Development by inspection: Pinakryptol green, pyro, etc.

I have some questions about development by inspection(DBI), specifically regarding "pyro" developers, Pinakryptol green/yellow. I would greatly appreciate your responses and insights...

The "Darkroom Cookbook" mentions pyro developers being especially well suited for DBI due to the tanning action of the developer reducing the sensitivity of the film emulsion. Would a film, Tri-x for example, become as desentitized after partial development in a pyro based developer as would a film treated with Pinakryptol? Would this effect be extended to Pyrocat HD?

I can't find Pinakryptol "Green" anywhere. Does anyone know of a source?

Can Pinakryptol Yellow only be used as a pre bath, or is it possible to mix it in with some developers as with Pinakryptol green?

Do desensitizers have any effect on film speed?


Long, multi-layered question, yes. But I do appreciate your help.
Many thanks!

I have some pinakryptol yellow, but haven't used it yet. I have discovered that DBI works fine with very weak light for all the (sheet) films I use, up to ISO 100. This is without desensitation. I have used pyro-, pyrocat-. metol-, MQ-,PQ-, and metol/glycin-developers (!).

Some of the "slower" developers show a little fog, but this can also be considered a kind of post-flashing, and so increases shadow detail a little. My inspection light comes from imperfect ligh-proofing of the darkroom. So if I use very slow-working developers, I cover the tray with the lid of a paper box between agitations.

Pinakryptol yellow is used in FX-2 as an antifoggant; it is probably not present in TFX-2. I have not yet bothered with mixing mine with pinakryptol either.

A little OT

Ole said:

SNIP
I have discovered that DBI works fine with very weak light for all the (sheet) films I use, up to ISO 100. This is without desensitation. I have used pyro-, pyrocat-. metol-, MQ-,PQ-, and metol/glycin-developers (!).

My inspection light comes from imperfect ligh-proofing of the darkroom. So if I use very slow-working developers, I cover the tray with the lid of a paper box between agitations.
end snip
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Ole,
What wattage/color light would you recommend DBI?

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Check Michael & Paula's web site for more information on DBI.

MMfoto said:

I have some questions about development by inspection(DBI), specifically regarding "pyro" developers, Pinakryptol green/yellow. I would greatly appreciate your responses and insights...

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I notice that you are a 35mm RF person. Are you contemplating using DBI on your 35mm?

DBI is primarily a sheet film developing technique.

Tom Hoskinson said:

I notice that you are a 35mm RF person. Are you contemplating using DBI on your 35mm?

DBI is primarily a sheet film developing technique.

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Busted. Never the easy road for me. I'd like to try it for 35mm, and I do have ambitions for LF in the future.

Nothing wrong with trying it out on short pieces of 35mm. Just choose subject matter with ease of evaluation in mind.

Tom Hoskinson said:

Nothing wrong with trying it out on short pieces of 35mm. Just choose subject matter with ease of evaluation in mind.

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My intention with 35mm has been to develop the roll to, say, the half way point. Run a water stop bath. Inspect the roll, and if necessary cut into minus-norm-plus sections and develop accordingly.

I think in practice I would enjoy simply being able to inspect for gross exposure errors. Robbing the fixer of it's share in the decision making process.

Sounds like an interesting exercise. A water bath can also be used to control contrast (an Ansel Adams technique). Based on what you see in the inspection after the water bath, you could also change developers.

Bruce (Camclicker) said:

Ole,
What wattage/color light would you recommend DBI?

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I use daylight leaking in through the "blackout"...

But I also use a Kaiser "Dukalicht" with 15W bulb and green filter at about 5' distance - when there's no daylight. That one I only turn on when I want to inspect.

Basic Scarlet N

In the May/June 1991 is of Photo Techniques..then known as Darkroom and Creative Camera Techniques..Mr Kevin M. Pernicano, Ph D. had an article published on this subject. The title was "Developing by Inspection in Bright Light. He covered a number of the desensitizing agents. He develops by inspection. He is a worker in large format. His personal favorite is Basic Scarlert N. He states that the prebath cost approx. 5 cents per liter to make.
The dye is not sold commercially. It is compunded from two chemicals that are available: Safranine-O and Chrysodine. He states that these items are available from Aldrich 1-800-558-9160 or Sigma chemical 1-800-325-3010. He also states that purchasers into today's legal climate may have a problem with aquiring these chemicals from Aldrich or Sigma. He further states that Antec 502-636-5176 is willing to procure and sell small quantities of these ingredients.

He makes a stock solution of 1 gram of each chemical mixed together in a liter of water along with one drop of 10% thymol solution for a preservative.
His working solution is 10ml of this stock into a liter of water which he uses for 2 minutes as a prebath He says that a wide variety of sheet films including Tmax works well in this prebath. He says that it works best with MQ developers...Metol and Hydroquinone. He says that he recommends, due to fogging , it NOT being used with ANY pyro developer. He uses normal stop and fixing baths.

He advises the use of surgeon's gloves because the materials are suspected of being carcinogens. He advises the use of reflected light using a number 3 filter in front of a 25 watt bulb at a distance of 2 feet.

I shoulkd make it clear that I have no experience whatsoever in developing by inspection.

I hope that this information is helpful to this forum.

Claire Senft said:

I hope that this information is helpful to this forum.

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Yes, thankyou, that is very helpful.