Density ranges on Azo, FP4--Pyrocat HD

[Donald Miller]

Several weeks ago I conducted tests on grades two and three Azo printing a Stouffer 21 step tablet and reading the resulting reflection densities using a 310 Xrite TR densitometer. The tests indicated that grade two Azo has a density range of 1.60 and that grade three Azo has a density range of 1.10.

I then conducted tests on FP4 (PhotoWarehouse ISO 125 film) using Pyrocat HD 2-2-100 to arrive at development times that would provide a negative of that density range. I did this by once again exposing a Stouffer 21 step tablet and the resulting transmission densities were read using the blue channel of the same densitometer.

My times for net negative density of 1.60 are as follows:

N-2 Development (9 Zones contracted to 1.60) -- 6 minutes: 15 seconds
N-1 Development (8 Zones contracted to 1.60) -- 7 minutes: 45 seconds
N Development (7 Zones to 1.60) 11 minutes: 45 seconds
N+1 Development (6 Zones to 1.60) 16 minutes: 45 seconds
N+1 1/2 Development (5.5 zones to 1.60) 27 minutes: 30 seconds

Development temperatures were 70 degrees. Film was exposed at EI 125 using incident metering. I have found that my corresponding reflective meter readings using a Zone VI modified Pentax digital meter were EI 64. The negatives were brush developed in trays.

I have just finished printing 6 negatives that had been developed with varying contrast ranges (N to N+2) and they have printed with greater ease then what I had accomplished by relying solely on DBI.

These results were accomplished using my equipment in my system and your results may vary.

 

[sanking]

Donald,

For clarification, papers have exposure scales (ES), not density range. In practice what we want to do is match the DR of a negtive to the ES of the paper.

I am surprised how close your times for FP4+ with brush develoment are to my times with rotary processing for the same DR. For example, using the SBR method, when shooting for a DR of 1.6 I need the following times wiht the 2;2:100 dilution oif Pyrocat-HD at 70F.

SBR 10 5:00 minutes
SBR 9 6:30 minutes
SBR 8 9:15 minutes
SBR 7 11:00 minutes
SBR 6 14:00 minutes
SBR 5 19:00 minutes

These are the times I use with FP4+ for kallitype and palladium negatives. I am really surprised that you need a negative with this much density range for AZ0. I wonder if this isthe experience of other AZO printers?

Sandy

 

[Donald Miller]

Sandy,

Thank you for informing me of the correct terminology for the paper. It makes it much easier when everyone is speaking in the same terms.

As you will recall I exposed a Stouffer tablet on both the grade two and grade three Azo papers. I sent you the densities and corresponding steps and on the total of 1.87 range (grade two) you indicated that your program indicated a 1.60 density range for the negative. This corresponded to my trial and error early attempts (I had found that the grade two Azo would print above 1.54 from a negative that I had). Grade three Azo showed a total of 1.35. I would imagine that this would place the desired negative density range in the area of 1.10.

After the testing with the step tablets I then shot film to determine if my actual results matched my darkroom testing. For all practical purposes the densities of my camera negatives were in line with my step tablet exposures and development times (so long as my metering was consistant).

This afternoon I printed those negatives and the density range of the negatives matched both grade two and grade three paper very nicely. In fact these are the best Azo prints that I have been able to produce to this point.

While I can't speak to other's experiences, I am comfortable that the paper characteristics (as tested) are consistant with what my actual experience in producing prints.

As an aside another photographer on the Azo forum had indicated a 1.48 density range in his testing. I am not sure that he did reflection testing of the paper to determine that value though.

 

[sanking]

Donald,

As a point of information, were your negative readings with the X-Rite 361 made with the Visual, Ortho(Blue), or UV channel?

Sandy

 

[Donald Miller]

Sandy,
I read the densities with the blue channel on my Xrite 310. That model does not incorporate a UV channel.

Additionally, In the Technical Gallery I have posted two of the images that I printed this afternoon. The grade three print has a negative DR of 1.12 and the grade two print has a DR of 1.64. I realize that images presented in this manner are inadequate but perhaps these will give some indication.

