Vacuum Frame - Photogravure work

[Mac064]

Hi there all,

This is my first post to Hybrid so I hope it isn't a daft one. I want to do some photogravure work using photopolymer plates and digital negatives. Although maybe not the most popular process (maybe becasue of the need for an etching press, plates, inks etc) I want to give it a go and have done a fair bit of reading up on the process. One thing that many practitioners mention is the need for a vacuum press to make sure that the contact between the polymer plate and the negative (and indeed the aquatint screen if you use one) is as good as you can make it. Many (if not most) therefore reccommend highly using a vacuum frame. I don't have one and do not have access to one either but I was wondering how much degredation there is when not using one. I assume that in the heady days when photogravure work was at it's height Alvin Coburn, Demachy and the greats did not have flash vaccuum frames either (or did they?) and they produced work that was hardly shabby! In my other alternative process work, I have used very heavy plate glass or vintage split back contact frames which have been fine for my purposes. Anyway, before I start cutting the polymer plates and giving it all a go I just wanted to ask out in the community if anyone had a similar problem to tackle and the results they achieved.

Thanks for your consideration.

 

[Loris Medici]

Back in the days of Alvin L. Coburn etc., I think, they were printing under sunlight (or carbon arc or something like that). Since sun (and carbon arc and such) is a point lightsource, the requirements were a little more relaxed. If you're going to use a UVBL lightsource, I don't think you'll be able to do extra smooth prints w/o a vacuum frame. The modern plate-burners (like NuArc 26-1KS) have vacuum frames and semi-collimated lightsources - for a reason, methinks...

In short, you need very good contact (possible with vacuum frames only) if you're going to print at high screen resolutions using an artificial lightsource!

BUT all this is theoretical information, I'll leave my place to people who actually do photopolymer gravure now!

 

[iansand]

Loris is correct re. the single point light source
With UV tubes the light is coming from different directions and without a tight contact will spill around you image.

If where you are is like here in France with printers going out of business, you could probably find a vacuum unit or printing down frame at a reasonable price

 

[Mac064]

Thanks for the responses guys, I appreciate your time. I guess the only option for me quickly is to work without a vacuum frame and see the effect. I am not one for crisp, sharp images per se and I like the misty atmospheric feel of the early photogravure work anyway. I will look around, though, for a vacuum frame if one comes along (I know that new they are not cheap), there have been times I really could have done with one. I may also try to see if using a split-back contact frame is possible becasue the polymer plate, despite being steel backed is not actually that thick. Guess I have to be careful I don't crack the glass though!

Thanks for the help.

 

[Loris Medici]

Good luck!

Be prepared to face the need of decreasing screen resolution / increasing dot sizes and also experience mottled shadows (plus open bite) and mottled smooth areas...

 

[PVia]

What's the sun like where you live?

In parts of the world, sunlight can be very dependable and much, much quicker than artificial sources.

 

[clay]

I do polymer gravure and I can assure you that you will need a vacuum frame and a point source light to get consistent results. Even with that, you will have to be extra careful with the positive in assuring you do not get Newton rings. I spray the inked side of the positive with a light coat of Krylon acrylic which gives the positive a small amount of "tooth".

It is a beautiful process, but is not nearly as easy to learn as pt/pd.

 

[clay]

I'll add some additional thoughts about using print frames - I just gave a two day class at Basho on polymergravure, and we did not have access to a vacuum frame. We spent 3/4 of the first day fighting contact problems with the split back printing frames. For instance, did you know that glass that looks flat is sometimes not?

The issue is not sharpness. The issue is that anything short of perfect contact between either the aquatint screen or the positive will allow light to hit the highly reflective plate and bounce sideways onto other areas of the plate. And what you end up with are overexposed light patchy areas running through your plate. It is maddening.

I strongly advise against starting this process until you have a good point source light and a vacuum frame. It will be an exercise in frustration otherwise. You'll spend loads of money on plates that end up in the trash. I speak from painful experience on this.

 

[Loris Medici]

And a note from me, regarding the "old timers" issue:
Back in the days of Alvin L. Coburn et. al., they were doing traditional photogravure. You don't expose a hard material (such as photopolymer plates) with trad. photogravure, you expose relatively much softer and flexible carbon tissue. (And later transfer it onto the copper plate and etch with ferric chloride...) It's easier to have good contact with carbon tissue, especially when compared to the hard, relatively non-flexible metal polymer plates...

Regards,
Loris.

 

[Mac064]

Thanks guys for all the great comments. You have all convinced me that the vacuum frame is the only way to go. I have just joined a great local print workshop and lo and behold they have a point source UV vacuum frame which is ready and waiting for me. The screen printers use it a lot. All I have to do now is work out the exposure times for the Toyobo plates and give it a go. I know that it will be a slow learning process, so I aim to start with small plates and get to grips with the exposure and processing of the plates. I will waste some plates I know but that's the way of learning I guess. Thanks for the support and I will let you know how it is going.

 

[michael9793]

try this site they even have youtube movies to help.
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