Oddball cross processing schemes

[GeorgeSelinsky]

I wanted to run my own tests, simply to satisfy my technical curiosity, but at the moment I have no time to.

 

Just yesterday I had to ship a bunch of color negative film to the lab and one roll was mislabelled, so I decided to test it by snipping a few frames off the tail and developing it in a black and white developer (didn't bother with a stop or a fixer since I just needed to get a rough idea of what was in the frame). The rem-jet backing seemed to come off in the developer bath (I was agitating it like crazy because I needed speed over quality).

 

This got me thinking... what would happen if I put color negative film through a black and white negative process? What about a black and white reversal process?

 

My guess is that I'd get a black and white image with an orange coupler mask. I'm curious what the quality of that image would be.

 

I've also read somewhere on Kodak's still site that it's possible to take a piece of color negative film that was developed in a B&W negative bath and have the couplers release color into the image (I never was able to find that link again, even after searching).

 

I'm interested if John or anyone else could share their speculations on this.

 

Thanks,

 

- G.

[Rachel Oliver]

In relation to the last question isn't the K40 reversal stock a black and white with colour released later on in the process? I could be very wrong here but I think that's the case?

Olly

[Guest Chainsaw]

Rachel ~

You are thinking of Kodachrome reversal stocks (K-14 Processing). These are indeed based upon a B&W matrix and are not in any form a chromogenic film. The positive color picture information is added during processing by a series of dye baths and color re-exposure steps. It is an extremely complicated processing medium and there are only a few labs left that can do it. It is really a pity since it is one of the most beautiful and archivally stable forms of color photography. There are a multitude of discussions and links on this and Kodak's site concerning Kodachrome film so I won't go into technical detail upon the structure of the film itself or its processing since other more qualified persons have long since covered the same ground.

 

George ~

It sounds as if you are describing color redevelopment in B&W chemistry. If memory serves this is done after color stock has been processed normally and removed from the bath before it hits the Fix stage. It is then run through B&W chemistry to redevelop any unexposed silver, which in theory adds a surreal deep/glossy look to the blacks. I have never done this nor met any individual or lab that has either so I cannot give any probative insight unto its actual look. Besides the effect on the blacks I am not sure at all of the effect on the dye couplers.

 

Bump for John, Dave, Mitch...

[David Mullen ASC]

You're thinking of the ENR / ACE print process which involves b&w redevelopment. Don't know how they control the amount of silver retained in terms of why the later bleach step doesn't still reconvert all the developed silver back to silver halide. Unless they don't use a bleach step but use some form of b&w fixer to remove silver halides while leaving silver. Dominic would know.

[GeorgeSelinsky]

George ~

It sounds as if you are describing color redevelopment in B&W chemistry. If memory serves this is done after color stock has been processed normally and removed from the bath before it hits the Fix stage. It is then run through B&W chemistry to redevelop any unexposed silver, which in theory adds a surreal deep/glossy look to the blacks.

I never heard of what you describe, it is interesting I must say.

 

What I was referring to was processing a color negative in a black and white bath entirely, and then at a later point reemersing the film into a color developer to get the color couplers to release. I'm assuming the B&W hypo doesn't eat away the color couplers/dyes. You could also then theoretically bleach the silver out too.

 

- G.

[Dominic Case]

The rem-jet backing seemed to come off in the developer bath

Before saying anything else, this is a warning! Don't send motion picture colour neg through any other commercially operated process. In particular don't send it through a b/w neg process or a stills (C41) process (I've known people who do that by mislabelling the can to "make it simple for the lab"). When the remjet backing comes off in the developer it will stick to the following:

• the emulsion of your film (unremovable)
  
• the emulsion of everyone else's film in the same run (unforgivable)
  
• the rollers and pipes in the processing machine (unfortunate at best)
  

By all means try this stuff at home, or only with the cooperation of a crazy lab guy. Just - not here.

 

Next, don't send black and white stock through a colour process. You will have the entire silver image bleached to clear film, but most of the emulsion won't be on the clear film by then anyway - it will have fallen off in the hot developer. Go to look for it in all the places mentioned above. Don't tell them it was your film if you want to live.

[Dominic Case]

Don't know how they control the amount of silver retained

 

In the ENR types of process, three is a b/w redeveloper after the bleach. So the sequence is this:-

• colour developer - produces silver and colour dye image
  
• first fixer - dissolves away the undeveloped silver bromide from clear parts of image
  
• bleach - converts developed silver image back to silver bromide
  
• redeveloper - converts silver bromide back to silver (in proportion to dev time)
  
• fixer - removes any left-over silver bromide if the redeveloper was only partial
  

in other words the redeveloper simply reverses the effect of the bleach. The simpler but roughly equivalent "bleach bypass" process skips both stages, so the film goes from first fix to second fix.

In the normal colour pos process, the redeveloper doesn't exist (except separately, for sound, but that's a different story).

 

I've left out stops, washes, final rinses, sound application etc for simplicity.

[Dominic Case]

at a later point reemersing the film into a color developer to get the color couplers   

 

Don't know what's wrong with the html (sorry about the layout on previous postings, no idea what happened).

 

Anyway, that won't work as you describe it. The couplers are 'developed' as a byproduct of the original colour development. A better way of seeing it is that the exposed silver bromide grains react with a nearby bit of colour developer agent, to convert it to an oxidised from that will in turn react with the colourless couplers to form the colour dye.

 

If you've already developed the exposed silver bromide image, then it's too late, you can't develop it again.

