Dry plates with acryllic or polycarbonate base

Falkenberg · 05-14-2008, 12:38 PM

Has anyone tried the combination of liquid emulsion and acryllic plates or polycarbonate plates. There are several plastics on the market that are transparant and cheaper than glass. they are also easier to cut. But can they work as a base for dry plates ?

Falkenberg · 05-17-2008, 03:55 AM

I have had contact with a danish company that sells plates in many different materials and they will try to find out wich will work.

Kirk Keyes · 05-17-2008, 12:56 PM

I don't see a reason it would not work. The emulsion may stick to the plastic a little better even, with all the static that plastics generate perhaps that would help.

Murray@uptowngallery · 05-17-2008, 01:23 PM

I know you are into ULF, and if cost is an issue, I assume you are implying somethign larger than 4x5?

For anything larger than, arbitrarily, 4x5, I'd be concerned about flatness, rigidity, etc. It flexes pretty easily and while it may have been due to the protective paper (although it is on both sides), I have seen acrylic that did not sit flat.

I previously had concerns about using it for viewing in view cameras...same physical issues for using it as plates.

An experiment with a small piece won't cost much & may work just fine!

Murray@uptowngallery · 05-17-2008, 01:28 PM

I find acrylic & polycarbonate in 1/8" to be much more costly than glass...must have something to do with petroleum prices

Ian Grant · 05-17-2008, 01:37 PM

The secret is going to be hardening the emulsion, so there's less chance of it frilling at the edges and beginning to lift off. That's assuming you can coat it evenly in the first place. The surfaces of acrylic and polycarbonate are quite different to glass.

On a small scale I'd use an airbrush to spray a very fine gelatin subbing layer onto the surface first, with a small amount of Chrome Alum added to it. I experimented with applying emulsions to a very wide variety of surfaces just over 30 years ago. Later on a commercial scale where necessary we sealed the surface with an acrylic lacquer, then used 600 grit wet & dry to prepare the surface before applying the emulsion. I wouldn't advocate that for negatives but it works extremely well for prints,

Ian

eclarke · 05-17-2008, 01:43 PM

Check for clear, rigid polyester sheet. Some film base is polyester..Evan Clarke

jnanian · 05-17-2008, 01:47 PM

i have a few plates i coated with liquid light a while back.
they are plexiglass, and i used polyurethane as a subb.
they LOOk fine, but i haven' t exposed+souped them yet.

i will report back when i do ..

--john

richard ide · 05-17-2008, 02:54 PM

I would recommend that you use a plastic sheet which is cast rather than extruded. Cast acrylic is readily available. I think most other plastic sheeting is extruded. Extrusions will change dimension over time due to creep. I wonder what sort of pricing you could get from a glass company if you stated your purpose and maybe bought a dozen sheets at a time. If you specify "select" quality you should get pieces with no discernable flaws. Cutting glass is very easy and use sandpaper to touch up the edges.

dwross · 05-27-2008, 01:35 PM

This thread got me interested in the different possible coating substrates. Actually, I like glass just fine. It's cheap and easy to handle and reusable. I never have managed to reuse a piece of acrylic when it's been required for hanging in a show or gallery so I don't think it would go well for plates either. And, at least around here, it's darned expensive.

After glass, the Melenex subbed film that the Formulary sells works great. I've been working through a couple of packages. The surfaces are scratched from the cutting technique they were using, so I won't be able to use the negatives for exhibition, but it works just fine for experimenting. I can only hope they get the cutting problem solved soon. That's the reason the Melenex is listed as 'out of stock'. I can't imagine how busy they are getting ready for the workshop season, but maybe if a couple of people besides me nagged them about it...

Back to the acrylic, though. I set the Melenex on thick sheets of plexi for support during coating. The emulsion that spills over seems to stick just fine to the acrylic.

One more item: In what is proof positive that the greatest theoretical idea can be oh so very dumb - don't bother trying to coat Pictorico OHP. It seemed like a natural when it came to me in the middle of the night. Nope. Doesn't work. Really doesn't work.

Happy cooking,
d