Film hardener?

Photo Engineer · Aug 7, 2010

Ian Grant said:
While there's undoubtedly truth behind that with older Pyrogallol etc tanning/staining developers they were used quite differently to the modern highly dilute developers like nPyrocat and PMK, and weren't suitable for miniature films 120 or 35mm etc. They were often designed to maximise these effects particularly for contact printing.

Non tanning/staining developers can cause similar problems of exaggerated edge effects with smaller negatives which is why some commercial high acutance developers of the 60's annd 70's never became successful and were withdrawn.

Ian

Regarding the first paragraph, none of us can assure anyone that it won't happen in spite of the newer formulations and that is why I advise testing your particular combination if you use 120 and particularly 35mm.

And, regarding the second paragraph, yes, I agree and this is why an entire new series of HA developers was under development at EK when R&D on B&W processing was "shut down". I have had access to some of these formula ideas and hope to bring at least one to fruition.

PE

Robert Budding · Aug 7, 2010

Photo Engineer said:
I have kept pH 6 - pH 9 fixers for several years at working strength, but I have rarely been able to keep KRLF with hardener for more than 1 year at working strength. It was at pH 4.5. I have some fixer tests going at 5+ years for the concentrate and 2+ years for the working strength. I have one in a tray that evaporated and I redissolved it and kept using it though 3 cycles and lasted about 6 months in an open tray this way. This was pH 6.5, roughly the mean of my tests.

Does this help?

PE

It absolutely helps! I can live with a one year fixer life. It's 2X the amount of time that I store XTOL.

Ian Grant · Aug 8, 2010

Photo Engineer said:
Regarding the first paragraph, none of us can assure anyone that it won't happen in spite of the newer formulations and that is why I advise testing your particular combination if you use 120 and particularly 35mm.
PE

Why do you deliberately KEEP making bland statements like this based on unfounded personal opnions.

Of all people on APUG you should know that Pyrocatechin in particular has been in use in developers designed SPECIFICALLY for miniature films (the pre WWII term for 35mm - 120 sizes) since the early to mid 1930's. Some are staining others aren't.

Your opinions obviously differ markedly from those of your former employer Kodak's because they've used Pyrocatechin in a few developers over the years including HC110.

Ian

Photo Engineer · Aug 8, 2010

Ian;

Just because you can show an effect does not happen with a given film does not mean that it may not happen with any particular film, specifically some of the softer varieties of 35mm. That is why I merely suggest testing. This is not an absolute. And, it is not an unfounded personal opinion. I have some photomicrographs that show this effect. It was on older films without the modern hardeners. So, I have some basis for the suggestion that I made that is specific to older film formulations which are still made and are still in use by some.

HC110 was formulated and tested with Kodak films with the new hardener. And, HC110 no longer contains Pyrocatchin. I wonder why? Go here to check it out! Dead Link Removed

PE

Ian Grant · Aug 8, 2010

There have been issues with Kodak developers and new Kodak films/hardeners etc since the 50's and Kodatol, which was withdrawn because of Dichroic fogging, and replaced with a developer based on research from nearly 20 years earlier.

It's more likely Pyrocatechin was removed from HC110 for environmental and safety issues as it's more toxic and this was close to Xtol's launch, and also work on more eco-friendly colour process.

Posting a spurious MSDS means nothing.

Ian

Photo Engineer · Aug 8, 2010

The MSDS shows no Pyrocatechin so it was removed for whatever reason and replaced by a member of the phenidone family IIRC. I agree that it was probably toxicity. I don't even have any data sheets that show it was present in HC-110.

I would hardly call any MSDS spurious, but sometimes they can be misleading as they can omit trade secret data.

PE

Ian Grant · Aug 9, 2010

Photo Engineer said:
The MSDS shows no Pyrocatechin so it was removed for whatever reason and replaced by a member of the phenidone family IIRC. I agree that it was probably toxicity. I don't even have any data sheets that show it was present in HC-110.

PE

The Pyrocatechin (1,2-dihydroxybenzene) was replaced by Hydroquinone (1,4-dihydroxybenzene), to some extent they are interchangeable, it would never be replaced by a phenidone type developing agent. Using Pyrocatechin would give slightly finer grain, it has often been used instead of Hydroquinone in Graphic arts developers, mainly by Agfa (Germany) who's similar Agfa Ansco formulae used Hydroquinone instead, but also by Kodak.

Ian

Sirius Glass · Aug 9, 2010

Alessandro Serrao said:
Not speaking about that hydroquinone is a probable carcinogenic agent...

I cannot enjoy photography unless I am using toxic chemicals.