 

Unless (thinks :huh: ) you bleached the developed and fixed b/w image then immediately went into a colour developer. Not really happy about any bleach carrying over into the developer, and I can't see any earthly reason why you would want to. But someone will! Just not here please :blink:

[John Pytlak RIP]

I'll second Dominic's warning about rem-jet: NEVER "sneak" a film with rem-jet backing into a process without proper rem-jet removal. It will ruin your film, and any other film going through that process. You will be "persona non grata" for many people. :angry:

 

Kodak color negative films use "colored couplers" that have a coloration that forms a "positive color correcting mask" as the couplers form dyes by reacting with oxidized color developer. So a B&W negative process would develop a silver image, and leave SOME of the colored couplers behind without reacting. As Dominic notes, it MIGHT be possible to bleach the processed film to convert the silver image back to silver halide, then redevelop it in a color developer to form a dye image --- NO guarantees of what the results would look like. :unsure:

[Luke Prendergast]

Regarding the rem-jet - it can be removed with sodium carbonate solution or denatured alcohol, correct? Any ideas on how long it might need in the bathtub? Will this only soften the rem-jet for stripping or will it dissolve it entirely?

[Dominic Case]

Sodium carbonate solution (or, officially recommended, borax) will SOFTEN the backing layer. Nothing will dissolve it, as it consists of a coating of very fine carbon particles.

 

A normal processing machine washes the softened backing off with spray jets of water, and finally with a rotating sponge or buffer. However, if any of the backing finds its way round to the emulsion side of the film, it will stick on, actually forming a chemical bond with the gelatin. So it can't be washed off!

[Phil Rhodes]

Hi,

 

Where do they get the gelatin from?

 

Cows?

 

Do vegetarian cinematographers have to feel guilty?

 

Phil

[John Pytlak RIP]

Photographic gelatin:

 

http://www.usask.ca/lists/alt-photo-proces.../may01/0398.htm

 

A by-product of the food industry, Photographic Grade Gelatin is much purer than gelatins used for food. Kodak founded EASTMAN Gelatin Corporation in 1930, but suppliers worldwide are now also used.

[GeorgeSelinsky]

but most of the emulsion won't be on the clear film by then anyway - it will have fallen off in the hot developer.

Modern B&W emulsions can survive pretty hot baths, I've seen processing specs go up to 90 degs F and even higher.

 

I never intended to suggest that the rem-jet backing will naturally come off in a developer solution, I'm sure it was in the bath but I just did it on a one shot basis (I used HC-110 stock concentrate that was mixed in 1998! Still got some image).

 

Anyway, it's just an interesting theoretical question. Maybe I'll play with it later.

 

I was wondering if there was a way to get rid of the orange coupler mask by using some chemical additive, so this way you could cross process color negative into reversal without it. You could also increase the contrast in the first developer and then perhaps get a normal contrast color positive image from negative film. Interesting thought.

 

- G.

[Guest Chainsaw]

I was wondering if there was a way to get rid of the orange coupler mask by using some chemical additive, so this way you could cross process color negative into reversal without it.

 

If I'm not mistaken the discontinued Kodak 5620 640T Teleproduction stock is manufactured without said masking. I've never looked at the processed negs for this stock (even after shooting it) but I was told this by several theoretically reliable people.

 

I'll field this to John for confirmation.

 

If you are sincerely interested in some serious experimentation I do have some cans of this I've kept on ice for a year or so. I don't have much use for it and I'd be more than willing to send it your way IF you will shoot it and let me view the results. B)

 

The other more obvious way I can think of to obtain a neg without the masking is to obviously cross-process reversal stock in ECN-2 chemistry. I staunchly recommend using this process with the new E-6 based 5285 over any of the old VNF-1 or RVNP reversal stocks. Due to the lack of formaldehyde stabilizers in the ECN-2 bath any cross-processed VNF-1 or RVNP reversal stocks are archivally unstable and unpredictable. They experience rapid color fading and shifting. Of course if you can have an IP struck it isn't all that problematic.

 

Richardson details his experiences in dealing with such issues on U-Turn here:

 

 

Desert Noir

[Guest Chainsaw]

Okay, what gives? My previous post shouldn't look like it was translated from or into the Cyrillic alphabet or some such crap. Damn BBCode. A little help?

 

 

For the interested, this link is easier to cut-and-paste than the last:

 

 

http://www.theasc.com/magazine/oct97/uturn/index2.htm

[John Pytlak RIP]

Kodak formulates and tests films for the standardized processes they were designed for. When you process a film in a process it was not designed for, you are on your own. As mentioned, some reversal films still require stabilization during processing, and will exhibit fading of dyes when cross-processed in a process that does not have a stabilizer:

 

http://www.kodak.com/global/en/service/tib/tib5200.shtml

[Dominic Case]

Modern B&W emulsions can survive pretty hot baths, I've seen processing specs go up to 90 degs F and even higher.

Call that hot? ECN2 colour negative process developer is at 41.1C (that's 106F).

 

I was wondering if there was a way to get rid of the orange coupler mask

The orange is not a separate filter layer (George correctly refers to it a coupler mask), but the actual colour of the undeveloped dye couplers in each layer. It's designed to compensate for the unwanted colour cast of the developed dyes and so reproduce purer colours.

 

When you think about it, it's hard enough to find dyes that will change colour on contact with an oxidised colour developer solution - let alone ones that are exactly the right colour both before and after the reaction! So I guess it would be harder still to find a way of bleaching out the undeveloped coupler without affecting the developed coupler in the same emulsion layers.