Using indirect gelatin resist as a tissue for Photogravure

[Jack Whitwell]

Over the past couple of years I’ve been working away trying to figure out copper photogravure. Thanks to a lot of help from this forum!

Being in the UK, I’m yet to bite the bullet and order some of the cape fear tissue. Instead, I have been making my own pre sensitised DAS tissues and normal for dichromate. The workflow is slow and inconsistencies in the tissue and pigments is causing problems.

I came across some of the indirect films whilst researching tissue manufacture. Autotype still make the popular five star gelatin film that is pre-sensitised. Has anyone experimented with it?

from what I have read it has a clear back - for screen, you expose the neg to the clear acetate which allows development prior to mating onto the screen. They use a activator agent - from what I gathered this is a hardener so for this purpose that stage would be omitted. The main benefit would be the fact that it’s presensitised with a diazo sensitiser.

I know pigment density along with the amount of sensitiser will have an effect on tissue height and contrast - but with digital negs and multiple acid baths I think I may be possible to work around this. If it works…

Any insight before I possibly waste a lot of time would be brilliant!

Jack

 

[koraks]

This sounds interesting, and you're making me curious, albeit more at a theoretical than a practical level. Forgive me the perhaps silly question, but you mentioned this:

I know pigment density along with the amount of sensitiser will have an effect on tissue height and contrast

I get what you're saying here, but I don't connect this with photogravure. It sounds more like carbon-transfer talk to me.

Having done photopolymer intaglio as well as carbon transfer, I am aware of the (potential) overlap between both processes, but I have never proceeded to the stage of copper plates and instead stuck with polymer plates for the intaglio work. All digital-based, so no real aquatint/rosin box or film-based screens or anything.

I did consider using a photopolymer and mating it onto copper plates and then etching the copper that way. Like I said, I never went that route, but wouldn't that be by far the easiest solution for you as well? I know many people today work that way and materials are relatively easy to get. Photopolymer is a breeze to work with compared to gelatin. And it's sensitized 'by nature' anyway. For intaglio work, exposure isn't very critical since you're only talking halftone and no continuous tone; given a decently collimated/point light source (this is the critical part!!), there's a lot of leeway.

Perhaps the essence of what you're doing went totally over my head; in that case, please explain a little more about your printing approach.

 

[Jack Whitwell]

Hi Koraks,

Thanks for your reply!

Yes I’ve got to grips with photopolymer and I have achieved pretty good results. However I love the process of etching the copper plate and aquatint. I like how you can control the curve during development, push and pull the image e.c.t.

It is a carbon transfer yes, that is the makeup of the resist for photogravure. The varying heights of gelatin allows for different tones due to the time of absorption of the ferric. (Sorry if I’m stating the obvious haha!)

 

[nmp]

Hi, Jack:

Have you looked at the DTP process? It's something I would love to do (sometime in distant future, though.) Seems simpler compared to the classic process having eliminated the use of digital negative altogether with no transfer or mating required.

http://www.photopolymergravure.com/dtp.html

You can buy the plates here:

https://solarplate.com/

:Niranjan.

 

[koraks]

It is a carbon transfer yes, that is the makeup of the resist for photogravure.

Yeah, I understand; I am/was confused about your mention of pigment though, since it's technically not needed for photogravure. But I suppose you put it in to be better able to see what you're doing?

Yes I’ve got to grips with photopolymer and I have achieved pretty good results. However I love the process of etching the copper plate and aquatint.

Perhaps you missed the point of my suggestion: you can use photopolymer film just like gelatin tissue. Laminate the photopolymer onto the copper plate, expose polymer, develop polymer and then proceed to etch the copper. Strip the photopolymer afterwards.