D76 or XTOL. Why?

D76 or XTOL. Why?

  • D76

    Votes: 160 44.1%

  • XTOL

    Votes: 203 55.9%
  • Total voters
    363
James and Higgins got quite a few things wrong about Rodinal; among others is that Rodinal is made from the HBr salt of p-aminophenol, not the HCl salt. That's how the bromide, needed for restraining infectious development, gets into Rodinal. I've done GCMS on Rodinal back to samples from the 1920s and it's remarkably consistent in terms of its manufacture, with some significant abrupt changes along the way.

When I made my own Rodinal for some experiments I synthesized my own P-aminophenol-HBr. It's not exactly easy to do.

Chris101 - if you worked in my lab, you'd have been fired. Someone who hurts themself hurts someone else eventually.

Marty
 
Hey Marty, well then I'm glad I don't work for you! I figure the chemist who has never gotten at least a mild chemical burn is either inexperienced or a theoretician. Which is the same thing, eh?

Can you clarify for me how your GC-MS results can tell the difference between dissolved PAP-KBr and the base with added KBr in a KOH solution? Since J&H doesn't mention the formulation of Rodinal, I fail to see what they "got wrong".
 
Chris101 said:
Hey Marty, well then I'm glad I don't work for you! I figure the chemist who has never gotten at least a mild chemical burn is either inexperienced or a theoretician. Which is the same thing, eh?
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Unfortunately, in some ways, we operate in an environment of very heavy surveillance and regulation. In Australia, theoretically, although it would be very unlikely to happen, you can be prosecuted for breaches of occupational health and safety for injuring yourself. Many employers, especially those who are self-insured, are incredibly intolerant of even minor breaches of safety controls. It's just how it is.

Chris101 said:
Can you clarify for me how your GC-MS results can tell the difference between dissolved PAP-KBr and the base with added KBr in a KOH solution?
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Ratiometrically: there will be some minor variation because of manufacturing variation using tech grade photo chemicals between the concentration of PAP and Br if the latter is added separately. In the samples I tested the ratios are statistically so close to 1:1 as to be almost impossible to achieve using mass manufacturing techniques. If the manufacturers QA is very tight, it could be achieved using PAP base and KBr, but PAP base is much more expensive than its salts and photo chemicals all have a reasonable amount of manufacturing variation. In terms of industrial chemical manufacture, their tolerances aren't very tight. But our lab makes analytical standards, so my idea of normal variation is pretty skewed.

Chris101 said:
Since J&H doesn't mention the formulation of Rodinal, I fail to see what they "got wrong".
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My 19_4_8 edition has a formula which is Rodinal-like, but isn't really. Sorry, I just noticed that you used the 19*6*8 edition, which I don't have.

Take it easy and stay safe,

Marty
 
Ok. I still don't buy the PAP-HBr complex - it's more expensive than the base (PAP-HCl is about the same mole-for-mole as the base. Bromides are WAY more expensive than chlorides in general.) I can't disprove it, and I don't believe that your experiment has proved it. However, you find your results compelling, which says something in favor of your hypothesis.

Unfortunately, at this point we'd be lucky if there was a single other person here who cares what we are talking about. But I'm intrigued by your experiment, and I'd love to know more, but I don't plan on visiting Australia any time soon. (Not to mention that I'd probably spill lye on everybody! 😉 ) If there is anything published about this, please send me a pointer by PM.

You take 'er easy too Marty!
 
Chris101 said:
Ok. I still don't buy the PAP-HBr complex - it's more expensive than the base (PAP-HCl is about the same mole-for-mole as the base. Bromides are WAY more expensive than chlorides in general.) I can't disprove it, and I don't believe that your experiment has proved it. However, you find your results compelling, which says something in favor of your hypothesis.
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I wondered about that but couldn't find any sources for quotes on industrial volume PAP salts. Br salts are always more expensive, yes, but the way that a Br and Cl containing solution restrains development will be different to that of one containing only Br. Activity is important when manufacturing a developer.

Chris101 said:
Unfortunately, at this point we'd be lucky if there was a single other person here who cares what we are talking about. But I'm intrigued by your experiment, and I'd love to know more, but I don't plan on visiting Australia any time soon. (Not to mention that I'd probably spill lye on everybody! 😉 ) If there is anything published about this, please send me a pointer by PM.
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This was all done for my own interest and isn't published. If you visited you could see the lab but I wouldn't be able to let you touch anything anyway, because as a non-employee or student you would not be insured. That's how serious we have to be about it.

Chris101 said:
You take 'er easy too Marty!
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Watch those concentrated alkalis and stay safe.

Marty
 
Just let me clarify: always obtain the MSDS for materials you are working with and follow the recommendations about preventing exposure. If recommended, wear gloves, a mask and goggles when handling developers. Work in a well-ventilated area and wash any spills immediately and thoroughly.

Marty
 
Chris101 said:
I agree Chris. For the one doing the developing, personal protective equipment is a must, as their exposure is thousands of times greater than is environmental exposure. A dust mask and nitrile gloves are essential. Chemical splash goggles (ANSI Z-81 compliant) should be used with highly alkaline solutions such as Rodinal. I always tell my (chemistry) students the first time they use it, "If you get sodium hydroxide in your eyes, take a quick look around, because that will be the last thing you see."

