TMax100 ; reciprocity characteristics : LUSENET : Large format photography : One Thread

Does anyone have a reliable guide as to the reciprocity corrections required for TMax100 for exposures > 1 second ; comments on both exposure compensation and development would be appreciated.

-- fw (, June 03, 2001


Hi FW,

The Kodak web site has the short table for reciprocity failure which I suspect is written on your box, but here is the link: shtml#1153016

There is no detailed curve like they have for Tri-X that I can find.


-- Scott Jones (, June 03, 2001.

Kodak's guideline is no correction needed up to 10 seconds. Steve Simmons has a chart for TMX in _Using the View Camera_ which is somewhat more conservative, but TMX has such a wide tonal range and long straight curve that less compensation is needed than for traditional films.

-- David Goldfarb (, June 03, 2001.

Indicated actual Is 1 2

-- Bob Moulton (, June 03, 2001.

1 s=1 2s=2.5 4s=6 8s=11 15s=25 30s=54 60s=1:55 1m=1:55 2m=4:00 4M=8:30 8M=17:30 15M=36:00 30M=1H30M 60M=3H30M

Hope this guide helps. Bob

-- Bob Moulton (, June 03, 2001.


I'm very interested in your adjusted figures. They don't correspond at all to the Kodak supplied data & I'm wondering what kind of testing underlies these numbers.


-- ernie gec (, June 04, 2001.

Bobs numbers are on the money as they are nearly identical to my set compiled from Howard Bond (Jan/Feb 2001 Photo Techinques pg 54) and Bruce Barnbaum ("The Art Of Photography" Second Edition pg 80). Barnbaum feels that a N + 1/2 is the necessary adjustment. Considering the age old axiom that the answer can only be as accurate as the least accurate input, my objective is to get in the ballpark. Should entensive reciprocity be something that you encounter regularly in your photography, there is always the densitometer.....

The limited amount of correcting I have done for reciprocity using the factor table listed by Bob with these factors seems to be fine. Out of habit, I take anything Kodak says about these factors and the darkroom with a grain of salt.

-- Michael Kadillak (, June 04, 2001.

Bob - those factors are very helpful - what development adjustments do you make, if any? Regards

-- fw (, June 04, 2001.


Is that N+1 or N+2? Or do you mean N + 5% (which would = N+1/2)


Robb Reed

-- Robb Reed (, June 04, 2001.

The reference to Barnbaums N + 1/2 associated with his reciprocity correction deserves further clarification. In essence, he is stating that because of the extended exposure, the net effect on the negative is an N + 1/2 with normal development. If you desire a N development, then you must give the negative a N - 1/2 to compensate for the contrast increased during the long exposure. Hope this helps.

-- Michael Kadillak (, June 04, 2001.

Michael ; I think that you have partly answered my question. In other words, at a normal EI (for N), and with normal development, if the exposure is greater than 1s, I should end up with N + 1/2 contrast in the negative. Knowing this, it should then be possible to place shadows and highlights and determine what development is required - despite the inherent increased contrast, I suppose it is conceivable in a dimly lit and low contrast situation that you would choose to extend rather than reduce development - in fact, I can imagine this type of situation quite easily. Is my thinking right?

Now, does the degree of contrast change as exposure increases - i.e. once you get beyond a certain time, does normal development then deliver a N+1, or N+2 without adjustment? Together with Bob's table, such knowledge would be most useful.

-- fw (, June 05, 2001.

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