Saturday, July 16, 2011

Bromine Gas Bleaching Test #1

Thought I would post an update and share what happened a few weeks back.

Disclaimer: Needless to say Bromine, especially gas/vapour/fumes etc (and other halogens) is very dangerous. Don't do what I do.

So I pulled film out of the bromine gassing area into light, and then gassed it again to bleach away light induced fog, 'cept I left it in there for over a week to let the bromine escape and dissipate completely..

Anyway, the reels I used in the tank (apart from bottom one, which was touching acidic+oxidising solution) have bromine deposits, as did the film.. which was kinda half melted somehow. Awesome!

I'll try bromine chlorine first.. as it's a gas at the working temps I use, rather than bromine which has a boiling point of 58.8 C (above my working temps, hence it will deposit back onto surfaces at room temp). Though I'd love to try Iodine bleaching as a method of not only removing fog, but restoring ancient film to full speed, and even increasing speed depending on iodide content already in the film.



My Theory On Gas Bleaching:

My theory with gas bleaching is that I can rehalogenate silver to silver halide with a gas bleach.

You can do this in solution with a bleach, but this will wash out sensitising dyes, anti-halation layer, and other things, which reduces film speed and film spectral sensitivity.

With gas bleaching, that stuff stays where it is, hence you can potentially recover full film speed, or even potentially increase film speed of both b&w and colour film that has been fogged due to age, or film that has been pulled out in the light.

You could go so far as to leave film out in the sun to reduce to finer silver grains, and gas bleach back to silver halide, for a much finer grained (and very high resolution!) slow speed high contrast film - this can be applied to colour films too!

It doesn't take much halogen gas at all, so it can be performed in a film tank easily to sit in a small amount of gas, bleaching goes by very fast from what I can see.

More testing is needed.

Wednesday, June 29, 2011

Colour Print Film Split Bath Experiment Part 1


So I got 1000ft of Vision Print Film I intend using for pictorial purposes. It is process ECP-2B, which is CD-2 based, I have dry CD-2..

As Jon Irenicus would say; "It is time for more... experiments. The pain will only be passing; you should survive the process."

This is the third test and first one worth showing.

The recipe I used is as follows;

Bath A:
7g/L CD-2
9g/L Sodium Sulphite

Bath B:
40.5g/L Sodium Carbonate
1.0g/L KBr

Both images shot in unfiltered heavy indoor tungsten.

The 50D ain't too bad, the density range for the layers on the 50D is right in the middle, a little thin on the range but pretty reasonable, of course it's a real low contrast scene and low contrast film, it would probably excel for a high contrast situation outdoors.

On the print film, all the layers have a wide range, cyan and magenta have the lowest dMin starting at nothing basically, but the range is pretty good, dMin and dMax together should be higher for better quality, dMin is slightly high on the yellow layer, and dMax a bit too high.

Future tests will increase the amount of CD-2, KBr, and I would add KI if I still had some.. would be very nice to. Oh well, benzotriazole and phenidone in Bath A are also on the list.

Once I get a good formula, I may compare it to a CD-3 version instead (ECP-2 is CD-2 based, ECN-2 is CD-3, E-6 is CD-3, C-41 is CD-4) to see the difference on the print film (ECP-2 film).

Print Film Test #3

Monday, June 6, 2011

Film Re-cycling Experiments Part 1.

After ripping out 70 odd ft of Vision1 500T (15 years old) out of a bulk loader and sitting it on my floor in the light (to make room for new Vision2 50D and Vision3 500T for bulk loading... still got another 700 ft of Vision1 500T in cans), I thought of something to do with it.

Cut some of it up, loaded it in a tank, processed it in some Xtol, now then I chilled a weak solution of potassium ferricyanide and potassium bromide to bleach the film back to all silver halide (just silver bromide) slowly to make a high contrast, fine grain, slow speed b&w film.. though I can try putting it through C-41 to get the CMY dyes (wont be a real colour image, but can treat it as a b&w during scanning for chromogenic b&w for IR dust removal), or just regular b&w processing.

The stuff still in the can and old expired film sitting around I have that's now shitty quality (Kodak Gold 100 from 2000), I can try just bleaching the fog (specks of elemental silver) away back to silver halide to restore the speed and denisty range.

If I want to keep it as useful colour film, that will have to be gas bleaching, so that it doesn't wash out the anti-halation layer and the spectral sensitisation dyes etc.

