Help Understanding Diafine

[dazedgonebye]

In an earlier thread, diafine was recommended as a developer for push processing Tri-x.
I like what I read about it. Particularly the insensitivity to time and temperature.

Can someone please explain a few things to me?

If I shoot tri-x and process in diafine, is there any way to rate the film at 400iso, or is it only good for 1250-1600 iso?
Does it add a stop or 2 to every film processed?

Help.

 

[dreilly]

Usually, yeah, you get about two stops, but it does depend on the film. The diafine box has a list on it, but so does the massive development chart online, and google will give you lots of info, too.

The general rule of thumb is to shoot closer to the box speed in flat (lower contrast) lighting situations.

It's fun developer. I have a ton of really old tri-x in 120 that I have to shoot anywhere from box speed to 1200 depending on how old it is.

Seems like the biggest truth about diafine is that it depends on you...test your film at different isos and different conditions, and settle on your own rule of thumb.

Diafine, from the last two years of my experience, is at once very simple and very complex, with decisions about what speed to shoot at, and how to agitate, making subtle (or not so subtle) differences.

 

[bmattock]

In an earlier thread, diafine was recommended as a developer for push processing Tri-x.
I like what I read about it. Particularly the insensitivity to time and temperature.

Can someone please explain a few things to me?

If I shoot tri-x and process in diafine, is there any way to rate the film at 400iso, or is it only good for 1250-1600 iso?
Does it add a stop or 2 to every film processed?

Help.

Diafine is not really a push processor - no matter how often it is called that. This is what leads to confusion.

Push processing means more time or more temp equals more development - so you dev longer for underexposed negs - that's pushing. Some films and some developers are pretty tolerant of this kind of treatment.

But at the base of it all, push processing is nothing more than intentional under exposure and intentional over development.

Diafine is a compensating developer. It develops to exhaustion. All two-part developers - to the best of my knowledge - are this way.

The first part of the developer absorbs into the negative's gelatin. It is like a sponge - it can only absorb so much.

Then the first developer is removed (except for what is stuck in the gelatin of the film) and the second part of the developer is added - this 'activates' the first part in the film's gelatin. It will combine with the first part and process the exposed silver halide in the film until there is no more of the first part of the developer present - thus 'to exhaustion'.

You can stop the development early - by removing the second developer before it has acted on all the first developer that is stuck in the gelatin. But with a scant three minutes from start to finish for each part - you'd have to move pretty quickly, and I believe stopping would be mostly by guesswork and could result in some very uneven development.

No, Diafine is not a push processing developer. There is no reliable, effective way to get anything other than the rated speed of the film in Diafine from it (that is, 1000 ~ 1200 for Tri-X, etc).

Compensating developers also have another nice feature - they stop developing in some parts of the negative before others - since there is no more part A to work on in some parts sooner than others. The end result is that highlights tend not to be blown out as often, even when there are lots of darks present. Film takes on a tad more latitude in Diafine, and it is ideal for lowering contrast in a high-contrast scene - which is very likely what you have when you shoot available light at EI 1000 or so with Tri-X.

My recommendation would be to use Diafine as what it is - but don't think of it as a push processing developer - even though it may seem like one and people call it that - because it isn't one. If you want to push and be able to adjust your times / temps to allow for fine-grained control of the effective film speed, you need a more traditional one-part developer.

 

[dazedgonebye]

Thanks for the insights guys.
I read a bit on Barry's 2 bath developer before I started using it, so I think I'm getting the concept of a compensating developer down.
Now I have to wonder why Diafine works so differently than Barry's...which seems to work at about the rated film speed...even with very little difference in developing time.
I think I processed 50 iso at 3 minutes per bath and 400 iso at 5 minutes with very good results from the Barry's.
Is the Diafine just more "active?" (Don't know a good term for that.)

 

[bmattock]

Thanks for the insights guys.
I read a bit on Barry's 2 bath developer before I started using it, so I think I'm getting the concept of a compensating developer down.
Now I have to wonder why Diafine works so differently than Barry's...which seems to work at about the rated film speed...even with very little difference in developing time.
I think I processed 50 iso at 3 minutes per bath and 400 iso at 5 minutes with very good results from the Barry's.
Is the Diafine just more "active?" (Don't know a good term for that.)

I am not a chemist, so I could be WAY off. But I believe it has to do with the combination of ingredients that create something called superadditivity - when the various restrainers, developers, and accelerants are combined and how.

There are other two-part developers out there - Cachet AB55 is another example (part A, part B, 5 minutes plus 5 minutes, ta-dah) and it does not give an apparent increase in speed at all - you can supposedly develop a roll of ISO 50 and a roll of ISO 400 in the same tank and get the same results.

Frankly, I think such claims are almost always a bit on the inflated side - on the 'no such thing as a free lunch' theory. Like everything else in photography, developing is a series of compromises. Accutance versus graininess, EI speed versus everything.

I have no urge to try Barry's - probably because it became the 'it' developer recently, and that always puts me off a bit. Even if the stuff is great, if everyone is touting it, I head the other way. Probably stupid of me, come to think about it.

 

[dazedgonebye]

I don't know enough to take a stand for or against any developers. I asked around about idiot-proof developers (as close to as possible) and Barry's was suggested. Tap water out here is pretty warm all the time (about 26c at the moment) and about to get warmer. Getting and keeping developer to a lower and consistant temperature seemed like a very likely place for me to fail. So the Barry's was attractive. The fact that it is cheap and keeps for a long time looked good too.
No doubt, someone more skilled could get better results with a process fine tuned to my film and shooting conditions, but unfortunately, I can't find that guy or get him to do my film for me.

I'm going to order some Diafine and shoot some tri-x at 1250 iso and see what happens.

Thanks for the input.

 

[bmattock]

Well, I suspect you'll like Diafine, it is very nice. But if you want to shoot slower than EI 1000 or so, you might want to use something other than Tri-X. Other B&W films don't get the speed boost that Diafine gives Tri-X.

 

[dazedgonebye]

I'll stick to the Barry's for 400 and under. I've got results I like and I'm not inclined to experiment except to add new capabilities...like (not) pushing tri-x. 🙂

 

[Sam N]

Diafine was recommended to me in the thread you mentioned. So far I'm pretty happy with the results. I usually shoot at a lower ISO in more light, and 1600 for Tri-X is a bit optimistic. I think 1200 does work better.

Speaking of Diafine, has anyone tried it with DELTA 3200? I shot a roll of this and I'm wondering if I should put it in Diafine with the Tri-X or just send it to the local lab.