Why not 2 bath developer only?

[Sidd]

What I have read and heard till now that 2 bath b&w negative developers have many advantages over conventional single bath ones. Like, they are temparature and film independent, very good for highligh control, usually maintain and sometimes increase film speed, keep for long time etc.

My question is, if 2 bath developers are so good, then why do we use conventional single bath developers at all?

 

[retina_restoration]

What I have read and heard till now that 2 bath b&w negative developers have many advantages over conventional single bath ones. Like, they are temparature and film independent, very good for highligh control, usually maintain and sometimes increase film speed, keep for long time etc.

My question is, if 2 bath developers are so good, then why do we use conventional single bath developers at all?

2 bath developers are NOT temperature independent. You can vary the temperature of the two baths somewhat, but if you work at 85F (or 60F) then you are most definitely going to change the results. Many two part (divided) developers use a Bath A that is a functional developer on its own. For example, Barry Thornton's version of Divided D-23 has a Bath A that is nearly identical to regular D-23 and it acts as a rather slow developer, without the use of Bath B. So if you are using a divided developer of this type and you deviate significantly from 68F, you're going to have an effect on the outcome.

I've found that 2 bath developers rarely deliver full emulsion speed. I prefer Thornton's version myself, but it always requires 1/2 to 1 full stop more exposure to get negatives I want. Karl Matthias's "2B-1" is better at enhancing film speed, sometimes giving an extra half stop of speed, depending on the film you choose.

Divided developers aren't more popular because they require making from scratch from chemicals that not everyone cares to acquire and keep in their darkroom (takes up space, tedious to weigh out and assemble). It also adds another step in the process, and many people barely have the patience for standard "develop/stop/fix" protocols, let alone adding another step.

 

[Andrew O'Neill]

Trickier to use the Zone System.

 

[Paul Howell]

Thorton provides directions use as both a single bath and divided. I just finished my last batches of Diafine, very old still in cans. It was ok, but limited how I developed a negative as I was limited to a single ISO for each roll or sheet of film. As noted by Andew O"Neill expansion and contraction is much more limited. I found that Diafine held shadows very well, and provides a fine gained negative at the expense of edge sharpness. Most modern films can be shot at box speed or a bit above. the excpection is Tgain films which have very thin emulsions which cannot soake up much of the A solution, I had to shoot Tmax 3200 at 800. On the side of the coin, usable at any temp from 70 to 90, (at least Diafine) 3 mint A, then 3 mints B, water rinse, fix and done. In the 70s and 80s when a working PJ I carried a quart kit of Diafine, a packet of fixer, and small bottle of a wetting agent for emerancy use in the feild.

 

[John Wiegerink]

Divided developer are not bad at all and some folks would be better off using a 2-Bath developer instead of trying to play Ansel Adams the Zone master. I use Barry Thornton's 2-B, but have two different B baths. One bath B is with Sodium metaborate and the second is with sodium carbonate. You could use several bath B's for different results. You could use borax, sodium metaborate, sodium carbonate or even sodium or potassium hydroxide for different levels of PH in bath B. One nice thing about two bath developers is that they aren't real fussy on time and temp, which makes them very friendly for beginners.

 

[dcy]

What I have read and heard till now that 2 bath b&w negative developers have many advantages over conventional single bath ones. Like, they are temparature and film independent, very good for highligh control, usually maintain and sometimes increase film speed, keep for long time etc.

My question is, if 2 bath developers are so good, then why do we use conventional single bath developers at all?

I have tried Barry Thornton's Two Bath. My view is that "it's fine". I was neither dazzled nor disappointed. This is the first time I hear that a 2 bath increases film speed. I cannot see why that would be the case, and it's certainly not something I've noticed. I did a side by side comparison of various developers, and, if anything, the film I developed with BTTB seemed to either need more exposure or more development in order to match the negatives I got with D-23, D-76, and PC-TEA.

Divided developers aren't more popular because they require making from scratch from chemicals that not everyone cares to acquire and keep in their darkroom (takes up space, tedious to weigh out and assemble). It also adds another step in the process, and many people barely have the patience for standard "develop/stop/fix" protocols, let alone adding another step.

I suspect that this is the main reason. My impression is that most people buy developers commercially. I like to make film developer, but as a point of comparison, I stopped making paper developer for the time being and switched to commercial ones. I suspect that most film photographers enjoy playing with chemistry less than I do.