T-Max 400 has boomerang curve

[Photo Engineer]

The curves do not resemble those that we got in-house. These are quite heavily "sanitized". And, they do not really help Mark in his problem. You see, this might be a keeping problem on the shelf or during shipping, and EK does do keeping tests. Just pulling a sample does not help.

I have a composite curve I am posting here (Thanks to APUG member Terry Holisinger for the fine image). This superimposes a film, paper and print curve. The relative horizontal displacements are not correct.

The X axis is LogE and each number represents 0.15 log E. The Y axis is density.

This would have exposure data on it that would give us the absolute speed of the curve. This is related to the settings on the 1B sensitometer used for exposing the material.

Also, we use wider paper for film, as the density extends to 3.0 and as you see, it goes off the right side.

PE

 

[albada]

@Michael R: Assuming the slope is about .58, then I think the little horizontal ticks would be 0.2 log-E units each.

@PE: Sanitized? That didn't occur to me. There's no question that Michael and I both got upswept curves, but not severe enough to hurt folks much. Just a little more burning needed. Kodak didn't see that, and it makes me wonder what's going on. And the recent report of felt-trap dust outside and inside 35mm canisters makes me wonder some more. I'm glad I tuned the Mocon developer to work well with Ilford films, particularly Delta 400.

Mark

 

[Photo Engineer]

Sanitized does not mean that the curves were changed, but merely that information such as speed and exposure were removed. No developer or development time is evident, and there is no comment on keeping from EK. Bad keeping can do strange things.

PE

 

[Photo Engineer]

Yeah, the bump does appear to be there, but it is masked by the other data, but that shows the tolerance limits for the film though. If you could plot them on the same paper with the same axes you might see how yours compares.

Too bad you can't do that.

PE