Steve

Photo Engineer · Aug 9, 2010

Ian Grant said:
The Pyrocatechin (1,2-dihydroxybenzene) was replaced by Hydroquinone (1,4-dihydroxybenzene), to some extent they are interchangeable, it would never be replaced by a phenidone type developing agent. Using Pyrocatechin would give slightly finer grain, it has often been used instead of Hydroquinone in Graphic arts developers, mainly by Agfa (Germany) who's similar Agfa Ansco formulae used Hydroquinone instead, but also by Kodak.

Ian

Ian, it is my understanding that there are 2 developing agents in HC-110. Since I had no reference to the original HC-110, I could not tell whether the Pyrocatechin was replaced by HQ or by a Phenidone derivative. And, I don't have the full formula anyway, just the method of making the adducts.

Sorry.

PE

Gerald C Koch · Aug 9, 2010

Catechol was once said to have been listed in the ingredients for the HC-110 Replenisher which Kodak once made. AFAIK, it was never liisted in the ingredients for HC-110 itself. This is one of those errors that seems to live on without any substantiation.

Gerald C Koch · Aug 9, 2010

Some years ago Kodak researched whether the gelatine in emulsions could be replaced with synthetic polymers. They found that some gelatine could be replaced but not all. The reason they did this was the high cost of photo grade gelatine and its variable characteristics. The result of this replacement was softer emulsions which do not really respond well to hardening baths. I assume that other manufacturers did the same. Because of this some photographers consider hardening baths a waste of time and money.

Gerald C Koch · Aug 9, 2010

Concerning poisons one must remember that it is not only the poison it is also the dosage.

Photo Engineer · Aug 9, 2010

Gerald C Koch said:
Some years ago Kodak researched whether the gelatine in emulsions could be replaced with synthetic polymers. They found that some gelatine could be replaced but not all. The reason they did this was the high cost of photo grade gelatine and its variable characteristics. The result of this replacement was softer emulsions which do not really respond well to hardening baths. I assume that other manufacturers did the same. Because of this some photographers consider hardening baths a waste of time and money.

Gerald;

For a while I worked on this project and another that grafted couplers onto the polymers to reduce coating weight and thickness. The polymers could be made hard, but did not peptize Silver halide the same as gelatin did and therefore there was less support for the grains in the coating. Along with this was the fact that the polymers did not chill set like gelatin (or Jello ) and the polymers did not like slide or curtain coating and caused interlayer mixing.

So, yes, we did a lot of work in that field, some of which did make it to product. Those that did were in products that were hardened to their optimum level.

PE

Gerald C Koch · Aug 9, 2010

Photo Engineer said:
Gerald;
Those that did were in products that were hardened to their optimum level.

PE

Some time ago I read an article on the softness of modern emulsions and their relative lack of response to hardeners. Wish I could find the quote. The article blamed the partial replacement of gelatine as the cause.

Photo Engineer · Aug 9, 2010

Gerald;

Fuji has gone much further than Kodak in this regard but see here: USP 6,153,362, courtesy of Ian Grant on Kodak work. Yes, polymers are difficult to harden! But, not impossible. I found that the effects on coating more profound. Also, in a polymer, the amount of hardening moiety can be varied to optimize the hardening effect.

Some companies use non-hardenable polymers for promoting swell. This is also possible without causing excess reticulation or other softness effects.

PE

Sirius Glass · Aug 9, 2010

Alessandro Serrao said:
Sirius Glass said:

Alessandro Serrao said:

Not speaking about that hydroquinone is a probable carcinogenic agent...

Click to expand...

I cannot enjoy photography unless I am using toxic chemicals.
Steve

Click to expand...

What does it mean?
I hardly can understand your answer, I just don't get the point...

I know that some on the chemicals may be toxic. I am not eating or drinking any of the photographic chemicals. I carefully clear up after I finish.

My car used toxic chemicals.

....

The list is long. So I do not care if one of the chemicals is toxic. After all the digital equipment, if not disposed of properly is even more toxic.

Ciao

Steve

_Craig_ · Sep 20, 2010

2F/2F said:
I use Photo-Flo as directed on the bottle, hang the film, put the film between my forefinger and my middle finger, and then run down the length of it to push off the excess Photo-Flo. Never had a scratch from this method.

Amen to that.

For 50 years I've done the following:

* Pump the film reel in the tank of Photo-Flo so that froth and bubbles scrub off the film.

* Remove the reel and scrub those two fingers against each other in the Photo-Flo.

* Slowly open the door to a nicely painted, vacuumed and washed clean, dust-free closet with no wall cracks, ventilation or heating. Unreel the film as you hang it and attach the weight clip.

* Run your still wet fingers down the film once. (Plump fingers are best

* Slowly exit, slowly close the door, and stay away.

Film hardener?

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