How to compensate for XTOL dilution with increased developmentgreenspun.com : LUSENET : B&W Photo - Film & Processing : One Thread
After two years of black and white photography, all of it using D-76 and Tri-X 400, I've decided to jump to a finer grain film/developer combination. After much research, I settled on TMAX 400 and XTOL diluted 1:3 as the combination most suitable to my particular photographic needs. My first results with XTOL/TMAX 400 were similar to the complaints of many other posters on the boards: my negatives were underdeveloped.
Reading futher on this message board, I became aware that there was a minimum amount of XTOL needed for each roll of film. If you have less than the minimum amount of STOL present, and you need to either 1) increase the development time above that listed in the normal development charts or, 2) find a way to get more developer into the tank by using a lower dilution. Failure to take one of these actions, and you'll get underexposed negatives.
I therefore set out to determine exactly how much I should increase development times for my 1:3 XTOL dilution in my stainless steel, inversion-style development tanks.
Due to my inexperience (I never learned the principles of B&W development, just a recipie for D-76 / Tri-X development) and the confusing nature of Kodak's Development Notes for XTOL (they use, at various times, three different units of measurement: milliliters, fluid ounces, and rolls per liter), this took quite a bit longer than expected. I'm posting the results here to save other newbies time, and in the hope that someone else will double check my calculations!
HOW TO PROPERLY COMPENSATE FOR XTOL DILUTION IN A 16 OZ AND 32 OZ CAPACITY TANK (I think)
There are three factors that need to be considered when adjusting XTOL development times for the amount of developer present in the tank: the capacity of your development tank, the dilution ratio of your developer, and the number of rolls being developed.
I have two tanks:
a 18 oz tank that holds two rolls of film and 16 oz of developer when filled to capacity a 36 oz tank that holds four rolls of film and 32 oz of developer when filled to capacity
I've standardized on milliliters to perform the calculations; therefore my 16 oz capacity tank holds 473 ml of developer. My 32 oz capacity tank holds 947 ml of developer.
Next, we need to know how much stock developer (i.e. undiluted) we need for each roll of film to process properly, and when we need to increase development time. This can be obtained from Kodak's XTOL technical notes (I've converted from rolls/liter to ml/roll):
IF YOU HAVE: 1000 - 200 ml undiluted XTOL per roll, THEN: use normal development time
IF YOU HAVE: 199 - 100 ml undiluted XTOL per roll, THEN: increase the development time by 15%. This is the ADJUSTED DEVELOPMENT TIME.
IF YOU HAVE: 99 ml - 67 ml undiluted XTOL per roll, THEN: increase the ADJUSTED DEVELOPMENT TIME by another 15%.
All right. Still with me? Now we need to figure out how much developer is in each of my tanks at various dilutions. To do that, we simply divide the total tank capacity by the amount we've diluted the XTOL. The charts below contains the results:
AMOUNT OF XTOL IN 16OZ/473ML CAPACITY TANK AT VARIOUS XTOL DILUTIONS
DILUTION ML OF XTOL PRESENT IN THE TANK stock solution 473 ml 1:1 dilution 237 ml 1:2 dilution 158 ml 1:1 dilution 118 ml
AMOUNT OF XTOL IN 36OZ/947ML CAPACITY TANK AT VARIOUS XTOL DILUTIONS
DILUTION ML OF XTOL PRESENT IN THE TANK stock solution 947 ml 1:1 dilution 474 ml 1:2 dilution 316 ml 1:3 dilution 237 ml
Almost home. Now we simply need to divide the amount of XTOL in the tank by the number of rolls we're developing. This gives you the number of ml per roll. You can compare this with the Kodak development time recommendations (see above), and you'll know how much to increase your development time (if any). I've included the results below. Thanks for your patience, and I hope someone finds this useful!
XTOL DEVELOPMENT ADJUSTMENT TABLES
STOCK SOLUTION IN A 16 OZ / 473 ML CAPACITY TANK 1 roll = normal development time 2 rolls = normal development time
1:1 DILUTED SOLUTION IN A 16 OZ / 473 ML CAPACITY TANK 1 roll = normal development time 2 rolls = increase NORMAL time 15% (this is called the ADJUSTED TIME)
1:2 DILUTED SOLUTION IN A 16 OZ / 473 ML CAPACITY TANK 1 roll = increase NORMAL time 15% 2 rolls = increase previously ADJUSTED time another 15%
1:3 DILUTED SOLUTION IN A 16 OZ / 473 ML CAPACITY TANK 1 roll = increase NORMAL time 15% 2 rolls = exceeds max. # of rolls recommended for XTOL present
STOCK SOLUTION IN A 32 OZ / 947 ML CAPACITY TANK 1 roll = normal development time 2 roll = normal development time 3 roll = normal development time 4 roll = normal development time
1:1 DILUTED SOLUTION IN A 32 OZ / 947 ML CAPACITY TANK 1 roll = normal development time 2 roll = normal development time 3 roll = increase normal time 15% 4 roll = increase normal time 15%
1:2 DILUTED SOLUTION IN A 32 OZ / 947 ML CAPACITY TANK 1 roll = normal development time 2 roll = increase normal time 15% 3 roll = increase normal time 15% 4 roll = increase previously ADJUSTED time another 15%
1:3 DILUTED SOLUTION IN A 32 OZ / 947 ML CAPACITY TANK 1 roll = normal development time 2 roll = increase normal time 15% 3 roll = increase previously ADJUSTED time another 15% 4 roll = exceeds max. # of rolls recommended for XTOL present
-- Matthew Nolker (email@example.com), September 15, 2000
It appears that the message board software didn't preserve all of my carriage returns, messing up the formatting of the charts. I guess I should have done a test post somewhere first.
