4X5 KODAK TXP 320, DEVELOPED IN HC-110.

I see many posts asking for developing times for TRI-X and here is my

latest data.

EQUIPMENT.

By the time I used up all of my OLD TRI-X, I had been able to buy on

E-bay a good densitometer for BW film and the modified Pentax digital

spotmeter. I had the Stouffer calibrated step wedge for printing and

checked the densitometer against the step wedge for accuracy. I

develop sheet film according to the method outlined in Ansel Adams

photo series, revised edition with Robert Baker. I split the

developer between two Paterson 5X7 trays and move the negatives back

and forth from one tray to the other. The set of negatives will move

from one tray to the other every 30 seconds. The length of time

between movement of each negative depends upon the number of

negatives being developed. With 6 negatives one is moved every 5

seconds, with 3 negatives one is moved every 10 seconds. For TXP 320

I decided to standardize on Dilution H, the unofficial dilution,

which is 1+63 from concentrate: 25 ml of concentrate + 1575 ml of

water = my usual working volume with 800 ml in each tray.

TESTING.

For film speed testing I used 9 minutes as the developing time since

that seemed to be the normal developing time for Dilution H with OLD

TRI-X. I exposed a negative for Zone I at each ISO starting at ISO

320 and moving down the scale to ISO 125, 5 negatives. I developed

all 5 negatives, plus an unexposed negative for film base + fog, all

together and my Zone I negative density of 0.10 was achieved at ISO

250. I then exposed two negatives for Zone V and Zone VIII and

developed them for 9 minutes. The corresponding Zone V exposed

negative had a density of 0.75, and the Zone VIII exposed negative

had a density of 1.30. I use a diffusion enlarger therefore, ISO 250

is my film speed and 9 minutes with HC-110 at Dilution H is my normal

developing time. For expansion I exposed two negatives, one at Zone

IV and one at Zone VII and developed them for 13 minutes. The Zone

IV exposed negative had the dark slide only 3/4 removed, I had FB+

fog and Zone IV on a single negative. The negative densities were

greater than 0.70 and 1.30. I repeated the exposures and developed

for 12 minutes. The resulting densities were within the ranges

suggested in Ansel Adams film testing procedures for N+1 expansion.

For contraction, I exposed two negatives, one at Zone VI and the

other at Zone IX. Again, I did not completely remove the dark slide

for the Zone VI exposure. I developed the set for 6 minutes and the

resulting densities were too low for one Zone contraction. I

repeated the exposures and developed for 7 minutes. The Zone VI

exposed negative was compacted one Zone, but the Zone IX exposed

negative was slightly above the recommended range for one Zone

contraction. I have decided to use 7 minutes for N-1 contraction for

better development of the low values, and I control the high values

with the choice of filters on variable contrast printing paper.

Normal development, 9 minutes: N+1 development, 12 minutes: N-1

development, 7 minutes at standard processing 68 F/20 C.

NOTE: I pre-soak my negatives for a minimum of 2 minutes and set my

timer ahead 20 seconds from the above times. I shuffle the negatives

in the developer for 20 seconds then start the agitation cycle

described above.

Questions and comments are welcome.

Paul