Digital BW, The Print

Tri-X Users --

I'm old enough to remember when Kodak changed the speed of Tri-X. It had 
been rated at 200 prior to the change. Then in the mid 1950s they announced 
that its new speed would be 400. The film hadn't changed -- only its speed 
rating. The reason Kodak gave was the advent of wide-spread, accurate 
exposure meters, allowing them to lop off the exposure-safety latitude at 
the low end of the scale.

Years later I performed Zone System tests with Tri-X, various development 
times, prints made with both condenser and diffusion enlargers on 
Polycontrast paper (#2 filter), and patches both eyeballed and read with a 
reflection densitometer. My tests required tonal separation of swatches 
corresponding to zones 1-9. Here's what I found:

Tri-X printed with a diffusion enlarger:
Developed for 10 minutes @ 68° in D-76 diluted 1:1
Speed = 400
Provides one additional zone of separation, allowing a distinction between 
zones 9 and 10.

Tri-X printed with a condenser enlarger:
Developed for 7 minutes @ 68° in D-76 diluted 1:1
Speed = 250
Zones 9 and 10 cannot be distinguished.

Either method allowed a slight distinction to be seen between zones 0 and 1.

No telling how the new Tri-X corresponds to my old tests although my recent 
negatives (on the new film) have scanned well.

It's always worth giving film the least exposure that provides adequate 
shadow detail since additional exposure just builds grain and flattens 
highlights.

-- Victor Landweber