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Substrates for Shooting in Camera - FILM, Acetate, PET (polyester), Glass, etc.

dwross said:
The UV inks are an exciting development. UV-cure technology seems like near-magic to me.
Click to expand...

The best UV cured product I have seen is the lacquer finishes for guitars. Traditionally, they would be sprayed then left for several weeks before final finishing. Now they can be worked on less than an hour after application.


Steve.
 
Yeah, there are more levels to "surface treatment" than just treated or not treated. Photographic emulsion seems to be very demanding and needs a particularly "good" surface treatment. Some products that are treated for inks, may not work for emulsion. Heck, they don't even work with all inks...

So, for example, there is polyester sheet available that is corona treated at factory to make printing possible. So it seems that the corona treatment is not completely volatile. It remains good enough for most inks, but not good enough for emulsion (and some inks).

But given that 3M product, it's probably easiest to just buy and use it. Do you know of any retailers who sell those with international shipping?
 
For photographic use, corona discharge is considered unusable after about 48 hours. I'm giving our normal guidelines at EK. Therefore I would bombard either in-line (ILEB) or I would schedule bombardment 24 hours before my coating time.

PE
 
daveandiputra said:
Any pointers or links to read about it?
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US 4076772 describes a method of coating gelatin on PMMA (= "plexi"): "A poly(methyl methacrylate) sheet is coated with nitrocellulose, the nitrocellulose is denitrated, and a gelatin solution is applied (...)."
Ammonium sulfide is used for denitration.
 
dwross said:
Hi Steve,

The UV inks are an exciting development. UV-cure technology seems like near-magic to me. I use a UV-curable adhesive to make glass emulsion wells. [/I]
Click to expand...

That's a very interesting.
As an aside, photopolymers (hydrophilic or hydrophobic) based on free radical polymerization, may actually provide improved adherence to a great many kinds of substrates. Free radical formation seems to be the principal reason why corona treatment "works".
 
For the moment I've only been playing around with setting and hardening gelatin, played with the idea of gelatin on it's own, but it tears way too easily.

Making crude cellulose acetate, and dissolving and setting and evaporating it is fairly simple process, you can make whatever thickness you want, but you can't exactly make a roll that way, but you could build a very large trough, or long trough with a sheet of window glass. You can make even better acetates with the addition of acetic anhydride.


Eventually I would like to try my hand at coat with an array of fine spray nozzles over a moving transport through a simple machine, but I don't know yet.
 
That's interesting, the idea of using gelatin or some other colloid as the base (I think collodion's been used in the past too).

The idea of casting one's own base is zany but wonderful. I'm glad someone's thinking about it.

I wonder if there's some modern polymer that you could "cast" in a similar way to cellulose acetate, with better properties.
 
Mark Osterman teaches and demonstrates the making of film support in one of his workshops. It is not all that hard.

PE
 
IIRC, that demo was with nitrocelluose film support.
I have a demo of TAC (CTA) being made and hand coated.
 
I didn't know Mark did that, is it indeed nitrocellulose? It makes sense he'd prefer something flammable...

Ron, do you recall if Jim had investigated this 3M support for his non-staining base?

Would love to know how to make cellulose triacetate!
 
IDK which type of support Mark made. You might ask him. Same for Jim Browning. He tried a number of supports before he settled on the one he did.

PE
 
Denise,

I just wanted to ask you a bit more about the 3M films. This is really a great epiphany; and I think that although you mentioned them on the Light Farm that this is the first place where they're mentioend by specific product name(?).

How would you compare the subbing to DuPont 583 (PF melinex)? Both will be destroyed with pre-wetting of any kind but DuPonts is very resistant to abrasion and even oily fingers (trust me, I tested it... after eating fried chicken... ). How about the 3M stuff?

Also, what size did you get it in if you don't mind me asking? Is it in a roll, or sheets, how long and how wide? Did that company offer any kind of custom slitting or size options? I'm just rather curious about all these bits of minutiae.

Thanks again for bringing this to everyon'e attention; I'm quite excited by it.

edit: Here is a list of potential suppliers.
 
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Actually, I think that poor scratch resistance of subbed films (both 3M and Dupont) are the material's Achilles heel. The Dupont film that The Formulary sells has minute scratches. They're almost impossible to avoid. I'm getting much better at handling film, but (so far) it's a guarantee I'll end up with a scratch somewhere in any given batch of finished film -- usually from the final cutting-to-format stage. I'm pretty religious about wearing cotton gloves, so I can't speak to grease resistance. I can tell you that you don't want to sneeze on the stuff .