I apologize if the post is difficult to read. Let me know if it's too confusing and I'll post a better version.
-- Matthew Nolker (firstname.lastname@example.org), September 15, 2000.
Last time I checked, Kodak recommended a minimum of 100 ml of XTOL stock solution per roll. Keep in mind that a "roll" is a 36 exposure strip, not a 24. If you go by the recomendations of Anchell, he suggests more stock solution than Kodak (can't remember how much). I always use the stuff 1:3 and I find the easiest solution (no pun intended) is to always use a slightly bigger tank- i.e., a single roll in a double tank. I also rarely shoot 36 exposure rolls and that gives a substantial safety margin. If you're pushing the limits with 36 exposure rolls and want to do as many as possible in one tank, than you certainly have to think about this. OTOH, that situation probably isn't one where extreme dilutions would be used- i.e., commercial or semi pro jobs with faster processing in less dilute developers. Time=$$ :-)
-- Conrad Hoffman (email@example.com), September 15, 2000.
Typically the suggestion is to have not less than 125 ml of fresh stock pre 80 square inches of film (1 - 35mm x 36 or 1 - 120 or 4 - 4x5 or 1 - 8x10). I know this contradicts what the Xtol data sheet says, but the data sheet is also assuming that you using the entire 1 liter, or you are putting the used developer back into the container of fresh. AND typically capacities are understated to ensure that the developer works properly. If you have older developer, not stored well, the capacities stated are probably still OK, if fresh (just mixed) you have more capacity. Thus the difference in recommeded minimum amounts of stock.
I just checked the data sheet, and above the table of capacities (rolls per liter) the section on diluted developer does state minimum 100 ml per 80 square inches. The table IS for undiluted developer.
I have however, always maintained, that with extended development time you could go as low as about 70 ml per roll, which is what you figured out from the table. The only thing is what the time should be based on, Kodaks table of 200 ml per roll, their statement of 100 ml per roll, or the standard suggestion from users of 125 ml per roll.
Thanks for the work.
-- Terry Carraway (TCarraway@compuserve.com), September 16, 2000.
One of the things I left out from the original post was a conversation about the minumum XTOL needed with a guy in Kodak Professional technical support. According to him, the recomendation of at least 100 ml of undiluted XTOL per roll was primarily made because many people were re-using the developer, as you pointed out. Unofficially, if I always use fresh developer, they said they I should be OK down to 65 or 70 ml per roll (36 exposures, of course).
One other interesting comment the Kodak guy made: Apparently, they've been having so much confusion regarding the minimum amount of fixer being used, they're considering changing the published instructions to eliminate any mention of the 1:2 or 1:3 dilutions, including the proper development times.
I suggested less confusing instructions might accomplish the same goal.
-- Matthew Nolker (firstname.lastname@example.org), September 16, 2000.
From posts here and other boards, most people have found that you need a minimum of 125 ml of stock Xtol for the standard times. Even 100 ml is too little.
Now with extended times, I can see from their data that 70 ml should be fine.
The problem is, Kodak seems to contradict themselves in the data sheet. At one point the explicitly say that you need 100 ml of stock per roll, then they say that from 1-5 rolls per liter you develop for normal time, but for 6-10 you need to increase the time. Without further explaination, that seems to be contradictory.
They need to STATE that one is for one shot use and the other is for reuse/mixing.
But for me, unless I want to do some testing, I will use 125 ml of stock per roll at whatever dilution.
-- Terry Carraway (TCarraway@compuserve.com), September 17, 2000.
I use 125 ml of XTOL per roll as well. This means that you can develop two 36 exposure rolls only at 1:1 dilution in a 500ml tank. You can only develop one roll at 1:2 or 1:3.If I have more than 1 roll I use a 1000ml tank.
-- Robert Orofino (email@example.com), September 17, 2000.