Film For Autochrome Project

[htmlguru4242]

Finally! I've made up a screen plate for my autochrome experiments from corn starch dyed with sharpie marker dyes. It is not very good, but it'll do for rough experiments. I'm going to make another today (hopefully more prescisely) and I'm hoping to test it soon.

I'm going to try to register the mask to the film, expose, process and re-register. I'm not going to do this in-camera as of yet; I'll be making contact prints from some old slides.

What I need are reccomendations for inexpensive sheet films that have good exposure latitude, medium to medium fine grain and reversal-process well (and have a clear or almost clear base). Any and all reccomendations wuold be appreciated.

Thanks!!!

 

[Donald Qualls]

Fomapan 100 in 9x12 cm would be my first recommendation. It's got excellent latitude, pushes well, has quite nice fine grain if processed in the right developer, reverses well (according to Zhenya, aka Eumenius, who's been doing a lot of it) and the 120 and 9x12 cm have a clear base. Oh, and it's inexpensive, around 50 cents a sheet in 9x12 cm from J&C Photo. FWIW, I just processed a test today on Fomapan 100 that appears to have resolved around 100 lp/mm from near the center of field with a pre-1926 Tessar; grain is invisible at 2400 ppi scanning resolution.

 

[htmlguru4242]

Thanks, Donald. That's CHEAP; $25 for 50 sheets; I'll give it a try.

I'm still working on creating a good mask for the autochrome screen that is nice and even, so once that's done (should be soon) I'm all ready to go. My second test came out ok, but it is green insted of neutral gary AARGH. The exposure latitude that you say the film has will be great for this, as I do not know what the screen's filter factor is.

Then there's the fun of registering the filter to the film in the dark and re-registering it after development. I'll post results when (and if) I finally get any.

Is anybody else working on this?

 

[jd callow]

Still lurking!

 

[Photo Engineer]

Thanks, Donald. That's CHEAP; $25 for 50 sheets; I'll give it a try.

I'm still working on creating a good mask for the autochrome screen that is nice and even, so once that's done (should be soon) I'm all ready to go. My second test came out ok, but it is green insted of neutral gary AARGH. The exposure latitude that you say the film has will be great for this, as I do not know what the screen's filter factor is.

Then there's the fun of registering the filter to the film in the dark and re-registering it after development. I'll post results when (and if) I finally get any.

Is anybody else working on this?

Reregistration of a colored dot pattern at the micron size is going to be a very big challenge.

I have been contacted privately by 2 other individuals who are either doing this or know someone doing this. Unless you are one of them under your own name......

In any event, a while back I gave you the name of someone peripherally involved in this as well, so there is a small select group of people out there involved in Autochromes in some fashion. There is work going on in France and I am somewhat kept abreast of that.

PE

 

[glbeas]

I'm still working on creating a good mask for the autochrome screen that is nice and even, so once that's done (should be soon) I'm all ready to go. My second test came out ok, but it is green insted of neutral gary AARGH. The exposure latitude that you say the film has will be great for this, as I do not know what the screen's filter factor is.

Then there's the fun of registering the filter to the film in the dark and re-registering it after development. I'll post results when (and if) I finally get any.

Is anybody else working on this?

I wouldn't rule out a screen because of a color cast, you will be overcoming the films color sensitivity curves as well as the actual transmission characteristics of the screen and it may well be you will have a color bias without the film in place that goes away when the image is registered. That said I doubt the color cast would be as bad as what you describe. You have a scanner that will handle your results? It'll be neat to see what you turn up.

 

[htmlguru4242]

PE, I've only contacted you via PMs on htis site using my user name here. My real name is not out there are all I don't think ...

Anyway, Gary, I have access to a scanner that will scan this OK. It's an old UMAX scanner with a cold cathode light / diffuser covering the entire lid, and, as such, it can scan transparency materials up to 11x14. The other option, which works is to place the plate / film on an overhead projector and photograph it from the projection screen d-g-t-lly and then transfer it. I've done both with 4x5 slide film and the results are useable.

I'll keep y'all updated; when i get results, i'll post something. I currenlty only have 4x5 Ektachrome around for sheet film, so I'll have to get somethign else before proceeding. I'm just waiting until I ned a big order from J&C, as I don't want to pay shippingofr only one item. On second though, would a sheet of the Ektachrome developed in B&W reversal work ok? because I can use an old box expired in 10/99 for testing in the interim.

 

[Donald Qualls]

Ektachrome processed in B&W reversal might be okay -- the yellow filter layer is colloidal silver and will be removed in the bleach step, so you should get clear base, fine grained B&W images. You'll have the silver exposed through various filter grains at different depths in the emulsion, which could cause (random, bizzare) color shifts as viewing angle changes, but that shouldn't be an issue for light passing through normal to the film surface, and might not be an issue anyway at reasonable angles (the emulsion is pretty thin).

There's certainly something to be said for trying with something you already have on hand...

