Direct to plate polymer photogravure - any step by step guides?

RogerHyam

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I came across a cheap copy of "Polymer Photogravure" by Clay Harmon (Focal Press 2019) in a charity shop and it has got me thinking about having a go. Other than the press and the consumables I have all the bits and pieces to hand.

Clay Harmon's book is based on making an inkjet acetate positive and using an aquatint screen to make the plate but I've noticed that since the book was published most people (including Clay) seem to be using a direct to plate method, that is inkjet printing onto the polymer plate rather than making a separate positive. I have an Epson R3000 that should be capable of doing this.

When I look for the approach to take to create and print the positive file I'm coming up against a wall. There are plenty of videos on YouTube of people doing this process and a few blog posts but they all jump over the most tricky bit of creating the positive. I need to know how to include the aquatint element in the image. I'm presuming this is because many of the people who do this technique earn a living from workshops. But I'm not a workshop type person and even if I was to do a workshop I'd want to work through the whole process before I took it. I see workshops as for the intangible/ineffable part of the process not the mechanics.

I may be totally missing something but can anyone point me in the direction of a guide to producing digital positives to be printed direct to photopolymer plates? I'm looking for the principles involved as much as the "slide this slider in photoshop" type instruction.

(Of course this is creating a digital positive so may not belong in this forum! I can't put it in the alternate techniques because it contains digital. Maybe it is homeless...)
 

koraks

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I'm glad to hear you're still alive and exploring!

I've done only a brief foray into photopolymer intaglio printing and I didn't do DTP (direct-to-plate), but perhaps I can be of help nonetheless. One 'trick' of using inkjet for the halftone pattern instead of a separate screen is to simply use a single channel on the print head - typically black, which generally has good UV coverage. This way, you use the inkjet's halftone patterning as your 'aquatint'. I did it this way with inkjet positives and it should work just the same for DTP.

The Epson print driver has an option to use 'black only', or you could use QuadTone Rip to accomplish the same (and with somewhat more control over what happens).

There may be alternatives, but when I meddled in this process, this is how I did it and the principle worked.
 
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RogerHyam

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Thanks. That makes sense and would be quite simple.
 

Taylor K Nankervis

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A fascinating branch of printing.
At one time there was a large community of photogravure practitioners workshopping here in Australia. I am probably going back 20 or so years, remembering their many beautiful works produced in Hobart, Tasmania and exhibited in bespoke Salamanca Place galleries. Fragments of memory seem to recall a few of those works being in colour, but that would be quite the challenge for PG when darkroom printing in colour was still very much in vogue at that time. .
 

koraks

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RogerHyam said:
Thanks. That makes sense and would be quite simple.
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Yeah, just give it a try. One thing you may want to look into as well is the collimation of your light source. I ran into this issue when I was doing this process, but I wasn't in a position back then to solve it. It would have been different today with high-power COB UV Leds easily available. A key issue you may run into with photopolymer is that of dot gain, which essentially means that light bleeds around the inkjet dots, creating cone-shaped light bundles within the photopolymer substrate. This results in problems like false biting when developing the plate, but also gross non-linearities in the transfer curve, requiring a very strong adjustment curve. To make matters worse, the effect can be variable across the plate esp. if you print using a film-based positive, as the contact between the plate and the film varies. This should be no problem of course if you do DTP.

The problem can be avoided/reduced by using a collimated light source. The sun is a good one, but point sources like old-fashioned plate burners will also work. Modern COB LED sources will work if you put the printing frame at some distance to the light source. I expect that if you use a more diffuse or multi-point light source, i.e. UV tubes or strips of UV LEDs, you will run into this problem. However, having said that, I think that several contemporary photopolymer printers are using UV LED strips for their light sources, so apparently the effect can be sufficiently consistent to still allow good linearization. Personally I'd still strive for a collimated/point-source light source to avoid the problem as much as possible.

Btw, there are some active photopolymer people on the forum; I think e.g. @KYsailor and @Graham06 fall into this category. Perhaps they can share their experiences here.
 

