Development times for pull processing of T-Max 400?

I want to pull process T-Max 400 2 stops using D-76 at 20 deg C. Can

anybody verify the time needed?

 

Somewhere I read that you should extend/shorten the time by 10-15% for

each stop of push/pull-processing. Also Kodak states that no extra

time is needed when push processing one stop but at two stops the time

given, 10 1/2 minute, is what you get when multiplying the standard

development time, 8 minutes, by 1.15^2 (ie 2 stops given extra 15%).

 

So, then two stops of pull processing should be ~ 6 minutes? (8 /

(1.15^2)) Or should it be ~ 5 3/4 minute? (8 * 0.85^2) Or perhaps

something entirely else?

 

According to my reasoning the first (6 minutes) should be correct

since "pushing it" 2 steps would bring it "back" to normal development

of 8 minutes. Am I thinking correctly?

 

The reason to this is that I am to bracket a whole film by two stops

(-2, 0, +2) while the camera is secure on a tripod. In the darkroom I

wish to cut the film into three pieces and load on different reels and

then in developing pulling it two stops, normal time and pushing it

two stops giving me all combinations of

underdeveloped/normal/overdeveloped and

underexposed/normal/overexposed. We have a darkroom at our school and

wish to show new members how these combinations look when explaining

development and exposure to them.

 

Do you think 2 stops is too much? I want the effect to be clearly

visible and think that one stop might be to subtle.

Why pull TMY 2 stops when you can shoot TMX at the rated speed of 100?<br><br>

"Do you think 2 stops is too much? I want the effect to be clearly visible and think that one stop might be to subtle."<br>

--> Too much for what? What are you trying to do?<br><br>

Regardless, you can find processing times here: <a href="http://www.digitaltruth.com">Digital Truth</a><br>

Though I don't think they show anything for a two stop pull of TMY. Again, if you want a 100 speed film, just shoot TMX.

Grant,

 

as I stated, I am not interested in a 100 speed film, I am interested in showing how a underexposed/overexposed vs. underdeveloped/overdeveloped film looks. You can see what I mean this page under "Exposure": http://unblinkingeye.com/Articles/Mortensen/mortensen.html

 

I could just print this picture on my laser but I think the result would be not half as good as the print I wish to make.

 

I have been searching the web for developing times and found nothing. Digital Truths Massive Development Charts only show D76 at the solution (1+3) at EI 200. I wish to have for EI 100 and preferably 1+0 or 1+1 (which are the recommended dilutions that we use in our lab).

 

Again, this is ONLY for instructional/educational purposes and not for general photographic use.

 

Anyone else?

As a rule of thumb I reduce development time by 1/3 per stop

downrating, e.g. if the time at 400 ASA were 9 mins then at 200

ASA it would be 6 mins. Typically I rate HP5 (nominal 400 ASA)

at 160 ASA, but I have downrated right down to 64 ASA (just to

prove a point to myself).

Max,

 

Maybe I don't understand exactly what you are trying to accomplish (even after looking at the link you listed). If you are trying to demonstrate the effects of over/under exposure and over/under development, why are you trying to pull the film. If you pull 2 stops and adjust the development time accordingly, your negs will come out looking like normal (minus pull processing shortcomings). Are you trying to show how the image quality (tonal range etc)is affected when pull processing or are you instead trying to show the effects of over/under development/exposure while pull processing? Regardless, I would call the Kodak Film customer service line in order to get your development times. I called there to get push times and the results were great.

 

Here is the info:

Professional Photography and Photoprocessing Chemicals:

- E-6

- B&W

- Kodak Professional Papers

 

Kodak Information Center

9 am - 7 pm

 

Mon-Fri 1-800-242-2424 ext. 19

 

I'd give them a ring.

Try shooting a roll of one scene at at ISO 100, cut it into short lengths, develop them for various times ranging from about 50% to 75% of normal development. Then you can tell us what time to use!

Timothy,<P>

 

I think that we just use different terminology, since you describe almost what I want to do. With <I>pull processing</I> I mean just to shorten the development time as opposed to <I>pulling the film</I> where I mean both setting the film speed to a slower value (overexposing) and the processing to compensate for this.<P>

 

The purpose, as I stated before, was to show new members of our photo club, examples how a negative looks in all combinations of under-/overexposure and under-/overdevelopment. For a newbie to the darkroom it might be difficult to see the difference between for example underdevelopment and underexposure. (As of now we have examples, hanging on the wall, of how the different contrast filters look when printing on variable contrast papers. It is very helpful when showing people how to print and what to expect.)<P>

 

The final result of what I wish to accomplish should be:<P>

 

<PRE>

<B>Negative 1A Negative 1B Negative 1C</B>

Underdeveloped Undedeveloped Underdeveloped

Underexposed Normally exposed Overexposed

 

<B>Negative 2A Negative 2B Negative 2C</B>

Normally developed Normally developed Normally developed

Underexposed Normally exposed Overexposed

 

<B>Negative 3A Negative 3B Negative 3C</B>

Overdeveloped Overdeveloped Overdeveloped

Underexposed Normally exposed Overexposed

</PRE>

 

The A negatives are shot using bracketing at -2 stops, B using plus/minus 0 and C using +2 stops with the film speed set to what the manufacturer recommends (400 in this case).<P>

 

So yes, as you point out, some of the negatives, namely those on the diagonal axis 3A-2B-1C will look "normal" although 3A and 1C will loose some in the process. The negatives 1A and 3C will probably look horrid, but that is just to prove the point. And the remaining will be somewhere inbetween these "extremes". (2B is of course the "correct" one.)<P>

 

I'll see if I can reach Kodak's Information Center on e-mail, calling from Sweden is too expensive for me :-)<P>

 

Otherwise, Al's suggestion of trying is a good one, but surely there has to be some data on this. I mean, more than one photographer must have set the speed wrong by mistake and had it corrected when developing. Although pulling a film obviously is not as common as pushing it I am surprised that this information is missing in the datasheets, especially since Kodak's sheet on T-Max is quite exhaustive. Or are the professional labs always using the 10-15% per stop rule when a customer come running to them and ask them to salvage their incorrectly exposed roll?<P>

 

Anyway, I'll be back with more info if I can find out anything more.<P>

 

Thanks everyone.

Today I recieved an answer from Kodak Technical Support:

 

<BLOCKQUOTE><I>For Kodak T-Max Professional Film, decrease your normal development time by 5% per stop. For Kodak Tri-X or Plus-X Films, you would need to reduce by 10% per stop. </I></BLOCKQUOTE>

 

I have not yet had the chance to try this out (too much to do before Christmas) but when I do I'll get back to you with the results.

And?

Well done! It worked perfectly. I had two rolls of TMY2 (TMAX400) one I'd exposed for 100 ISO but didn't know which SO, knowing TMAX is forgiving I could process both for one stop off, 5%, and they'd both be within tolerance. Thank you.