 

[htmlguru4242]

Ok, but now what reversal chems. to use?

I'll try that.

Now to get the reversal chemistry. Would people reccomend a Dichromate or Permanganate bleach?

 

[Donald Qualls]

I've heard a few opinions lately that dichromate gives a cleaner result than permanganate, and there probably isn't a whole bunch of difference in the difficulty of obtaining either one. The dichromate raises some issues with proper disposal, since it's a known carcinogen and if you're in California it's probably illegal to discharge in waste water even in milligram quanities -- which means your bleach and clearing bath have to be disposed of as hazardous waste ($$$). Unfortunately, the simple route of using E-6 or C-41 bleach won't work, as they just rehalogenate for removal by the fixer.

You'll need sulfuric acid or sodium bisulfate for the bleach, also, of course, and sodium sulfite (or HCA) for the clearing bath.

You might check what it would cost to get the Kodak T-Max reversal kit -- it's got everything you need in one box, and the only adjustments you'll need are first dev time and EI to shoot the film at (which latter you'll be experimenting on anyway because of the filter factor of your dyed starch).

 

[htmlguru4242]

Well, here in Connecticut, i don't think that dichromate disposal is a problem. And, if I need to dispose of it as hazardous wase, i can always put it in a jar and drop it off at one of our local "hazardous wase disposal days" at the local dump.

The dichromate is expensive, but that's ok becuase i don't think that I'll need a huge amount. The TMax reversal kit is quite costly, so I don't think so, anyway, I like the do-it-yourself nature of things ...

Isn't the sodium sulfite just Hypo Clear??

 

[glbeas]

Might try some tray cleaner. Stuff works if you get the right kind. Heres a thread on the subject:

(there was a url link here which no longer exists)

 

[jd callow]

Might try some tray cleaner. Stuff works if you get the right kind. Heres a thread on the subject:

(there was a url link here which no longer exists)

I have 3 or 4 bottles of this I would be willing to donate.

 

[Donald Qualls]

Tray cleaner won't work for B&W reversal; it's a rehalogenating bleach with incorporated fixer, essentially similar to Farmer's Reducer. Problem is, rehalogenating means you can't tell what was originally image silver from unexposed halide, and fixing both away will leave blank film.

 

[glbeas]

Tray cleaner won't work for B&W reversal; it's a rehalogenating bleach with incorporated fixer, essentially similar to Farmer's Reducer. Problem is, rehalogenating means you can't tell what was originally image silver from unexposed halide, and fixing both away will leave blank film.

Depends on what kind of tray cleaner you get. Mine is the Kodak tray cleaner which is sodium dichromate and works quite well with B&W reversal. You have to check and see what kind of tray cleaner you have before deciding whether to use it. Not all brands will work.

 

[Photo Engineer]

The original straight tray cleaner was dichromate with sulfuric acid which is not a rehal bleach. So, it depends on the contents of the cleaner.

Dichromate and sulfuric acid was the cleaner of choice in organic chemistry labs from year 1. Wonderful stuff. When dicrhomate became a no-no, we changed to iso-propyl alcohol mixed with potassium hydroxide. This was about as good. IDK about using it with photo equipment and it certainly isn't a bleach, but it sure does clean glassware.

PE

 

[Donald Qualls]

Okay, cool -- Kodak tray cleaner as reversal bleach, good to know. Is this a currently available product? Is there an analogue product sold for stuff like minilab maintenance/cleaning?

 

[Photo Engineer]

Okay, cool -- Kodak tray cleaner as reversal bleach, good to know. Is this a currently available product? Is there an analogue product sold for stuff like minilab maintenance/cleaning?

Donald, I was only commenting on a very old cleaner formula that we used in the lab, but I have no idea what the current formula contains when purchased from any manufacturer. AFAIK, Kodak no longer sells a tray cleaner outside of the company. Within the company, they no longer use dichromate anyhow.

We had a glassware cleaning unit that cleaned our glassware and they used special industrial strength glass and stainlesss cleaners designed to work with chemicals. I was fascinated by it, as my office was right next to their big cleaning operation. It used a huge automatic machine that looked like a restaurant dishwasher but used lots of other stuff to clean the labware. One of their solvents was DMF (Dimetyl Formamide).

I would test the dichromate tray cleaner first to see what kind of bleach it is from whatever source I got it. Or, you could always mix up your own.

PE

 

[jd callow]

Here is what I have:
Name: Liquid Developer Sytem Cleaner Concentrate
Size: 16fl oz to make 6 gal
Ingredients: Sodium Dichromate and Sulfuric Adcid
Cat#: 101 3176

 

[htmlguru4242]

Mrcallow, that's perfect. And 6 gallons per container is quite a lot.

 

[glbeas]

Okay, cool -- Kodak tray cleaner as reversal bleach, good to know. Is this a currently available product? Is there an analogue product sold for stuff like minilab maintenance/cleaning?

Gainer commented that the Edwal cleaner is a dichromate type, so try researching that direction.