My XTOL/TMX test

[Matthew Cordery]

Well, I finally acquired enough 'stuff' to do my own development and testing. Would be interested in comments or feedback since this is the first test I've ever done.

Step 1: Exposure. Load Stouffer 21-step calibrated step wedge into loader with TMX. Using 150mm lens, focus at infinity. Meter a sheet of white paper and expose for Zone 10. Place camera close enough to paper so that white area fills frame. Make five exposures.

Step 2: Development.
a) Developer: Kodak XTOL, dilution of 1:2. Development times below
b) Stop bath: ascorbic acid. 30 seconds
c) Fix: Ilford Hypam, dilution of 1:4, 5 minutes
d) Clear: Kodak Hypo Clear, diluation of 1:4, 2 minutes
e) Wash: 8 minutes @ 30 second intervals using about 300ml water each time
f) Dunk in PhotoFlo.

Set temperature @ 23.9 C (75F), Rotation at 4.
Develop five sheets of film for 4 min, 5.5 min, 8 min, 11 min, 16 min, using 300 ml of developer. No chemicals were reused.

Step 3: Densitometry:
Place developed film in Enlarger. Use densitometer function built into RH Designs' Zonemaster II. Calibrate without negative in light path in order to determine absolute transmission densities.

Step 4: Analysis. Following the methodolgy outlined in Lambrecht and Woodhouses' very fine Way Beyond Monochrome. Referred to hereafter as WBM. Plot data using Matlab.

Dev Time Gradient Speed Point
--------- ------- ------------
4 0.2273 2.55
5.5 0.3465 1.40
8 0.4994 0.64
11 0.8465 0.50
16 1.2527 0.44

Speed point is the log relative exposure where the transmission density = 0.17.

Plot gradient as a function of exposure time and fit a curve to it. I tried using both a linear and a quadratic fit but the linear was fine.

Using the methods described in WBM, I can calculate the following values for development compression / expansion:

Zone Time (min' sec")
----- --------------
N-4 5' 47"
N-3 6' 12"
N-2 6' 40"
N-1 7' 21"
N 8' 09"
N+1 9' 18"
N+2 10' 48"
N+3 13' 06"
N+4 16' 54"

The N+4 value is beyond my development time range so a bit of an outlier but probably not too bad given the linearity of my fit.

Plotting the average gradient versus the speed point data, I note that my film speed is pretty close to TMX's 100 ISO rating. It's a bit slower, but not so much that I'm worrying about it.

I'm not going to make a sub-hobby out of film testing, but this was a fun and useful exercise and got me introduced to my new (used) toy.

[johnnydc]

Did you make sure the camera was focused at infinity

-or-

Correct for bellows extension?

[KenM]

Step 1: Exposure. Load Stouffer 21-step calibrated step wedge into loader with TMX. Using 150mm lens, focus at infinity. Meter a sheet of white paper and expose for Zone 10. Place camera close enough to paper so that white area fills frame. Make five exposures.

[photographs42]

I don’t like the look of TMX so I don’t use it. I do use Xtol with Tri-x or HP-5+.

Without making any real attempt to understand steps 3 and 4 of your process, I find it hard to believe that you can achieve N+4 and N-4. I’m not real sure about N+3 or N-3. That much expansion or contraction would normally require, at the very least, exposure compensation and in the case of N-3 or N-4, dilute developer and/or a water bath or other modified process.

The fact that you accomplished this with 5 sheets of film is amazing!
Jerome

[Matthew Cordery]

You're right in that it is pushing the envelope, so to speak, for the N+/-4 values. I figured I had the supplied methodology so I was going to play with it. It's the danger in giving a scientist an equation. Caveat emptor. ;-) I haven't really worked out any exposure compensation values yet.