Speaking of Rodinal, I cringe at it's popularity. The main ingredients are sodium hydroxide and hydroxyaniline. The former, sodium hydroxide is a contact hazard - it'll cause your skin to crack and bleed, especially with multiple exposure. It feels like soap on your skin, because it is dissolving the fatty acids out of your cells, and making soap out of you.

Hydroxyaniline (aka para-amino phenol) is toxic in very small doses, and can be absorbed through the skin. The symptoms of a small dose are nausea, and loss of fluids. A large dose is usually fatal. It biodegrades very slowly, and is toxic to aquatic animals as well as the microorganisms that are used to break down sewage in waste treatment plants. Nasty, nasty stuff.
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Well, as ever, a lot depends on concentration. As VIth formers in the mid-to-late 60s, in the Biology and Science VIth (Biology-Chemistry-Physics and Maths-Chemistry-Physics), my chums and I were exposed to some pretty frightening stuff, and we weren't always careful (hell, we were teenagers). I remember my room-mate at school spending a day or two in Plymouth Eye Hospital, I think for NaOH exposure but it may have been the result of throwing metallic sodium in the sink. When I went to see him, they said, "Are you his brother?" As I'm large and (in those days) hard dark red hair, and Dave was small and dark, I remember reporting the story afterwards (to widespread laughter), "But then, it was an eye hospital."

Or to quote Mike Gristwood, late of Ilford, "There are things you worry about your kids doing, and things you worry about doing yourself." Neither Mike nor I would counsel for a moment against taking sensible precautions, but there is always the question of when 'sensible precautions' tip over into paranoia (in the colloquial sense). See http://www.bbc.co.uk/news/world-12860842

Cheers,

R.
 
Chris101 said:
Unfortunately, at this point we'd be lucky if there was a single other person here who cares what we are talking about.
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Actually, I've been getting really bored by RFF of late, and discovering this thread has absolutely made my evening. Thanks, guys! 😀
 
Freakscene said:
...always obtain the MSDS for materials you are working with and follow the recommendations about preventing exposure. If recommended, wear gloves, a mask and goggles when handling developers. Work in a well-ventilated area and wash any spills immediately and thoroughly.
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This is not a joke, folks. Those of us who deal with chemistry for a living will do no less, and amateurs shouldn't, either. If you're dealing with toners and the like, all of this goes double. There are some nasty, highly toxic things residing in many darkrooms.

You don't have to be afraid, but you don't have to be stupid or foolish, either.
 
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Some great info in this thread. I use Rodinol a great deal and I'm going to snag some goggles after reading this. My eyes are crappy enough as it is 😉
 
I have found that XTOL gives nice tight grain with Ilford Delta films and with Neopan. D-76 gives more of a "classic" look -- and by classic I mean medium contrast, medium grain more of a 1960s/1970s look. I like that look sometimes -- it is the look of my childhood and of the pictures on which I "learned to see." But I don't always love it for my own work. I have D-76 -- I use it, and divided D-76 when desired. But I prefer XTOL for the reasons Freakscene set forth above.
 
I feel I can't really vote because I have never used D76. I use XTOL more and more and it lasts easily a year+ in the fridge in well filled bottles. I have always used filtered water for the set up. Apart from the fine grain, excellent results and easy processing I like the fact that it appears to be more friendly to the environment.
 
i like xtol for its flexibility (ability to push while retaining fine grain, but i like d76 for its tone, works great with classic films like plus-x and tri-x)

raytoei
 
There is nothing wrong with D76, but XTOL gives slightly better shadow and highlight detail. Also somewhat finer grain.

that said I prefer divided d76 over either....
 
I feel strongly both ways

I feel strongly both ways

I have used both over the years and haven't made up my mind. I like the classic tonality of D76, but the finer grain and extra shadow detail of XTOL is nice. I'll try to post some images that demonstrate the above.

That being said, I recently went back to TMAX developer. I have a love/hate relationship with TMAX developer and Tri-X film...
 
sazerac said:
I have used both over the years and haven't made up my mind. I like the classic tonality of D76, but the finer grain and extra shadow detail of XTOL is nice. I'll try to post some images that demonstrate the above.

That being said, I recently went back to TMAX developer. I have a love/hate relationship with TMAX developer and Tri-X film...
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I second that. D-76 for tonality, XTOL for shadow detail, extra speed, and fine grain.
 
Maybe not a fair comparison

Maybe not a fair comparison

Alright, hopefully these are good representations. Unfortunately all were shot with different lenses...

U37863I1317052908.SEQ.0.jpg

Tri-X in D76 (OM 85/2)

U37863I1317052911.SEQ.0.jpg

Tri-X in TMAX (50 Summicron)

U37863I1317052913.SEQ.0.jpg

Tri-X in XTOL (35mm Ultron)

All in all there are probably more factors involved than just developer. I've always shot Tri-X at 250, but have used several different developers over the years. I don't recall one that was noticablly off - only that D76 looses a lot of shadow detail. Its a lot easier to put more contrast in than take it out.
 
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