Lachlan Young

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RogerHyam said:
They don't seem to offer photogravure courses at the moment though.
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If it's EP, there's a Photopolymer Gravure course using Toyobo plates in February.

Taylor Nankervis said:
Fragments of memory seem to recall a few of those works being in colour
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Like a lot of assembly printmaking processes, people want to make it seem really difficult. Registering the plates and keeping a plate mark that looks like our culturally conditioned understanding of what a plate mark should look like (if you want it) is the tricky bit, depending on the plate substrate etc

koraks said:
A key issue you may run into with photopolymer is that of dot gain
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There's the whole question of dot hardness from inkjet, but it nevertheless works acceptably for many (with the further caveat that photopolymer gravure is often intentionally misusing the materials relative to their design aim in the first place). That said, at anything over very small sizes, point source (or at least adequately point source in effect) and a vacuum exposure unit are really quite essential. Compared to most other uses of inkjet neg/pos output for further UV processes, the one demanded by Toyobo plates (and the like) for gravure is not difficult to achieve.

The necessary con-tone positive is also easily generated in the darkroom, Photopolymer Gravure pre-dates the use of inkjet negs by several years (the necessary documentation is not hard to find, it just depends on your willingness to spend on sheets of Ortho+ etc). If you really have nothing better to do, you can also generate your own analogue stochastic half-tone screen on litho film.
 
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RogerHyam

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Lachlan Young said:
If it's EP, there's a Photopolymer Gravure course using Toyobo plates in February.
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Ah ha I missed that because it was called "Toyobo Weekend". I've just booked onto a "Photo Plate Lithography Weekend" at the start of November to at least experience printing and the studio. I'd think of switching but I will probably be traveling for work in February. Maybe in May 2026...
 

Graham06

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koraks said:
active photopolymer people on the forum; I think e.g. @KYsailor and @Graham06 fall into this category. Perhaps they can share their experiences here
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I am still too much of a beginner to give good clear steps ( just one print so far I like) but I do want to say it absolutely can be done affordable at home:
100+ watt uv lamps are cheap on Amazon $50ish
A roll of pcb photopolymer costs $12
I used the photopolymer to mask and etch copper but I found you don’t need to etch anything: the thickness of the film is sufficient for etching
Lastly, I have a nice small press (maybe $400? I forget) from a south African seller but I think you don’t need one: get yourself a ball bearing barren used for block printing . I have one too but can’t be certain I have tried this combo. (Will post here if I do)

All in all it is very affordable and the look is beautiful and can’t be reproduced any other way
 

koraks

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Graham06 said:
A roll of pcb photopolymer costs $12
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Thanks for chiming in! The film was what I used back then as well since plates were not a common item on the consumer market (things have changed since then). I also found that the film was thick enough to hold sufficient ink for a convincingly deep black. Laminating the film is/was a bit of a trick, but easy to get the hang of. The one thing I never managed was to get clean edges; the film would always crumble a tiny bit along the edges and that would create a dark edge around the print.
Btw, I now use a paste that's chemically similar to the film for etching PCB's for electronics. So I still do a little 'photopolymer', I guess. Just no intaglio printing!

Lachlan Young said:
There's the whole question of dot hardness from inkjet, but it nevertheless works acceptably for many
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Yeah, I never found dot hardness/edges to be a problem. The real issue is really what I said - dot gain due to lack of collimation and/or poor film/plate contact. I can attest to what you said; a quasi-diffuse light source worked OK-ish for small prints (up to 5x7" or so), but larger ones exhibited problems with darker patches.

Lachlan Young said:
If you really have nothing better to do, you can also generate your own analogue stochastic half-tone screen on litho film.
Click to expand...
I tried that with x-ray film. Never got a result that worked. Didn't stick with it too long, though.
 

