Pushing Tri-x to 1600 with Thornton's two part developer. How?

rpavich · Aug 26, 2016

Hi,
I am almost through with shooting a roll of Tri-X at 1600 that I had previously planned to dev in Diafine (Diafine calls out for EI of 1600 for Tri-X) and then I ran across Thornton's two part developer recipe and made some.
Here is the link:
(there was a url link here which no longer exists)

The recipe has directions for times in each bath for 3 ISO's
ISO 50 = 3min
ISO 100 = 4min
ISO 400 = 5min

What I'm wondering is; given what times are given, is it possible to push Tri-X 400 by adding time or do I stick with Diafine when shooting at 1600?

Dali · Aug 26, 2016

If your Diafine is already diluted, why not using it and stick with your plan?

Regardless how you expose it, your film is still ISO 400....

rpavich · Aug 26, 2016

Dali said:
If your Diafine is already diluted, why not using it and stick with your plan?

For fun?
Cause it's interesting?
Because I'm curious?

Fill in the blank.

Dali · Aug 26, 2016

Because it is too simple?

You know what? You test with whatever time and you keep us in the loop. As I said in another thread, I would be very interested in pushing Tri-X by 1 or 2 stops without loosing too much shadow or blowing the contrast.

rpavich · Aug 26, 2016

Dali said:
Because it is too simple?

So now that we've established that there might be a plethora of reasons to ask this question, do you have the answer or was that it?

Dali · Aug 26, 2016

The time you gave are obviously for ISO 50, 100 and 400 films. Your situation is pretty different as you under-expose your film by 2 stops.

Try with 8-10 minutes. What do you have to lose more than the film?

rpavich · Aug 26, 2016

Dali said:
The time you gave are obviously for ISO 50, 100 and 400 films. Your situation is pretty different as you under-expose your film by 2 stops.

Try with 8-10 minutes. What do you have to lose more than the film?

Nothing. I was planning on extrapolating to come up with a good guess like you did, but before I did I thought that it just might be a good idea to ask first just in case someone here on the APUG might have first hand knowledge of what worked for him/her that would trump my guessing...that's all.

Gerald C Koch · Aug 26, 2016

Diafine or another PQ based two bath developer would be the best choice for pushing. The phenidone will give you are real 2/3 stop increase in speed whereas a D-23 based two bath like BTTB will results in a 1/3 stop loss of speed. Just the nature of the two developing agents.

rpavich · Aug 26, 2016

Gerald C Koch said:
Diafine or another PQ based two bath developer would be the best choice for pushing. The phenidone will give you are real 2/3 stop increase in speed whereas a D-23 based two bath like BTTB will results in a 1/3 stop loss of speed. Just the nature of the two developing agents. BTTB is a poor choice as a speed increasing developer.

Thankyou Gerald, that's good information, for this roll, ill dunk in diafine.

Paul Howell · Aug 26, 2016

The problem with 2 bath developers is that you are limited to a range of development times as once the 1 bath is aborted and and bath 2 is added bath 1 is used up additional time in the 2nd bath will not increase density. Saying that I believe BT gave directions for using his 2 bath as a one bath when shooting zone for expansion and contraction. In that case rule of thumb is 25% per push, so Trix rated at 400 in BT 2 bath as 1 bath is 5 min, to 800 is 6:15 to 1600 another 25% would be 8 min. That is if you have tested your camera and BT 2 developer at recommend 400 and get an actual box speed of 400. Without testing you don't know if your personal ISO or EI is 200, 400 or 800. Not knowing how important the roll is you can sacrifice a frame in the middle and start at 8min and adjust up and down. If you are sure that your personal EI is 400 you can sacrifice a frame and process 1/2 in BT and the other half in Diafine.

With most developers when you push you are underexposing and overdeveloping with loss of shadow details. Diafine is a very low contrast developer and maintains shadow detail even at 1600 without an increase of grain but a loss of acutance which is why many don't like Diafine as it looks "soft". My best guess is when using BT you will be losing shadow details, maybe block the highlight and increasing gain size. I did experiment with Photographer's Formulary version of BT 2 bath and found too grainy for 35mm for my taste, but rather nice for 6X9.

rpavich · Aug 26, 2016

Paul Howell said:
The problem with 2 bath developers is that you are limited to a range of development times as once the 1 bath is aborted and and bath 2 is added bath 1 is used up additional time in the 2nd bath will not increase density. Saying that I believe BT gave directions for using his 2 bath as a one bath when shooting zone for expansion and contraction. In that case rule of thumb is 25% per push, so Trix rated at 400 in BT 2 bath as 1 bath is 5 min, to 800 is 6:15 to 1600 another 25% would be 8 min. That is if you have tested your camera and BT 2 developer at recommend 400 and get an actual box speed of 400. Without testing you don't know if your personal ISO or EI is 200, 400 or 800. Not knowing how important the roll is you can sacrifice a frame in the middle and start at 8min and adjust up and down. If you are sure that your personal EI is 400 you can sacrifice a frame and process 1/2 in BT and the other half in Diafine.