The good news is that the scratches are essentially microscopic. (More info: http://www.thelightfarm.com/cgi-bin/htmlgen.py?content=28Nov2011 )

One issue that I'm still working out is that the 3M film doesn't seem to hold dry emulsion as well as the Dupont if the coating temperature is too high. I've got the right temp for my emulsion figured out, but I'm not motivated to test, test, test all parameters, just to obsessively blog, so I'm hoping others will join the Light Farm 'research team' and share their findings. (A girl can always hope.)

The 3M vendors I talked with all would do custom cuts for a price. I never asked about sheets. I think the film is only available in rolls. I was able -- and quite happy-- to take remnant end pieces in various widths -- for both the thin and thick films. I got a great deal that way. My only requirement was that no one roll weighed more than 50 pounds or was wider than 36 inches.

You're right about hydrophilic subbed PET being a game-changer. Seriously, there is now absolutely nothing standing in the way of really, really good diy film, plates, and paper (except of course, the exact same things 'standing in the way' of all non-instant, non-digital photography -- enough time and space to create.)
 
Just want to add a quick note to this thread regarding Dura-Lar Wet Media film. I was at the art supply store the other day, and they had a pack with a dinged-up corner that was significantly discounted. I have no use for it, really, but I grabbed it thinking of this thread. If anybody wants to try it (US only, probably, otherwise postage gets too high), I'd be glad to send out a few 11x14 sheets rolled in a tube, or cut down to 7x11 for mailing flat. I'd ask that you reimburse me for postage and shipping materials. If anybody's interested, let me know via PM.

I took a little corner of it and ran it under water. There is definitely a clear coating that got a bit slippery for a second before it rinsed off. Have no idea what it was. The highlighter markers that I had laying around (which I thought were water-based) didn't behave any differently between the wet media film and regular dura-lar, so maybe they weren't water based, or...

Anyway, just wanted to mention this. If it works, it might be a good option for those who wish to avoid the larger purchases required for the 3M film if you're making sheets.

--Greg
 
Greg, funny you mention this. I emailed Grafix a week or two ago asking about the wet media film with gelatin and they were intrigued, so they sent me a couple sheets to test. Just arrived today!

I only say something to account for why I won't be raising my hand, but dang what a coincidence.
 
I was wondering -- I use imagesetter imaging film in a small offset printing business that I have. Often the film gets messed up (someone forgot to proof the page, etc). If I bleach the emulsion off of the films that cannot be used to make printing plates, will the substrate that remains be suitable for coating with emulsion without further preparation?

This would mean that instead of the used film being hazardous waste, the bleached off emulsion would be, and I would have to figure how to dispose of it, but the clean substrate could be used for coating if I ever get around to making my own emulsions. And I have quite a lot of the stuff.
 
Well, if you literally bleach off the emulsion, probably not. But, if you bleach out the silver, then the remaining clear gelatin will make an excellent substrate. So yes.

But most subbing layers on film are one-and-done. For instance, if you wet the Photo Formulary melinex before coating, it becomes useless. That's why I say that if you literally mean removing the emulsion from the film, then the remaining raw PET/TCA will probably not accept a coating.
 
OH - OK - thanks for the explanation. I had read some of the threads here but only quickly, and I had thought that the subbing process modified the surface of the plastic to accept an emulsion, in a way that would permanently affect the plastic. I did not realize it only worked once! I was talking about removing the emulsion - I thought that bleaching and fixing the existing emulsion could be a bit costly, but it is worth considering. Ferri bleach and fixer do last rather a long time.

But wouldn't adding a new emulsion make the resulting total gelatin layer(s) rather thick?
 
I suppose adding a new layer would make it somewhat thick, but not necessarily too thick. Any machine coated film is going to have a rather thin coating to begin with, so it shouldn't add much more than several microns.

As for their subbing treatment, having to guess here, I would bet that they coat with an inline corona discharge unit. The pre-subbed substrates on the other hand probably receive a corona treatment, and are then treated with an ultra-thin subbing layer for coating later.
 
Some subbing layers can work more than once. I would not vouch for quality though due to induced imperfections.

PE
 
If I did remove the existing emulsion with chlorine bleach, could the remaining substrate be re-subbed?
 
Probably not at this point. It would have to be re-bombarded with a static charge. That is, if the subbing is gone.

PE
 
I'm posting this just for reference; a technique for treating raw PET with potassium hydroxide to roughen its surface texture and thus create a hydrophillic subbing. Umut came across it.

Translated from Fiziko-Khimicheskaya Mekhanika Materialov, Vol. 12, No. 2, pp. 118–120, March–April, 1976. By I. Astrina, S. V. Vlasov, R. D. Gorak, Yu. V. Moiseev and Ya. A. Serednitskii

http://www.springerlink.com/content/kgwn7n442v57u30q/
 
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