Tri-X 400 + Rodinal

applesanity said:

I'll try that for the next roll. What is a good time at 20C for 35mm Tri-X at 400 for 1:50? The Massive Dev Chart says 13 minute. Or should I rate the film at a different speed....

Unfortunately, I'm totally unfamiliar with that graph to which you all keep referring.

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Thornton's book "The Edge of Darkness" goes into this in further detail on this, but experience shows me that as long as I have given the film enough exposure in the toe portion of the curve, by rating Tri-X at 200, I can start by reducing the development time by 20% from a published manufacturer's rating as a starting point. When I look at the only real problem through the years it is not the type of developer I used, but the fact that most of the time, development time was just way too long, period. Rodinal is one of those that lowering development by 20% for conventional films, and 25% if it's Tmax films, makes a remarkable difference in the result.

ericdan said:

good summary, but doesn't agitation affect the highlights, too? Just by agitating more you can get denser highlights I think.

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Every change has an effect for sure. When agitation is increased, as you note, the highlights will increase in contrast the most, and down the midtones it will increase less, and shadows are basically not affected at all. With extended agitation intervals the opposite happens to the highlights, they get compensated; midtones remain much the same, and shadows get a bump due to the extended time.