Like others, I have been looking for a replacement for Barry Thornton's Exactol Lux. Pyrocat-HD is close but not the same. I shoot 35 mm Delta 100 and sometimes 400 so I was keen to develop the film speed development time combination and since I had a little Exactol Lux left I could make a comparison. The results are below. I hope they are helpful to others. If you have further questions, you may contact me at awulff@myexcel.com.

Pyrocat-HD 35mm Delta 100 & 400 Film Development Test

This test was run to determine EI and development time for Ilford’s Delta 35 mm 100 and 400 films in Pyrocat-HD. A print comparison was made against negatives of the same scene from the same roll of film developed in Kodak Xtol and Barry Thornton’s Exactol Lux. The purpose was to find a replacement for the no longer available Exactol Lux.

Test Procedure

A roll of each film, Delta 100 and 400, was exposed at sequences of varying ASA of a landscape scene with new houses and autos (sharp detail) and foreground foot bridge giving good shadow detail underneath. The camera was a Nikon with 55mm macro lens on tripod. The roll was then cut into small pieces and developed in a small Patterson tank. One piece in Xtol, one in Exactol Lux, and four in Pyrocat-HD 1:1:100 at 10, 12, 14, and 16 seconds to determine the film EI and development time. All developments were at 70 degrees F. The development of Pyrocat followed Barry Thornton’s technique of a two minute wash after hypo, pouring back in the used developer for two minutes with 30 sec. agitations, then the final wash. Agitations during development in all cases was 3 inversions left and right at start and then one inversion left and right each 30 seconds thereafter.

Film/print results

Delta 100 - Kodak Xtol 1:1, 70 F, 9 min. ASA 100, Print exposure 15 sec.
Delta 100 - Exactol Lux 1:1:100, 70 F, 10 min. ASA 100, Print exposure 9 sec.
Delta 100 – Pyrocat-HD 1:1:100, 70 F, 13 min. ASA 80, Print exposure 15 sec.

Delta 400 - Kodak Xtol 1:1, 70 F, 10 min. ASA 400, Print exposure 12 sec.
Delta 400 - Exactol Lux 1:1:100, 70 F, 12 min. ASA 400, Print exposure 12 sec.
Delta 400 – Pyrocat-HD 1:1:100, 70 F, 16 min. ASA 320, Print exposure 15 sec.

Observations

Delta 100: Xtol produced good sharpness, good shadow detail and a roll off in the highlights. Overall the image is a little too dull and flat in the mid-tones and doesn’t have smooth mid-tone separations. Exactol Lux produced the best image. Good shadow detail, lush mid-tones, very sharp, tonal separation through out the print distinct and lush. Pyrocat-HD produced a print close in comparison but the shadows blocked up noticeably more, the tonal separation was not as smooth and lush but still very good especially when compared with the Xtol print. Highlights were very good with good separation.

Personally, I found the Pyrocat-HD print good but not as good as the Exactol Lux print. The Exactol Lux print provides a warmth and tonal separation that Pyrocat doesn’t quite have. The openness of the shadow tones is distinctly better with the Exactol, and interestingly enough, the Exactol Lux seems to convey a slight edge in sharpness throughout. The negative is decidedly thinner and prints much faster too. The film speed with Pyrocat-HD is 1/3 of a stop slower at 80.

Delta 400: Xtol produced good sharpness, blocked shadows and good highlights. Overall the image is a little too flat in the mid-tones and doesn’t have smooth mid-tone separations. Exactol Lux, again, produced the best image. Good shadow detail, lush mid-tones, very smooth tonal range, tonal separation through out the print distinct and lush with excellent highlight separation. Pyrocat-HD produced a print close in comparison with good shadow detail, the tonal separation was not quite as smooth and lush but still very good especially when compared with the Xtol print. Highlights were very good with good separation but not quite as distinct as the Exactol Lux print.

Again, I found the Pyrocat-HD print good but not as good as the Exactol Lux print. The Exactol Lux print provides a warmth and tonal separation that Pyrocat doesn’t quite have. Again, interestingly enough, the Exactol Lux seems to convey a slight edge in sharpness throughout. The negative is a little thinner and prints somewhat faster too. The film speed with Pyrocat-HD is 1/3 of a stop slower at 320.

I also shot a roll of Ilford’s XP2 Plus of the same scene at ASA 400 for comparison. The image is good, sharp but with tonal separation overall flat. Noticeably the highlights separation seems to be lacking punch when compared with the Exactol or Pyrocat Prints. Shadow detail is blocked up too. I have always noticed the skies with XP2 to be a bit grayer when compared to silver based films. XP2 is, however, quite grainless. Still it is not my choice of films.

Other Observations

What is the visual difference between the Delta 100 and 400 prints using the same developer? To my eye there is a little more sharpness and a better mid-tone presentation with a little more life in the highlights with the Delta 100 over the Delta 400.

Pyrocat-HD appears to be a developer with similar characteristics to Barry Thornton’s Exactol Lux but not a direct replacement and not quite as good in all the areas where Exactol Lux excelled. We owe a debt of gratitude to Barry for showing the way and what can be done to achieve inviting prints from small negatives.