 

[Francesco]

Sandy,

Have you made tests for SBR > 10 (e.g. 11, 13, 15)? Which dilution would you be using in such cases in order that development times would not be ineffectively low? BTW, would the same apply to gentle agitation using BTZS tubes?

 

[sanking]

Francesco,

For SBR of more than 10 I would recommend the 1:1:100 dilution of Pyrocat-HD. Develoment times for high SBR values would be too short in my opinion for the 2:2:100 dilution.

I have test data up to SBR of 13, with DR of 1.6, for Pyrocat 1:1:100 with Ilford FP4+. BTW, amy testing method is based on the standard of gentle agitation in BTZS types tubes. Here is the information.

SBR 13 3:00
SBR 12 4:15
SBR 11 5:30
SBR 10 6:30
SBR 9 8:00
SBR 8 10:00
SBR 7 15:15
SBR 6.5 20:00

For this high a DR (1.6) I don't recommend the use of the 1:1:100 dilution for SBR values of less than 7 (or for any N- development).

 

[sanking]

Donald,

To avoid any misundersteanding the SBR/time values I gave for both the 2;2:100 and 1:1:100 dilution of Procat-HD were based on UV readings, not blue channel. That is because I am testing for kallitype and palladium printing which are sensitive primarily to UV light.

In general I would need to substract about log 0.30 from my UV reading to approximate the blue reading. So in effect if your readings are giving you a density range of 1.6 with the blue channel reading this would be an effective DR of 1.9 or more for me with a UV reading. Did you check the results with your X-Rite 361 in UV mode?

 

[L Gebhardt]

Slightly off topic, but how do you use a step wedge in testing a negative? I have used mine for paper, but don't know to accurately expose film through it.

 

[Francesco]

Thanks Sandy. I have ordered the kit from PFormulary and I will be receiving it very soon. The film I will be using is Efke PL100 8x10. I have exposed some negatives that had a low EV of 9 to a hi EV of 17 and 18. I will let you know how it goes.

 

[Donald Miller]

Donald,

To avoid any misundersteanding the SBR/time values I gave for both the 2;2:100 and 1:1:100 dilution of Procat-HD were based on UV readings, not blue channel. That is because I am testing for kallitype and palladium printing which are sensitive primarily to UV light.

In general I would need to substract about log 0.30 from my UV reading to approximate the blue reading. So in effect if your readings are giving you a density range of 1.6 with the blue channel reading this would be an effective DR of 1.9 or more for me with a UV reading. Did you check the results with your X-Rite 361 in UV mode?

Sandy,

As I have indicated my density readings were taken with an Xrite 310 densitometer (does not have a UV channel). I initially read the reflection densities of the Stouffer tablet exposures on Azo grade two and grade three. From that I was able to gain the ES of the paper. I then tested to gain an equivalent DR on my negatives by again exposing a Stouffer tablet and reading the negative densities through the blue channel.

I had emailed you with the results of my reflection testing and you provided me with the 1.60 DR based upon my step tablet readings for Azo grade two. We had decided that probably the UV readings were not applicable when one exposes the Azo with a 300 watt reflector flood (I imagine that this source is very low in UV output). I believe that you indicated that while Azo's primary spectral response lies in near band UV it will expose to visible light in the blue spectrum. Apparently that is what occurs with the reflector floods that are widely used by Azo printers.

I don't know of anyone that is exposing Azo with a UV source since the exposure times are generally acknowledged as being too short to be manageable. I did find yesterday that I will be able to drop back to a 150 watt reflector flood since my exposures ranged from 6 to 11 seconds with the 300 watt reflector flood lamp. I acknowledge that this is a further indication of the beneficial lack of general stain with Pyrocat developer.

I think that the type of light source and amount of UV output may very well be the basis for the discrepency that you seem to question.

 

[sanking]

"Slightly off topic, but how do you use a step wedge in testing a negative? I have used mine for paper, but don't know to accurately expose film through it."

The procedure I use is based on the BTZS testing system developed by Phil Davis for his Zone System workshops and described in the last several editions of his book Beyond the Zone System.

