D23 & Pyrocat-HD Comparison

Andrew O'Neill · Jun 12, 2018

David Allen said:
I find both very unsatisfactory but that may well be due to the scanning process

I would be very much interested how they actually print on conventional paper.

Bests,

David.
ww.ddsallen.de

I don't print on conventional paper... silver gelatin?. Carbon transfer, mainly and other alt processes.

Ian Grant · Jun 12, 2018

Andrew O'Neill said:
I don't print on conventional paper... silver gelatin?. Carbon transfer, mainly and other alt processes.

But you still need sharp negatives

David was asking about the attached images, and the quality in terms of tones, sharpness etc.

Ian

Gerald C Koch · Jun 12, 2018

pdeeh said:
But at 1+3 the sulfite is at 25g/l, which is at least half the optimal concentration of 50-80g/l for solvent action surely?

(I may be misremembering of course, but I'm pretty sure I got that number from a post of Gerald's )

Yes, the number is about 70 g/l but ever at only 25 g/l the sulfite content is much high than for pyrocat.

esearing · Jun 15, 2018

The thing I have learned about Pyrocat HD is that those who use it as their main developer often explore different dilutions and agitation techniques to work with difficult lighting situations. Normal development is relatively easy with any developer but when you need expansion or contraction of N+or-2, pyrocat begins to shine and is very controllable. Does D23 have similar common use for semi-stand/stand techniques with dilution? What is its shelf life for the infrequent user? Availablility if not mixing own?

Andrew O'Neill · Jun 15, 2018

Divided D-23 is pretty good at handling extreme N- situations. As far as stand/semi-stand development goes, I would think that it wouldn't be a good candidate due to high sodium sulfite content. If you're a Pyrocat-HD user like me, I'd stick with Pyrocat. It's such a versatile developer. Since D-23 is not on the shelves anymore, one has to mix from scratch... which is a piece of cake.
Check out Ken Lee's site: http://www.kennethleegallery.com/html/tech/D-23.php

Eric Rose · Jun 15, 2018

Doesn't the Formulary still sell it??

Andrew O'Neill · Jun 15, 2018

Ian Grant said:
But you still need sharp negatives

David was asking about the attached images, and the quality in terms of tones, sharpness etc.

Ian

Looks acceptable to my eye. My students just developed all their film at 1+3 for 18 minutes (EI 200) and they look very nice. Not as sharp as Pyrocat, though.

Andrew O'Neill · Jun 15, 2018

Eric Rose said:
Doesn't the Formulary still sell it??

Your right it does! Just looked there.... cheaper to mix it myself.

Zelph · Jun 17, 2018

jonasfj said:
They look, if not identical, very similar. It strengthens my belief that the choice of developer has nothing to do with making a good picture.

It does have something to do with safety and comfort to those who develop allergic reactions to metol.

jonasfj · Jun 18, 2018

Zelph said:
It does have something to do with safety and comfort to those who develop allergic reactions to metol.

Yes, for those worried about health and environment, Xtol would be the obvious choice. Pyrocat and Rodinal are downright poisonous. D-76 and HC-110 a little bit less so, but still not good. I would recommend everybody to be careful and treat also Xtol as a chemical, but it is quite harmless.

Ian Grant · Jun 18, 2018

jonasfj said:
Yes, for those worried about health and environment, Xtol would be the obvious choice. Pyrocat and Rodinal are downright poisonous. D-76 and HC-110 a little bit less so, but still not good. I would recommend everybody to be careful and treat also Xtol as a chemical, but it is quite harmless.

There's far worse household items in everyday use in kitchens, bathrooms, etc, there needs to be more realism.

Ian

Anon Ymous · Jun 18, 2018

Uh, Metol might not be the most benign stuff on earth, but Catechol is definitely one of the nastiest developing agents used. It's not that it can't be used safely, but should definitely be treated accordingly.

Ian Grant · Jun 18, 2018

Anon Ymous said:
Uh, Metol might not be the most benign stuff on earth, but Catechol is definitely one of the nastiest developing agents used. It's not that it can't be used safely, but should definitely be treated accordingly.

But then stop bath is dangerous when concentrated, so is house-hold Sodium Hypochlorite based bleach, oven cleaners it's a long list.

It's the mixing Pyrocatechin developers from raw chemicals that's potentially the most hazardous, once in use it's not going to hurt you unless you constantly get it on your skin and don't wash it off immediately. I wouldn't use it for a print developer where I do immerse my fingers sometimes (PQ not MQ) but I do use it in IT-8 toner as the paper's redeveloper with tongues,

Ian

jim appleyard · Jun 18, 2018

Ian, isn't Q rather nasty stuff to be putting your fingers in? Isn't Q related (closely?) to pyrogallol and catechol? They're all benzene rings (?) and those are quite nasty. However, I agree that there are many things in our normal life that aren't good and we should be careful of them all.

Anon Ymous · Jun 18, 2018

Just because a compound has a benzene ring, it doesn't mean that it is inherently very hazardous; phenidone has a benzene ring too, but is much less toxic. For the record, hydroquinone and Catechol are isomers, the position of a hydroxyl group is the difference between them.

jim appleyard · Jun 18, 2018

Anon Ymous said:
Just because a compound has a benzene ring, it doesn't mean that it is inherently very hazardous; phenidone has a benzene ring too, but is much less toxic. For the record, hydroquinone and Catechol are isomers, the position of a hydroxyl group is the difference between them.

Well, you lost me, I am not a chemist. If you say that a benzene ring can be less hazardous that I assume, I will take your word for it.

Anon Ymous · Jun 18, 2018

jim appleyard said:
Well, you lost me, I am not a chemist. If you say that a benzene ring can be less hazardous that I assume, I will take your word for it.

Take sodium benzoate for example. It's a very common food preservative, your soft drink might have a small amount of it.

PS I'm not a chemist either.

Andrew O'Neill · Jun 18, 2018

You guys are taking this waaaaay off topic...

Ian Grant · Jun 19, 2018

jim appleyard said:
Ian, isn't Q rather nasty stuff to be putting your fingers in? Isn't Q related (closely?) to pyrogallol and catechol? They're all benzene rings (?) and those are quite nasty. However, I agree that there are many things in our normal life that aren't good and we should be careful of them all.

Lots of things are nasty, Coke will dissolve your teeth, it's about realism. I use tongs in the darkroom when printing but at times particularly with large prints prefer to use fingers which get rinsed well immediately after.

I ran a lab, I had to do the COSSH assessments, that's risk analysis and putting correct safety procedures in place and we dealt with chemicals far more hazardous than the average photographer will use, so I have confidence in my comments. Everything we use has an MSDS (data-sheet) which should be read. I have grave concerns that many household products don't carry sufficient warnings and they are being used by people with in general no chemical knowledge, particularly in relation to their own safety.

Ian

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