Mixing Film Stocks in the same developing tank (in particular Cinestill 800

[Brian M Harris]

The local lab I use in London for colour film processing (Rapid Eye) has said a big no to developing Cinestill 800t as they say it leaves lots of residue in there dip and dunk tanks and has/can affect the other films during the process.

I understand their concerns commercially as they are pushing through a lot of film on a run etc. I have phoned around a few others (Metro & Photofusion) and their response is the same.

Cinestill 800t is a great film, and I have a fair bit in the fridge and don’t want to stop using it.

I already develop/scan my own black & white film, so after a bit research and a Tetenal Colour Tec kit I developed my first roll of colour film and it came out great, I have a second roll waiting to be scanned which looks promising.

My question is can I mix film manufactures (and or film speeds) in the same developing tank i.e 1 x Roll Portra 400 and 1 x roll Cinestill 800t in the same dev tank ???

My thoughts are better to be safe than sorry and keep the Cinestill 800t separate from other film stocks.

Any thoughts on this would be appreciated.

Thanks

Brian

 

[MattKing]

I would be concerned about trace amounts of remaining remjet transferring from the Cinestill to the Portra. In addition, as Cinestill is actually ECN stock, use in C41 might affect the longevity and capacity of your C41 kit materials.
Otherwise though, you can mix any combination of C41 films and get good results.

 

[Photo Engineer]

MP films are supposed to use a different process. C41 uses a CD4 based developer, while MP films use a CD3 based developer. However, if you insist on processing them together, there is no severe chemical reason you cannot other than to having potentially degraded images due to the wrong developer - oh, and of course the rem-jet.

PE

 

[Brian M Harris]

I would be concerned about trace amounts of remaining remjet transferring from the Cinestill to the Portra. In addition, as Cinestill is actually ECN stock, use in C41 might affect the longevity and capacity of your C41 kit materials.
Otherwise though, you can mix any combination of C41 films and get good results.

Hi and thanks for confirming this, I developed a roll of Cinestill & a roll of Portra in separate tanks and separate chemicals as well.
If you average out the chemical costs per roll, it's not worth the risk

 

[Heathcliff]

I mixed Portra and Cinestill this weekend and fairly sure it affected the colour cast of the Portra roll . I won't be mixing Cinestill with daylight film again .

 

[Donald Qualls]

@Heathcliff Can you post photos of the negatives as well as scans or print photos so we can see what you're claiming? That's certainly not something we'd expect...

 

[YoIaMoNwater]

I'm confused. I thought Cinestill800T had the remjet layer removed so it can be processed without contaminating the developer. Obviously development in C41 will differ than ECN2 but I don't see how presence of the Cinestill800T can affect another film when they are both developed in the same tank.

Googling this seemed that this was an issue when Cinestill first came to the market (https://wkoopmans.ca/notebook/?p=18333). I've shot some rolls from that time (similar to the OP here from 2017-2018) and the negatives themselves do not have the same edge marking as now (i.e. before they had edge marking from motion picture films whereas the new packaging these days will say Cinestill800T). I've sent them to be processed at Boots (back before I started self developing C41 films) and didn't have any problems from them.

Unless @Heathcliff was developing an older batch where the remjet issue was still there then that's pretty worrying if this problem still persists.

 

[Donald Qualls]

AFAIK, Cinestill has always had the remjet "premoved" -- that was the primary selling point vs. buying a 400 foot roll of Vision3 and breaking it down enough to fit in a bulk loader (at much lower per-roll cost). Unless there's something else in the emulsion, I wouldn't expect anything except the minor color shift (in the Cinestill only) from processing an ECN-2 film in C-41 chemistry.

 

[Heathcliff]

here's a couple from the roll of Portra 400 shot at normal , both in daylight . Very washed out looking colour wise , if there's another explanation I'd be happy to hear it . I was surprised and after reading the original discussion here thought mixing Portra and Cinestill could be the reason . This was roll 5 and 6 processed in Bellini chemicals which has a capacity of 16 rolls , so shouldn't be exhausted yet .

 

[Donald Qualls]

If you exposed that as Portra 400, we found your problem -- that's 1 1/3 stop underexposed. Portra 160 in the edge markings...

 

[Heathcliff]

That's a typo error on my part , I shot the roll at 160 as I changed the fiddly iso dial on the GS645 to do so .

 

[Donald Qualls]

Those look pretty near normal to my (admittedly not very critical) eye. If you want more saturation, one way to get it with C-41 is to expose a little more -- 1/3 to 2/3 stop (so EI 125 or 100 on Portra 160) will produce more dyes in the image.

For the portrait, when shaded and lit mainly by sky, the color will always shift toward blue, and I do see that effect. The duck pond looks slightly cyan casted -- potentially due to developing problem (unrelated to having Cinestill in the same tank), or as likely due to a scanning error (wrong film profile?). For both, it looks to me as if you can correct the color, either in software after scanning or with filtration in a darkroom print.

 

[Heathcliff]

Yes back in the nineties when I shot neg as a newspaper photographer we used to push 2/3rds quite often to make the image more punchier . I’ve had a long break from processing colour neg but would like to do more but only if I can get decent results without a big investment . At present I’m
Using Patterson tanks and spirals and a Cinestill heater . I’m scanning with a 5d and an Essential Film Holder using Negative Lab Pro . Very happy with the software and compare favourably with Lab scans for a fraction of the cost .

 

[Heathcliff]

I was wondering if a depleted bleach or fix could also affect colour . Thanks for the advice anyway .

 

[foc]

If your bleach was getting exhausted you would get retailed silver in your negative and it would make the negative look dense. To confirm this, if you hold the negative by the edge, emulsion side facing you and tilt the neg back and forth you should see the image change from a negative to a dull positive.

The cyan look to the images ( I know you can colour correct) reminds me of underdeveloped negs. I think the edge markings should have more density.

 

[foc]

When I had my minilab, we processed a few films with remjet in our C41 processor. We would process the film as the last one of the day. That way if any particles came off the film they would be picked up by the circulation filter and we were ready for normal C41 processing the next day.
It never caused a problem.

 

[awty]

So could you just use a coffee filter after the Cinestill is processed?

 

[koraks]

So could you just use a coffee filter after the Cinestill is processed?

Cinestill has no remjet. So no need for coffee filters.

 

[Donald Qualls]

Cinestill has no remjet. So no need for coffee filters.

But to expand on this, I suppose you could filter your chemistry after processing Vision3 or other remjet backed film. Generally, if you do a sodium carbonate prewash with very vigorous agitation, then water rinse until the rinse runs clear, you won't have any remjet come off in the developer, so no need to filter it (though you'll still need to remove the last of the stuff with your fingers after wash and before Final Rinse).