Basically you expose five or six negatives to a step wedge, develop them, and then read and plot the film densities. Each negative gets the same exposure but a different time of development, ranging from about 1/4 to twice or three times of what would be considered normal development. I use 4X5" Stouffer step wedges for film testing.

One of the keys to this system to the ability to accurately expose film consistently. Many people use their enlarger and timer for exposure and that works fine if you can expose accurately at about 1/10 to 1/5 of a second. Exposures longer than 0.5 seconds should be avoided because of reciprocity. However, if one really wishes to make any meaningful comparison of relative speed between films you must have a more accurate exposure system than most darkroom timers allow. For my tests I use a Metrolux light integrator/timer that provides accuracy to about 1/100 of a second.

 

[L Gebhardt]

Sandy, thank you. I will look this up.

 

[Francesco]

Sandy,

I have just developed my first Pyrocat HD 8x10 neg (PL100). As the SBR was 10 I used a dilution of 1:1:100 @ 22C, 6m30s as per your suggestion above. I do not own a densitometer so I cannot prove what I see BUT the negative looks stunning! It looks easy to print (have not printed it yet) and would probably be interpretable in both Pt/Pd and Azo.

I developed a duplicate negative using TMAX RS 1:15 @ 22C, 13min (a recommendation by John Sexton for up to N-3) but I got zip. Maybe a bit more than zip. The negative was almost clear film. Strange that when held up to the light I could swear that I could see a very faint positive representaion of the negative. Nevertheless, there was nothing in this negative that could even come close to the detail in the Pyrocat HD negative.

Many thanks!

 

[sanking]

Francesco,

Congratulations on your good work with this difficult lighting condition. I am very pleased that my development recommendations for FP4+ and Pyrocate-HD have proven useful to your work. Pleae let me know if you have further questions.

 

[Francesco]

Sandy,

Thank you for those encouraging words. I do have more questions but one in particular caught my interest. Should I be looking for some kind of "stain" or "colour" on the negative? I have to admit that being a novice on pyro I cannot identify anything unusual on the negative in relation to "stain" as discussed in many threads here and elsewhere. The one thing I can say is that it looks like PYROCAT can go much further than just SBR 10 (no other non-pyro developer I have worked with could achieve more than an 8 or 9) and that what you get is very clean highlights and extreme detail in the shadows even in subjects that are far away. I have four negatives that have SBRs of 13 and I will be doing them tonight with PYROCAT (as opposed to uising my "new arrivals" of TFX-2 and Modified POTA, which I thought would serve as my back up - dont think I want to sacrifice negs on them now!).

BTW, the film I used is Efke PL100.

 

[sanking]

Francesco,

Your comment about the look of your Pyrocat negatives, i.e. that you cannot "identify anything unusual on the negative in relation to "stain" as discussed in many threads here and elsewhere" is typical of the reaction of many persons using Pyrocat-HD for the first time. This is due to the fact that the stain produced by Pyrocat-HD is typically brown, or even brownish-black. Photographers who have previously used developers like PMK and Rollo Pyro nearly always underestimate the intensity of the Pyrocat-HD stain because by comparison with the green or greenish/yellow stain of these developers the brown Pyrocat-HD stain looks almost neutral in color. This is not the case, however, and in practice it will be found that the brown stain of a Pyrocat-HD negative will have an impact on the effective printing density of the negative that is as great, or even greater, than the green and greenish/yellow stain of other Pyro developers.

The impact of stain is a very complicated issue and one that, from my perspective, only a handful of people really understand. I am completing at this point a rather long article on Pyrocat-HD that will go up on Ed Buffaloe's UnblinkingEye. com site soon, hopefully within the next few days. In this article I address the question of stain and its impact on varius printing processes. Look out for it as I think you will find some of my opinions on this matter interesting and useful.

