Cinestill DF96 monobath

[Huss]

Noblex 135Sport, Ilford HP5+, Cinestill DF96 Monobath

 

[janew]

Wait, what? You drink it but don't want to wash the film in it?

It's well water, from the nearby community centre. Drunk and enjoyed by a great many. Partially, I think, for its mineral content. But it's definitely not filtered and purified like town water

 

[Donald Qualls]

It's well water, from the nearby community centre. Drunk and enjoyed by a great many. Partially, I think, for its mineral content. But it's definitely not filtered and purified like town water

What I've found is that I can wash in any old water at all -- as long as the final PhotoFlo (equivalent) rinse is mixed with distilled or deionized water.

 

[janew]

What I've found is that I can wash in any old water at all -- as long as the final PhotoFlo (equivalent) rinse is mixed with distilled or deionized water.

That's where I'm at! Or to be more precise, that's what I've begun doing.

 

[MattKing]

What I've found is that I can wash in any old water at all -- as long as the final PhotoFlo (equivalent) rinse is mixed with distilled or deionized water.

Not applicable to this particular use, but I think I would limit this advice to normal black and white film - colour slides or negatives might be a bit less tolerant.

 

[Donald Qualls]

@MattKing This is a thread about Cinestill Df96 monobath -- a strictly B&W chemical. Why would anyone with any sense try to generalize anything said here to include dye-image films? But beyond that, what makes you think C-41 and E-6 commercial processes weren't tested against a pretty broad range of potable water supplies? After all, having to constantly replace filter cartridges cuts into the profit margin of a mini-lab.

 

[laingsoft]

@MattKing This is a thread about Cinestill Df96 monobath -- a strictly B&W chemical. Why would anyone with any sense try to generalize anything said here to include dye-image films? But beyond that, what makes you think C-41 and E-6 commercial processes weren't tested against a pretty broad range of potable water supplies? After all, having to constantly replace filter cartridges cuts into the profit margin of a mini-lab.

Extending that, If you were really interested in getting repeatable, consistent results, you wouldn't be using a monobath

 

[Raghu Kuvempunagar]

Extending that, If you were really interested in getting repeatable, consistent results, you wouldn't be using a monobath

A single use monobath tuned for a specific film can give repeatable and consistent results. No?

 

[laingsoft]

A single use monobath tuned for a specific film can give repeatable and consistent results. No?

If you one shot it and control the temperature and agitation exactly then yeah. When I started doing b&w development I was very keen on monobaths, but that cooled off once I saw the repeated, repeatable results that I was getting from one shot rodinal or one shot d76. I just haven't managed to get the same consistency from df96.

One shotting DF96 would get expensive, I'd think though.

 

[MattKing]

@MattKing This is a thread about Cinestill Df96 monobath -- a strictly B&W chemical. Why would anyone with any sense try to generalize anything said here to include dye-image films? But beyond that, what makes you think C-41 and E-6 commercial processes weren't tested against a pretty broad range of potable water supplies? After all, having to constantly replace filter cartridges cuts into the profit margin of a mini-lab.

Donald,
Thus the qualification to my remark - which was also in response to your using "any old water at all", not "any old potable water at all".
I think you will find that the commercial C-41 and E-6 processes do have strong recommendations/warnings attached to them about water quality.

 

[Raghu Kuvempunagar]

One shotting DF96 would get expensive, I'd think though.

Economy and convenience offered by DF96 can't be matched by a single use monobath. But @Donald Qualls has had some success in formulating a single use monobath using HC-110, rapid fixer and ammonia. It does take substantially more developer than usual, but not too much. It should be possible to tune Donalds' monobath, if one is keen, to specific films to get consistently good results.

 

[laingsoft]

Economy and convenience offered by DF96 can't be matched by a single use monobath.

I dunno about that. I've noticed DF96 results getting bad after only 2 or 3 rolls. In addition to that, development times start to get long, plus it's an 30C process rather than a room temp process, I find that less appealing than measuring out some rodinal and throwing it in some water and stirring.

Don't get me wrong, I like Df96, It's just not my go to anymore.

 

[foc]

Donald,
Thus the qualification to my remark - which was also in response to your using "any old water at all", not "any old potable water at all".
I think you will find that the commercial C-41 and E-6 processes do have strong recommendations/warnings attached to them about water quality.

