Up to now, I’ve only been doing single transfer carbon prints. Perfectly fine, but how about doing that other version, the double transfer? I ran a failed experiment a few weeks ago using Yupo as the temporary support. Yeah…that doesn’t work. But then I picked up a magic, very special material that did work…
First, why would I bother in the first place? Single transfer carbon prints are nice enough as they are, you could argue. But they have two notable disadvantages:
1: Single transfer carbon prints are mirrored compared to the original scene. For abstracts and some landscape work, this need not be a problem. In fact, most of the time this doesn’t bother me at all. But for instance with portraits and images featuring text inside the image frame, a mirrored image is mostly not acceptable. At least not to me.
2: It’s very hard to register multiple images on top of each other when making single transfer carbon prints. Perhaps I should even say: virtually impossible (although I’d say it’s probably technically feasible). Anything printed in color necessarily needs to consist of several tightly registered prints, and sometimes this is done for monochrome work as well, for instance to obtain super-smooth tonality all the way from the deepest shadows to the most delicate highlights.
So I thought I should experiment a bit and like I said, I gave it a go on Yupo. This taught me two things: (1) Yupo will easily take a carbon transfer, but it won’t virtually let go of it. (2) Yupo in fact has a very thin laminate film on both sides, and a carbon transfer will stick better to this film than the film does to the actual Yupo substrate. Yep, I learned that the hard way. I takes quite a bit of force to get that surface film off of the Yupo base and it tends to tear to shreds in the process. Interesting, but otherwise not particularly relevant, so I’m going to leave it at this.
Anyway, the other day I was at one of these ridiculously cheap shops that sell Chinese junk. Yes, I’ve said before that Chinese products aren’t all junk, but truth be told, at least some of what this store sells does fit into that category. However, for several things it’s the perfect place and I’ve picked up all kinds of stuff that I use regularly. This time, I thought I’d drop one of those rolls of thin polymer film into my shopping basket; you know, the transparent, crinkly type used to wrap flowers and things. I suppose it’s often referred to as ‘mylar’, but that’s a brand name for a type of polyster film and I frankly don’t know if it’s polyster. I do think so. It doesn’t seem to be polypropylene, which is generally softer and less crinkly. And it sure isn’t PVC. I suppose there are many other things it might be, but some kind of polyster sounds likely.
Anyway, guess what? It’ll happily do a double carbon transfer. Wouldn’t you know! I prepared the film by making a 0.5% (or so, could be much less in fact) gum arabic solution to which I added a few drops of 8% ammonium dichromate. Not my preferred way of hardening, but it was a spur-of-the-moment thing where I prepared the temporary support film as the tissue was being exposed. Hardening with dichromate is pretty quick and it’s what I had at hand. Formalin would have taken longer and would have presented problems with outgassing and consequently fogging the tissue, and I didn’t have any albumen that I could have hardened rapidly with ethanol (I’m preparing some now for similar situations…)
You can see above what the print looked like in the wash after the development bath. Alright, not my finest print, as it’s kind of, well, dark…but it exists and that’s more than I had expected. Much more. The rest of the process was pretty much a textbook job; I dried the print to allow the gelatin image to fully harden. Then I soaked it again together with a piece of final support paper (25g gelatin per square meter, hardened with chrome alum), squeegeed them together and let dry. After two or three hours I carefully peeled off the film, which took some force, but left the image intact.
This certainly opens up new avenues…well, not entirely unexpectedly, but this step is one of the necessary ones I need to get the hang of. It’s nice that it has worked once, but now I need to figure out how to do it reliably. I’m not sure if I’ll stick with the €0.90 roll of polyester film. It’s very flimsy, which makes it awkward to work with. It’s (literally) like handling a print on a candy wrapper. So currently I’m testing some other materials; let’s see how that pans out!
Update: well, that pans out quite well, as it seems. Both materials I tested seem to transfer OK! I had one corner lift that probably doesn’t have anything to do with the temporary support material, as the image otherwise adhered just fine. The materials I just tried are something called ‘montage film’, which apparently is a simple polyester film of about 500um thickness and it seems to come in 50x70cm and 100x70cm sheets. It’s smooth on both sides and has a decent stiffness making it pleasant to work with. That’s all I know about it: just Googled it and found something from Pyramid that might be the same stuff.
The other is called ‘Paterno’ and also comes in 100x70cm sheets, but this is heavier (it feels like it should be around 750um), it’s frosted on one side but smooth on the other and has a slight yellow tint to it. I think it’s polypropylene, but I don’t know for sure. Apparently it’s used for cutting out shapes for quilting. Well, whatever you say – I don’t know the first thing about quilting! All I know is that it seems to be a promising candidate for double transfer carbon alright.
I treated both the montage film and the paterno identically: ran them briefly through a tray with a 0.65% gum solution to which I added a few drops of chrome alum. Hung to dry and blotted away a few of the remaining droplets after a while. I did this again while the carbon tissue drying and exposing, so it didn’t take all that much time. I haven’t done the transfer to the final support yet, but don’t expect any particular problems (I’m probably going to regret saying this).
Update 2: yup, regretting my optimism already. Looks like both images have some reticulation. I chalk this up to the gum & chrome alum subbing, though. It looks like something that could be ironed out.