HP5+ and high B+F fog workarounds?greenspun.com : LUSENET : Large format photography : One Thread
In a recent post about ULF film, I stated that I am going to explore switching from TXT to HP5 for my banquet cameras. In doing this, I am going to have to address the relatively high B+F levels that this film generates when it is 'pushed'.
In my case, the film will almost always be 'pushed', because I am shooting to use with platinum printing, with a target DR of 1.6 or there about.
I have seen a mention of the use of BENZOTRIAZOLE as a way to help reduce the fog level from this film. Does anyone have any advice on whether this wil work, and how it's done?
I have been using D-76 for my developer, but I also may be forced to change to a pyro or pyrocat developer as part of this film change. Generally, the concensus on the street is that HP5+ shows it's best for platinum in a staining developer.
While I intend to do some testing to determine what my own path to photographic 'nirvana' is, I thought I would elicit comments from the gallery.
Thanks to everyone,
-- Michael Mutmansky (email@example.com), February 28, 2002
Michael, I use Pyrocat-HD for my Pd/Pt negatives. I haven't finished my tests with HP5, but Bergger 200 (which I consider even worse with regard to base fog) looks OK with Pyrocat. I personally feel that the catechol-based pyrocat-HD is an excellent developer with "well behaved" and even staining, and is far superior for the Bergger film than any other developer I've tried, including ABC+ pyro.
I'll be shooting and developing some 8x20 HP5 in the next few weeks and I'll share my impressions.
-- Linas Kudzma (firstname.lastname@example.org), February 28, 2002.
I have noticed reduced base-plus-fog levels with almost all my films when I use Pyrocat-HD instead of PMK. I also understand that many platinum printers find that Pyrocat-HD negatives don't require quite as long an exposure time as pyro negatives. The only problem I have noted with Pyrocat-HD is that the phenidone version doesn't keep very well, but that can be remedied by substituting metol.
-- Ed Buffaloe (email@example.com), February 28, 2002.
Benzotriazole is an organic restrainer. It's very potent, and you only need a few millilitres from a 2% stock solution added to the developer. If you buy it in powder form the solubility in water is very low, and it's difficult to get even a 2% solution (my dear Watson!). It's much more soluble in iso-propyl or benzyl alcohol.
To make a stock Benzotriazole solution you take 20ml of IPA or benzyl alcohol and add it to 50ml of water, and then dissolve 2gms of benzotriazole in that. Then make up to 100ml with water.
You may want to multiply these quantities by 10 to make 1 litre if you plan on using a lot of it. The stock solution lasts for ages.
You only need about 10ml of this stock solution to 1 litre of developer as a powerful anti-fogging agent.
-- Pete Andrews (firstname.lastname@example.org), February 28, 2002.
I have been testing HP-5+ to get N+1 and N+2 expansion for POP. For N+2, I target a zone I density of .1 and a zone VI density of 1.7. N+2 for POP is easy to get with a buffered non-solvant developer, like DK-50. Use DK-50 straight for about 10 minutes and you will have as much contrast as you could want. HP-5+ is foggy in D+76, but it is not foggy in DK-50. The bromide in DK-50 keeps the fog down.
-- William Marderness (email@example.com), February 28, 2002.
For whatever it is worth, I have just not found the B+F to be a problem with HP5+ in Pt printing at 12X20. The big complaint is supposed to be long exposures, and I am getting less than 400 units on a plate burner (a NuArc 26-1K Mercury unit as recommended by Arentz) for the majority of shots when processed in PMK pyro (tray processing 70 degrees, 13 min) and then developed in K Oxalate at 90F. This is about the UV exposure time Arentz says to expect for Tri- X negs processed in a non-staining developer, and is quite close to what I get as an exposure time for Tri-X negs in PMK pyro. I guess my understanding of this is that, unlike most other developers, you don't have to increase the film processing time at all to get a good Pt neg with pyro. I have heard it said, and certainly found it true for dozens of 12X20 negs now, that you can get a neg that prints beautifully in both Silver and Pt/Pd with normal development in pyro. I think it is the additional development time with other developers that you have to use in order to get into the Pt range that makes HP5+ esp "foggy" and annoying to use for Pt. The 13 min at 70F is what is recommended in Hutchings' "Book of Pyro" for standard silver negs. By comparison, I find the time and temp combo recommended for HP5+ in PMK pyro by Sullivan (is it 12 min @ 75F?) to give negs which are too dense, and do take MUCH longer to print, though they still give nice Pt/Pd and even straight Pd results. I'm certainly not seeing any advanage in terms of the final product to going with the "souped up" development recommended by Sullivan and Weese over Hutching's standard for silver negs.
I've not used pyro cat, but I guess will consider it if my situation changes and I get disenchanted w/ PMK pyro.
Don't know how easy pyro cat or benzotriazole are to get or to use, but if there is any hassle factor, I would really consider trying the straight time/temp combos recommended by Hutchings for HP5+/PMK for your Pt negs, and see how you feel about the printing times/B+F results. Obviously, it's quite easy to get and use the PMK kits from B+S, Photo Formulary, etc. Perhaps there is some cost advantage to pyrocat and/or the benzotriazole?
-- Nathan Congdon (firstname.lastname@example.org), February 28, 2002.
In fact, D-76 used in a rotary processor gives the lowest fb+f level for HP5 I've encountered, with the film developed to Pt/Pd contrast levels. These negatives will almost always be too contrasty to print well in silver though. PMK in my lab needs extended development to get sufficient contrast from HP5, and the printing exposure times remain reasonable, though about double what's needed for a thin-base film like FP4 or TXT. Pyro results seem to show abnormal variation from one person's darkroom to another, so individual testing is always required and may give very different results from published sources.
I've been testing Pyrocat HD (in a metol version) and am impressed with the results with several films, but have not yet tried it on HP5. The developer gets contrast easily, with lower base and shadow density than PMK. Also, less tendency to uneven staining--not often a problem with PMK but I've run into it with 1220 negatives in particular. Very smooth sky areas on big negs with pyrocat. I expect it will be a good choice for HP5. Ingredients easily obtained from ArtCraft chemical and other
-- Carl Weese (email@example.com), March 01, 2002.
Thanks all for the responses.
I have been thinking about trying out some of the Pyrocat HD developer myself for the last year, but have not done it yet. I use a rotary processor, and would prefer to continue to do so, and I have heard favorable results with pyrocat for rotary. Not so favorable for PMK, or it's variants.
I will switch to tray processing if I need to, but I would prefet to keep my hands out of the drink.
From the suggestions, I have a few developer combinations that I think I will try, including d-76 and d-76 with the benzotriazole addative, since that is what I am using right now.
*Sigh*, I thought I was done doing step tablets for a while...
If anyone else has any input, feel free to interject your thoughts and suggestions.
-- Michael Mutmansky (firstname.lastname@example.org), March 01, 2002.