anyone know how to make 4x5 B&W cut film

[kymtman]

How much different would it be to make negatives from plastic sheets,

than make glass negatives. At todays prices I am inclined to try.

I want to know if anyone ever tried this. In glass plate making you

first subb the glass with a gelatine thin base with plain gelatin at

the grocery store. then with the final coat You use a more refined

gelatin and silver salts recipe that you can find on the net, I'll

try to get the web address if anyone is interested. I read the

formulas for three different asa speeds, didn't seem to complicated.

find most chemicals at the drug store.... once I made gun powder when

I was just a lad. Almost blew up the place!!! Love to hear from

anyone interested in making their own negatives.

[kymtman]

Went back and found the web site

 

http://www.darkroompro.com/darkroom/formulas/emulsion/plate.html

[art_haykin]

>>>>"make negatives from plastic sheets, than make glass negatives."<<<< By 'plastic sheets,' do you mean regular film, or home coated plastic sheets? Either way, how do you propose to go from these to negative glass plates? You'd need an interpositive, unless you can figure out a way to reverse process the glass plates. Besides a lot of bother, what do you hope to achieve? Good luck.

[wayne_firth3]

I would guess that coating film would not be too much different than coating glass. Except for saying that you did it, I wouldn't think that, as a photographer, it would be a fun or useful project. For a scientist or a tinkerer it might be interesting. I have one suggestion, however. Kodak makes a product called roller transport clean up sheets that might be useful to you. They are a polyester sheet coated with gelatine. They are used to clean processing equipment. The polyester is dimensionally stable and the first coat of gelatine is already firmly attached. You might ask this question on one of the alternative photo lists.

[jay_de_fehr]

As an economy, well, it's not, but if you're interested in emulsions this is an excellent start:

 

http://rmp.opusis.com/documents/photoemulsions/photoemulsions.htm

 

enjoy.

[jnanian]

ron:

 

i used to do this all the time with liquid light. it isn't quite the same as film emulsion,

but it is fun just the same. i made plexi & glass plates as well as paper negatives and

acetate negatives. its fun to placy around with :)

 

- john

[kymtman]

It's good to know that I am not completely crazy, but at 62 what can one expect. Where did Eastman get his plastic film material. I did not know that it was made at that time!! I wanted to at least try to do this process, just to know that I can. This is America. We do things just to satisfy, don't we? I have 21 grandchildren and they are amazed at the things that I do, and that is a reward in itself.

I have a question about the gelatin coated polyester, is it clear?

I have another project I am working on, applied for a patent pending on it, a new type cut sheet film holder and a developing tank to develope the film in without taking the film out, tested superbly and should start mass production before winter starts, also a new tank to develope ready loads in without the strip down, I'll post as soon as I have a few ready. anyone interested give me a reply.

[j.w.]

There's been a lot of message traffic over the last year on this forum regarding issues of accuracy and depth of focus at the film plane, and I suspect film flatness in the holder is a contributing factor.

 

Being that LF originally used glass plates, I wonder how much better DOF can be in LF when using glass plates.

 

Maybe you'll have the opportunity to test it out along side cut film.

[wayne_firth3]

Ron,

 

Yes, the polyester film is clear and it is coated on both sides with gelatin. I wonder if one side could be coated with the sensitized emulsion and the other side stained with a dye for an anti-halation coating which would wash out in the process.

 

BTW, Eastman's first films were nitrate based using colodion which was cast in large pieces on large tables. Later a large drum was used to cure the product so that continuous pieces could be made. This material is the infamous explosive nitrate based film that was in use as late as the 1950's. The next step was acetate and then polyester.

 

There is no telling what can be learned when reinventing the wheel.