With most developers when you push you are underexposing and overdeveloping with loss of shadow details. Diafine is a very low contrast developer and maintains shadow detail even at 1600 without an increase of grain but a loss of acutance which is why many don't like Diafine as it looks "soft". My best guess is when using BT you will be losing shadow details, maybe block the highlight and increasing gain size. I did experiment with Photographer's Formulary version of BT 2 bath and found too grainy for 35mm for my taste, but rather nice for 6X9.

Im not sure, i havent tested with this developer. Ill soup this one in diafine, and the next on will be the test case.

Paul Howell · Aug 26, 2016

I found the data sheet from Photographers Formulary, I don't think you can use BT for push.

N -AND N + PROCESSING, TWO BATH

Fine photographers working with the Zone System who wish to control the contrast of their negatives during two bath processing to match their exposure for either low or high subject brightness ranges can do so. However, time is not a good control since the developing agents contained in Solution A which are saturated into the emulsion are virtually used to exhaustion during the immersion in Solution B. Therefore extension of time does not work well. Reducing times conversely leads to inconveniently short duration and the risk of unevenness. The best method is to vary the dilution while retaining the N time you have found to be right for your equipment. You should conduct new tests. For N - conduct trials at 1:24 dilution for both baths. For N + 1, start trials at 1:9 dilution for Solution A, and 1:14 Solution B. Note: do not use Solution B stronger than 1:14 or streaking, fogging, and negative unevenness is very likely.
ohce

Gerald C Koch · Aug 26, 2016

Since the BTTB bath A is alkaline, being a variant of D-23, some development will take place in it. To adjust film contrast the time in bath A need only be extended. This is not true of bath B. Therefor the temperature of bath A is important just as for a conventional developer. BTTB in contrast with its name is a divided developer and not a true two bath one as is Diafine. Extending the time in bath A of Diafine will have no effect nor will changing the temperature within reasonable levels.

removed account4 · Aug 26, 2016

rpavich said:
Hi,
I am almost through with shooting a roll of Tri-X at 1600 that I had previously planned to dev in Diafine (Diafine calls out for EI of 1600 for Tri-X) and then I ran across Thornton's two part developer recipe and made some.
Here is the link:
(there was a url link here which no longer exists)

The recipe has directions for times in each bath for 3 ISO's
ISO 50 = 3min
ISO 100 = 4min
ISO 400 = 5min

What I'm wondering is; given what times are given, is it possible to push Tri-X 400 by adding time or do I stick with Diafine when shooting at 1600?

sorry i can't help with the 2 bath you speak of
but with sumatranol C and dektol ( or ansco 130 )
i would do maybe about 6 minutes in the dektol ( or ansco139 ) 1:6
coffee and 6 or 7 minutes in the sumatranol

if it is rolls of film ... regular agitation in the dektol ( ansco130 )
1 fuill min, then 10 seconds at the top of the minute )
then constantly in the caffenol

if it is sheets, shuffle the whole time ...

my suggestion with thorton;s
is extrapolate, do 10 mins
as a test sheet ahd then then the real-deal
YMMV

rpavich · Aug 27, 2016

Update: i souped using diafine this time and now I'm shooting a roll of HP-5 at 400 to try BTTB Developer.
Once i establish that it works, I'll give pushing a try just for kicks.

Paul Howell · Aug 27, 2016

There have a few who post that they push with Diafine by giving the film a long wash after bath 2, the adding bath 1 and let for very long peroid of time to let as bath soak in then back in bath 2 for another long time. I don't recall the times, but stated that could push to 3200.

Gerald C Koch · Aug 27, 2016

Paul Howell said:
There have a few who post that they push with Diafine by giving the film a long wash after bath 2, the adding bath 1 and let for very long peroid of time to let as bath soak in then back in bath 2 for another long time. I don't recall the times, but stated that could push to 3200.

The whole purpose of using a developer like Diafine is for its convenience. Then there are those who are determined to take away this one advantage. No film was specified so I assume a 400 speed film. By using a phenidone based developer and taking advantage of the 1 stop latitude of the film to under-exposure it is easy to get to an EI of 1600 without pushing. So all this added time and effort gains you maybe one more stop. In addition there is nor authentication for this claim. Before anyone attempts it we really need more information.

Pushing Tri-x to 1600 with Thornton's two part developer. How?

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