KYsailor

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Mr Hyam,

Here is quick summary of my experience. I learned the Direct to Plate (DTP) method from Clay Harmon in Asheville NC at a workshop he offers several times a year. Despite the fact he wrote the book you reference, the state of the art has moved on quite a bit since the time he wrote it. Although, as Koraks has pointed out there may be some technical issues with this approach, I have been able to produce beautiful prints at the scale of 8X10 inches. In the DTP method - the positive is printed directly on a photopolymer coated steel plate using a high end Epson printer that can print on thick, flat loaded media. exposed to 365nm UV and then "developed" in water to produce "relief" and subsequently re-exposed to UV to fully harden the plate. No aquatint or intermediate "positive" is used.

Clay has a extensive blog he maintains and contains some instructions for getting started. (https://clayharmonblog.com/posts/dtp-quick-start). Please note that his instructions have been updated as he and others have developed the DTP technique. Nevertheless it contains a wealth of information. As I noted the DTP approach is based on the the use of Epson printers and software called Quadtone RIP and QuadToneProfiler-DN, I should add, both are Mac oriented ( I was able to make some prints using a windows based computer - but it was painful and I just ended up buying a mac)

Clay runs workshops at his studio each year, however they are in Asheville NC which may not be practical for you. If you look at his studio business which supports people who are interested in polymer photogravure - it is called Mountain Intaglio ( https://mountain-intaglio.com/) and sells plate material and other sundries. Jon Cone also has a studio/Workshops/supply business in Vermont USA.... https://shop.inkjetmall.com/Historical-Process. I would surmise there may be others in Europe offering workshops in polymer photogravure but I really don't know.

To actually make polymer photogravure prints, besides a printer, plates and software, you will also need a UV box with 365 nm sources. The UV lights sold on the internet are mostly 390 -405 nm and while they work fine for Cyanotypes/Kallitypes etc, they will not work for photopolymer as I have learned. The other limiting issue for many is the intaglio/etching press - they tend to be expensive, heavy and take up a lot of room. I have solved this problem by joining a local print making studio which are found in most large cities and has several presses. Also, most university art programs have intaglio presses and access can sometimes be negotiated.

Sorry for rambling on so long, I hope this may have been helpful. Attached is a print I made recently, when everything works the results can be very satisfying.


Dave Najewicz

 
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RogerHyam

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Thanks Dave. Lovely image.
 

Walker Blackwell

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Clay, Jon, and now several hundred other studios and artists are using the method developed by myself and Nathanael (it's different than Clay's book). We teach this and do setups.
 

Graham06

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Walker Blackwell said:
Clay, Jon, and now several hundred other studios and artists are using the method developed by myself and Nathanael (it's different than Clay's book). We teach this and do setups.
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What are the steps you follow?
 

Walker Blackwell

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Graham06 said:
What are the steps you follow?
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Quick overview of what the setup entails:


Four steps for DTP photogravure initial setup.

Plates go through the printer and get MK,C,LK dots. 4:1 ratio of MK/C dots in the shadows for best dMax on Toray plates . . .

1. Exposure test. We use color changing Toray plates (I did a world-wide search when Jet/Miraclon plates ended during covid and found (re-found?) Toray and that is what most people use now for this.
2. Open bite / limiter test (to figure out how many MK dots you can pack into a given area without open-bite at step 1 exposure. This limits the master curve (up or down total ink limit) based on the open-bite curve max density.
3. Initial calibration to a given contrast intent. Generally we do 80x10 averaging targets with an i1Pro2 but it can be any averaging target really . . . our contrast intent is published in various places and DTP softwares now but we worked out a very good transfer curve to match 1:200 monitors in 1:100 mediums.
4. Validation of calibration (same target + and image) to verify that it's all along the line and if not to work out why or iterative a final final curve.

The code we built/use stems from work I did at Light Work doing dig negs. It takes raw spectral values and does the averaging there before converting to Luminance. This allows for extremely accurate measurements of rough prints: platinum, gravure, cyanotype, even silver with falloff, etc.

Warmest,
-Walker
 

Graham06

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Thanks. This will probably help a bit when I pick this up again.
 
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