Fuji used to suggest the use of filtered deionised water for C41 wash and RA4 wash.
Some minilabs (trying to skimp) had problems because they used just tap water. They had chemical mix problem and wash tank growth of algae, clogging filters and causing circulation problems.
They sold units like this. They had a long life filter in them.

 

[Donald Qualls]

Kodak chemicals (at least the final rinse) contain anti-biological agents that generally prevent that kind of problem in that stage -- but they won't help in the wash stage before.

Few of us keep a wash tank running continuously for any length of time, so this shouldn't be a problem for most.

 

[Huss]

Leica M-A, Orion 15 28mm f6, Ilford HP5+, Cinestill DF96 Monobath

 

[Steve@f8]

Without a too detailed chemistry explanation, how does mono bath work? Normally we think of developers and fixers to be mutually exclusive, and normally we buffer the two either with the use of a stop bath, or at least a wash phase in between.
Well thought out I’m sure, and what’s more it works.

 

[Donald Qualls]

Without a too detailed chemistry explanation, how does mono bath work?

Short version: a monobath is developer and fixer mixed together. Both processes proceed at the same time, so the rate of fixing limits the amount of development. Obviously, the solution has to be alkaline (most developing agents won't work in an acidic solution), but fortunately, fixers generally don't care (they've traditionally been acidic because they used to mix gelatin hardeners into them, which require an acidic solution).

 

[Steve@f8]

Short version: a monobath is developer and fixer mixed together. Both processes proceed at the same time, so the rate of fixing limits the amount of development. Obviously, the solution has to be alkaline (most developing agents won't work in an acidic solution), but fortunately, fixers generally don't care (they've traditionally been acidic because they used to mix gelatin hardeners into them, which require an acidic solution).

Thank you for explaining.
I didn’t know what to expect, but that sounds the most plausible option, unless there’s some ‘clever’ chemistry where a reaction takes place at the end of development that somehow ‘switches on’ fixing. Or two different rate dependent compounds, but then how would you separate the rates other than by introducing a third chemical or compound when you want the fixer to kick in.

 

[Donald Qualls]

unless there’s some ‘clever’ chemistry where a reaction takes place at the end of development that somehow ‘switches on’ fixing.

If that were the case, I couldn't have made a monobath from HC-110, Ilford Rapid Fixer, and household ammonia (to bring the pH up -- borax or washing soda likely would have worked, but I had ammonia handy). No trick chemistry, just a matter of balancing the rates of the two processes. With Df96 you increase temperature to speed up development, and increase agitation to speed up fixing -- hence why pushing requires developing warmer and reducing agitation; you're using both "knobs" to get more development done before the fixer takes away the halide.

 

[Steve@f8]

If that were the case, I couldn't have made a monobath from HC-110, Ilford Rapid Fixer, and household ammonia (to bring the pH up -- borax or washing soda likely would have worked, but I had ammonia handy). No trick chemistry, just a matter of balancing the rates of the two processes. With Df96 you increase temperature to speed up development, and increase agitation to speed up fixing -- hence why pushing requires developing warmer and reducing agitation; you're using both "knobs" to get more development done before the fixer takes away the halide.

Thanks Donald. The more I learn about this the more I want to know about the chemistry. Some reading is necessary and will ultimately help me get the best out of my ‘wet‘ photography.

 

[Donald Qualls]

Point is, the chemistry is the same as if development and fixing were done separately -- but there's what programmers call a "race condition" between development and fixing when you combine them. Tuning a new monobath is akin to "fixing the race" to get the horses coming in the right order.

 

[Steve@f8]

Thanks again Donald.
PS Are you a chemist?

 

[MattKing]

Thanks again Donald.
PS Are you a chemist?

All appearances indicate that it is Donald's earlier work that Cinestill based their monobath on.

 

[Donald Qualls]

No, I'm not a chemist. I've fixed power tools for a living for most of the last twenty years; before that, I answered phones for a dozen, worked as a courier, etc.

As far as I know, Cinestill didn't base their Df96 directly on my HC-110 monobath -- but New55 quite openly did base theirs (now sold by Famous Format) on mine -- right down to the ammonia smell. If you buy the dry version of Df96 you'll get the fixer in the form of obvious sodium thiosulfate pentahydrate crystals.

 

[Steve@f8]

Impressive!