Tri-X and Diafine
I know this topic is a well-trodden path, but I shot a test roll of Arista Premium 400 (aka Tri-X) in two different lighting conditions - one bright sunlight, and the other in a dull, late afternoon, cloudy, winter sky. The object was to ascertain what the speed was with the film developed in Diafine.
The test roll showed that, in bright sun, Tri-X/Diafine was very nice at an EI of 1600. There was no apparent loss of shadow detail.
In the low-contrast, dimmer light, an EI of 1600 caused a loss of shadow detail. An EI of 800 in the low-contrast, dim light gave excellent shadow detail.
In both instances, I was surprised at how fine the grain was!
The proof of the pudding is in the printing, so I marched off to DC (a 45 minute drive) and wandered Teddy Roosevelt Island and the West end of the mall taking identical photos at both 1600 and 800. In bright sun, the statue of Teddy Roosevelt, looked superb at an EI of 1600, both on the negative and in the print. In the fading evening light, I came upon the Korean War Memorial just as the last flicker of sunlight was touching the last statue in the line. I got off two quick shots. I did not post the 1600 shot. It had slightly less contrast - it just appeared a wee bit "muddy". The shot at an EI of 800 printed easily with just a little burn to bring out the flag in the upper left corner.
Both prints on Ilford MGIV - filter 2 1/2 - Dektol - and scanned using my old Canon LiDE 60
(Korean War memorial)
The Korean War Memorial print is about 7 x 10
The Roosevelt print is a 5 x 7
Camera was a Bessa L w/2.5 Color Skopar
Camera speed was probably 1/60th
MY CONCLUSION: Yeah, Tri-X in Diafine has a speed bump to 1600, but not when I need it. If pressed, I'd just leave my meter set at ASA 800 rather than try to toggle back and forth. The bright sunlight shot at an EI of 3200 also looked pretty good, but the shadow detail was disappearing.
I've been struggling with low-contrast prints for quite some time....and have tried numerous developers, films, etc. A few weeks ago, I thought to myself, "hmmmm, I wonder if my thermometer is accurate?". I got a new one from Freestyle and found my old dial-type thermometer to be almost 4 degrees off. Since I was usually developing around 68 degrees (so I thought), my negatives looked good, but were under-developed. Doh. Now I gotta buy a 3rd thermometer - can't have two disparate data points without resolving the conflict!
Odds are the third thermometer won't match either of the others.
Thanks for posting your results, by the way. It's interesting to see how the film and developer behave in these conditions. Diafine truly shows its usefulness in compensating for mixed lighting conditions on a single roll of film. Run a bracket from 800 to 1600 for any subject and you'll get a decent, printable negative.
I've had a lot of success with Tri-X and Diafine at 1600. It's one of my favorite combinations...but I haven't really experienced a loss of shadow detail, so that's a bit odd for me. I think I might shoot some at 800 and see what happens. Thanks for posting the info!
It's one of my favorite combos too. I can't see your prints, not being a member (need to pay up, I know) but I agree that the effective speed depends a bit on the lighting. I compromise and shoot at 1000-1250 most of the time, which pretty much works well regardless of the lighting.
EDIT: Oh yes, about the thermometer - man with one thermometer always knows what temperature his solutions are, man with two never sure. I'm in the same boat myself having used the same old steel dial thermometer last decade (well, in the 90s) with no problems, even for color, then recently getting a "better" glass one to calibrate it. The original was off. Or the glass one is. But it's easy to adjust the dial and not the glass so now they agree, at least at B&W temperatures. Seriously, for black and white it doesn't matter that much as long as you are consistent. They aren't going to be THAT far off. Calibrate your times using the same thermometer and you'll be fine. But change the thermometer calibration and your development times will have to change too.
If your dial thermometer is like mine and others I've seen, there's a nut behind the dial face. You can turn this to adjust the reading. I long ago lost the flat wrench that came with it for this purpose but long nosed pliers work fine. Just adjust it to agree with the other one and be happy, before you drive yourself crazy with a third!
Last edited by Roger Cole; 01-11-2012 at 10:19 PM. Click to view previous post history.
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Alas, the only nut behind the dial was me....
There is no apparent way to adjust this old Voss thermometer.
I did not take test shots at intermediate exposures between 800 and 1600, but I think your assessment ("1000 - 1250 most of the time...") is pretty good advice.