processing rvnp ektachrome

[R Paul]

Hello there
On the big auction site there is a bunch of High Speed ektachrome, which is process rvnp. Now my question is this. Can I use light exposure to reverse the film before the color developer? Now I would be using the solutions from the Kodak MP manuals,either from process RVNP or VNP,depending on which is easiest to mix, I just see a problem with the Ra-1 reversal agent,so if I can get around using it, I'll be happy

Thanks
Rob

 

[Rudeofus]

I have no experience with RVNP process (therefore my late response), but have done a fair amount of homebrew work with E6. I see no reason why light reexposure shouldn't work, but you may want to experiment with the amount of light before you commit important work to your process. If you want to play with reexposure bathes with chemistry, you can start with (there was a url link here which no longer exists).

Their chelating agent (Nitrilo-N,N,N-trimethylene 3.0 g phosphonic acid pentasodium salt) is difficult to obtain at reasonable prices, but you can substitute it with just about any chelating agent that comes handy: EDTA, DTPA, even Citric Acid worked for me. If you don't store the reexposure bath for prolonged times, you can also leave out the p-Aminophenol. The Acetic Acid in that formula serves as buffer at pH 6.0, so you can't replace it with Citric Acid. If you use Sodium Carbonate instead of Sodium Hydroxide, expect a precipitate from Stannous Carbonate at first, but this should clear up as you add chelating agent.

 

[frobozz]

There are movie film processing places that claim they can just process RVNP film in E6 and it comes out OK. I had some done that way (few hundred feet of 16mm) and it wasn't a rigorous test and I didn't shoot color cards or anything, but the results were totally passable. I wouldn't do it for still work if you care about perfect color, but if you don't, or if you plan to scan the slides and fix the colors that way, it might work OK.

Duncan

 

[R Paul]

Thanks for the replies.
Rudeofus, would you have an amount of citric acid in your formula? I would use the solutions as one shot. A thought would be to use standard E6 reversal bath. I have done light reversal with 120 b&w and it is a pain, but it does work The developers would be the sticking point, because the color dev uses benzyl acohol, but it looks doable. The bleach is standard ferricyanide bleach so that's ok--- I couldn't get the activator for persulfate bleach.
Frobozz, it may be worth trying E6 for test shots,but the different formulation for the color dev may cause changes later on . Anything decent I would scan,but to have some shots fade away really stinks-- and its always the best ones too

You know I'm just gonna bite the bullet ,and get a roll. 400asa slide film isn't exactly common .
Rob

 

[Rudeofus]

One recipe for 500ml reexposure bath worked for me and went as follows:

[TABLE="class: grid, width: 300"]
300 mlwater
0.5 gSnCl2 * 2 H2O
16 mlNaOH 25% solution
75mlAcetic Acid 10% solution
1.5 gEDTA
water----> 500ml
[/TABLE]
This recipe is in no way optimized or fine tuned, but it worked well for me.

 

[R Paul]

One recipe for 500ml reexposure bath worked for me and went as follows:

[TABLE="class: grid, width: 300"]
300 mlwater
0.5 gSnCl2 * 2 H2O
16 mlNaOH 25% solution
75mlAcetic Acid 10% solution
1.5 gEDTA
water----> 500ml
[/TABLE]
This recipe is in no way optimized or fine tuned, but it worked well for me.

Thanks. Now why is there EDTA in the formula,and what kind is it (sodium or potassium salt,or pure EDTA base).
I want to get my head around why the ingredients are there,as opposed to cookbook style. Could I drop it if I used distilled water to mix it up?

When I get some examples run off, I'll post them back here
Rob

 

[Rudeofus]

Sn2+ is an ion which forms lots of insoluble salts, and if you leave it in solution for some time, it will precipitate out, distilled water or not. The EDTA is there to keep it in solution, I referred to this necessary chelating agent in one of my previous postings. I used the free acid because I had it sitting on my desk, but obviously you can use Na2- and Na4-EDTA if you adjust the amount of NaOH added to the mix accordingly.

 

[R Paul]

Now I know why EDTA has to be there.
Thanks again
Rob