for a computer-to-letterpress plate you would need a printer that could print the relief, which seems to me like something that wouldn’t exist. It would no longer be photopolymer, as it wouldn’t be a photographic process.

If there was a printer that could expose PP direct, it would need to accommodate 0.03” plates (which seems unlikely) as well as have a UV head that selectively exposes the plate (which seems even more unlikely) and you would still need to wash out by hand or have a machine that could do that.

Seems you’re stuck with negs.


What I read (either here or on the PPLP list) is that the direct-to-plate systems for photopolymer relief plates use a plate material with a mask layer that is removed selectively by laser. Then I suppose normal exposure and processing. Prof. Lange?

Now I’m confused. Which is it, negatives or laser? If the latter, I’d suspect that a direct digital interface was possible … and preferable to the former. Clarification, anyone? Thanks, Rick

Is it possible? Yeah probably. But are you willing to spend $$$$$$$$$$ to buy a CTP system? Probably not, unless you landed a packaging deal for all General Mills products and do flexo on the side.

You print a negative, and expose from there. Maybe you could “print” a relief structure with a 3D printer, but for all intensive purposes, plates are usually exposed from a film negative or otherwise printed negative.

Of course, you can always upload your digital files to a platemaking service and receive finished plates. But they will be printing a negative ;-)

As I said, the photopolymer material for CTP has a mask layer on top. It takes the place of the negative. The laser removes the portions of the mask for the image area. Then regular exposure is done. The laser does not expose the plate, it removes the mask.
If you are thinking of this as a cheaper alternative to film, think again.


Yeah, that’s how it works. I have a client who uses this, for flexo. It’s just a quick burn off and then processing as normal.

Nothing currently available for letterpress, re sizes, hardness, etc., though. I kind of doubt there will be or it would have happened by now.



I wasn’t paying attention. Minor correction. The laser “etches” the plate, or whatever, initially. No laser is required to process the plate, just a burn off (short exposure) with the platemaker. Then all proceeds as normal.