 

[Jeremy]

sandy,
will this article include your suggested times for different films? people are always asking about times for different films and if there was one main source you could point them to it might help with a lot of confusion. I've been looking through a number of archives across the net for suggested times for HP5 (which include a range of SBR's, not just the "normal") and have found a geat deal of information but have trouble separating them into times for azo, pt/pd, or enlargement on silver, which dilution they are at, and the film speed to shoot at. I know I need to be doing my own testing, but I haven't even been able to get into the darkroom since my last postcard (quite a while ago).

note: Francesco's question is definitely one that needed to be asked directly as it concerned more extreme SBR's than usually used.

 

[sanking]

Jeremy,

I will be including CI (Contrast Index) charts for all of the films that I have personally tested with either Pyrocat-HD 1:1:100 or 2:2:100. Further, there will be two kinds of charts, one based on UV reading which would be appropriate for alterenative printing with UV light, another based on Blue channel reading which would be more appropriate for AZO and graded silver papers, and with some minor adjustments, for VC papers.

 

[Francesco]

Sandy,

I have now developed for SBRs of 11 and 13 (5m30s and 3m respectively). I still cannot believe how versatile PYROCAT HD is (and quite economical at 1:1:100 for these extreme SBRs). The negs look like they have been developed normally. In fact, I feel as if these scenes are not as extreme as I had thought when I took them. Your suggested times are spot on and I do not hesitate to recommend them using Efke PL100 8x10. A wonderful and easy combination! My next project is to try Classic 400 once I take a few more on PL100: Thank you very much once again.

 

[Francesco]

I also followed your advise concerning a presoak in distilled water for about 2 to 3 minutes (BTZS tubes). I am very happy with the results!!

 

[Francesco]

Sandy,

I decided to test the 2:2:100 dilution on a negative which had an SBR of 9 (the film is still Efke PL100), using a time of 6m30sec. Although the negative was nicely developed, it did not have that extra glow I saw in those negatives which I developed using a dilution of 1:1:100 (SBR of 10, 11 and 13). I tried once more using another negative but still the same result. Not as much punch as the others. Is there any reason why, for this film, I should not standardise on a dilution of 1:1:100? Do you think that some films behave better at dilutions of 1:1:100 for all SBRs (e.g from 7 to 13) than others? Does your forthcoming address the issue (if there is one) of matching films to PYROCAT HD dilutions?

I have another set of negatives which I shall develop at 1:1:100 to see if returning to this dilution brings back the "punchiness".

 

[Donald Miller]

Francesco,
At the risk of stealing Sandy's thunder, it is not a matter of matching films to Pyrocat dilutions so much as matching dilutions for desired density ranges in the negatives. 1-1-100 dilution is typically used for negatives designed for enlarging. (DR of 1.00). The 2-2-100 dilution is designed for negatives that have higher desired density ranges (Azo, Pt-pd, Carbon etc.) I am not sure what you are doing with your negatives. This is a general explanation.

 

[sanking]

Francesco,

In my own work I have not noticed any difference in "punch" between negatives made with the 1:1:100 dilution and those made with the 2:2:100 dilution. Using the short times that are needed for developing with SBRs of 9 and greater we would expect to see less staining than with the longer times, and you would have less staining with the 2:2:100 dilution than with the 1:1:100 dilution, other things being equal. This may be what you are experiencing.

My article does not address the issue of matching films to a specific dilution. That would be an enormous undertaking that would require extensive testing, printing, and print evaluation. What I would basically recommend is that alternative printers use the 2:2:100 dilution for all SBRs of 7 and less, and the 1:1:100 dilution of SBRs of 8 and more. I recommend the 1:1:100 dilution for all forms of projection printing. This is of course consistent with Donald’s comment that “it is not a matter of matching films to Pyrocat dilutions so much as matching dilutions for desired density ranges in the negatives.” And to a certain extent my recommendation is based on the desire to keep development times at more than five minutes whenever possible, and not on the fact that I have found any advantage in one of the dilutions.

 

[Francesco]

Thanks for your comments. How would you describe the "look" of a negative with more staining? I was being very subjective in describing one as punchier. An objective description would be that the negative developed with the 2:2:100 dilution had a marked difference in appearance to the one developed in the 1:1:100 which may be related to some increase in density I have not seen before. Thanks again.