I also figured I could bake some film out in the sun until it is all reduced to metallic silver, and gas-bleach it back to silver halide for a high contrast, fine grain, slow colour film.

Saturday, April 30, 2011

Kodak Australia Helpful

Left a message on the Kodak site U.S. asking the difference between 5219 (Vision3 500T, and 5230 (500T, as it was newly listed with a newer data sheet.

Received a phone call from a Kodak Australia rep (Fuji Australia last year or the year before I had to chase down numbers which most were no longer working it seemed..) explaining that 5230 is basically Vision2 (iirc) and lower cost and aimed for TV dramas etc etc. with a more limited format size and length range. He was quite helpful and enthusiastic

5219 is still the latest and greatest 500T. It comes in 100ft spools.. so it's ready to bulk load, so I dont have to buy a 400ft core and rewind by hand into a bulk loader.. which takes some damn time last time I tried.

50D comes in a 200 ft core at the smallest size.. which isn't too bad, I'd like to try that too.

And also 1000ft of 65mm.. to trim down into my saved up 120 spools and paper.

Monday, February 28, 2011

New Portra 400... overexposed 5 stops?? ISO 12.5??


So on one of our photowalks in Melbourne city, I incident metered for the shade, as most of my subject as in the shade and wanted to optimise exposure for my subject, this is an extra +5 stops compared to a subject in the sunlit areas... yet it handled this mixed shade/sun combination beautifully, and flattened out the lighting contrast and did not get too dense, tones are reproduced beautifull for subjects both in shade and sun, it handles such a extreme harsh contrast condition wonderfully.. I have midtones for both!

The New Portra 400.. it has fine grain.. it is very sharp, it has wonderful saturation, and a ton of local contrast snap, very good skin tones.. it is high speed.. it is pushable.. it handles overexposure, it retains highlights, it can compensate high contrast with increased exposure without pull-processing.. if you had to have only 1 colour film, this would be it, forget Ektar, you can do everything with this.

If I was shooting for the sunlit area.. you would call this an EI of 12.5! This isn't a pull-process either, it is standard.

First 10 people in Australia to Like my services page, get free C-41 processing and web size scanning of a single roll of 35mm or 120, includes cross-processing and an pull/push you wish to have done.

Portra 400 pushed to 1600

New Portra 400 pushed to 1600.. that's 4 minutes 15 seconds in C-41 developer :)

This new film is beautiful and it handles excellent at 1600.. as long as you push it though!

Though there is invariably going to be a couple of times when a bit of underexposure will be introduced, so perhaps a push to 3200, but using an EI of 1600 for exposure would be best, or push to 1600 with an EI of 1250 or 1000 even better.

Portra 400 @ 1600

First 10 people in Australia to Like my services page, get free C-41 processing and web size scanning of a single roll of 35mm or 120, includes cross-processing and an pull/push you wish to have done.

Portra 400 pushed to 25600

Pushed 6 stops. 7 minutes and 30 seconds processing time in Flexicolor C-41 at 39 degrees celsius.

Density range is thin, image is poor, and lots of scanner noise present. It's at this point several things spring to mind:

1. Use a fast lens to begin with (well I just need the $ for that Mamiya 645 80mm f/1.9!)
2. It's at this point, the mercury vapour and hydrogen peroxide latensification looks attractive.
3. Perhaps a tiny pre-flash.
4. A "pre-developer" if you will for about 1 minute or so, phenidone-ascorbic acid speed enhancing developer, long enough to begin to have action, without making a visible image, just to amplify the silver image a bit, in case C-41 can't discern as low intensity sites as a speed enhancing b&w dev can. Which then can be then processed through C-41 after.
5. Rehal processing, after bleaching, instead of fixing, run it through C-41 again to increase dye gain.
6. Combine hydrogen peroxide with a colour developer or C-41 during development to gain more dye yield.
7. Combine points 2 through 6.

Anyway, here is one of the images, probably the best off the roll. I do not recommend this. A push to 6400 might be doable to a good quality, the 3200 results I've seen online are quite good, I think a push to 6400, but shot with an EI of 3200 might be best though.

First 10 peoplein Australia to click Like on my services page get free C-41 processing and web size scanning for any 35mm or 120, including cross-processing and/or push/pulling (still need to get your film to me and provide return postage if you're not local).