View Full Version : Need help finding correct stock & working dilutions for Kodak T-Max RS

Bob Coon
12-Sep-2009, 23:05
I am new to developing 4X5 film (having sent out for lab development in the past to just get underway using a 4X5) Now I am turning my attention to development at home. And am a bit confused.

Using Kodak T-Max 400 film
Developing in T-Max RS
Develop 5 minutes at 75F

Kodak's literature is all about time and temps and a bit lacking on the mixing of stock and working solutions from the A and B chemistry.

My question: What is the correct mix for Stock and the correct mix of that Stock for a Working solution? I seem to have found 3 different options and need some help putting together the details.

so... do I

Mix A+B together for stock (no water).
For usage, dilute 1:9 with H20 for working solution.
Making about 10 quarts total.
e.g. - Dump the little bottle into the big Kodak bottle - add 100 ml from that Kodak bottle and add water to = 1 liter for usage.


Mix A+B together add H20 to make 1 gallon of stock.
For usage dilute 1:9 with H20 for working solution.
Making 10 gallons total.
e.g. - Dump the little bottle and big bottle together add water to one gallon - then take 100 ml from that gallon add water to = 1 liter for usage.


Mix the A+B together add H20 to make 1 gallon, then divide that into two 1/2 gallon containers.
For usage, use one 1/2 gallon for development returning used developer back to bottle replenishment style.
Add in from 2nd bottle at a rate of 1.5 ounces per (one 8x10 sheet or the equivalent of four 4x5 sheets, or one roll of 135-36) processed. (meaning the 1/2 gallon grows in volume eventually reaching a full gallon right?)
When the second half gallon is used up the developer is exhausted and ready to be replaced.


Each of these scenarios have very different dilution outcomes. Which is it? Can anyone shed some light (pardon the pun) on the subject?
Thanks in advance.

12-Sep-2009, 23:44
Your first example is the best method.

I used to do it a bit different via a method sent to me by Kirk Gittings, but which still kept the A+B solutions separate, although mixed with water. I mixed Part A with enough distilled H20 to make 32 ounces, then mixed Part B with distilled H20 to make 32 ounces, and labelled the bottles.

When it came time to use them I used the ratio 1:1:6, which works out to 1:8.8, very close to the 1:9 recommendation, and it always worked perfectly for both sheet and roll film.

I'm not sure if longevity would be affected by mixing A+B from the outset, but the way I describe above it lasted for over a year without any noticeable degradation.

17-Sep-2009, 14:48
I broke all the rules [ and survived just fine thankyou]
I figured part B was separated out cuz it would spoil. I called Kodak to ask what was in B, but the nice phone folks could only address MSDS issues. Since I usually develop film sporadically, I didn't want to mix the stock A+B , use part of it, then have the rest spoil, so I went ahead and [highly] diluted part A [only] for oneshot use on TMY 120- that is, only enough for one tankful at a time- like i learned from Ansel and HC-110- only it's easier with RS account it's a lot runnier than HC-110 syrup. I did IIRC do a set of test rolls at EI 250 and 400 and decided that everything was fine, even at 400, so I never looked back. I haven't tried it thus with sheet film, nor with "TMY-2". So what IS part B anyway?

11-Oct-2009, 23:14
I've heard of some people just tossing the Part B...

12-Oct-2009, 12:06
I just mix part A & part B together & store that way in the original bottle.

At the time of development I mix 3 oz. out of the bottle with 21 oz. of water to make 24 oz. of working developer (1:7). Some people like 1:9.

N development (for me) is 7.5 minutes in a Jobo drum for T-Max 400, constant agitation, after a 5 minute water pre-soak all at 75 degrees.

Works for me.

Richard M. Coda
12-Oct-2009, 12:22
I mix the Part B in with the Part A.

Generally I use 1:9 @ 75 deg for TMax 100 for 7 minutes.

For TMax 400 I use 1:15 @ 75 deg for 8 minutes.

These are for Jobo in Expert tanks at 75 deg., rotation at 3.5

12-Oct-2009, 18:31
Or just use the non-RS.

15-Oct-2009, 13:59
Non-RS isn't recommended for sheet film, if I recall.

15-Oct-2009, 17:28
Non-RS isn't recommended for sheet film, if I recall.

I forgot the 'smiley' on my post, but the non-RS works fine for some (including me). But it is not recommended by big yellow.

jim kitchen
15-Oct-2009, 18:08
My historical notes for T-Max RS indicate the following times, and blends:

Development times are for 75 Degree F (24 degrees Celsius)

One time use development (T-Max rated at ISO 100)

Note: these could be very good starting times for TMY rated at ISO 400 too, but for the moment, I am not certain since I cannot find my notes regarding TMY.

Agitation is continuous from N+2 through to N-2

N+2 T-Max RS (1 : 4) 11.0 minutes

N+1 T-Max RS (1 : 9) 16.0 minutes

Normal T-Max RS (1 : 9) 11.5 minutes

N-1 T-Max RS (1 : 9) 8.5 minutes

N-2 T-Max RS (1 : 19) 14.0 minutes

Intermittent agitation (Compensating Development):

N-3 * T-Max RS (1 : 19) 15.0 minutes

N-4 * T-Max RS (1 : 19) 12.0 minutes

N-5 * T-Max RS (1 : 19) 9.5 minutes

* agitate for first 30 seconds for for each minute during first three minutes, then 15 seconds every two minutes.

N-2 development requires an an additional exposure of one (1) f-stop.

N-3, N-4, and N-5 require an additional exposure of two (2) f-stops.

I use XTOL with TMY, and I will post my development times in another post, once I finish a few more tests. Unfortunately, I have not used T-MAX RS for quite a long period of time.

jim k