Is there any possible (math/chemistry) calculation? Going from HC-110 data to D-76 data: from HP5+ to Tri-X...

I got only two TX rolls left, inside two cameras, and from now on it'll be HP5+ exclusively, because I liked HP5+ in HC-110 very much, so I got enough of both for the next three years.
When I did tests last month for TX in HC-110, I didn't like that as much as TX in D-76...
I have lots of own times for my TX at 320 and 640, in D-76 stock, 1+0.5 (that's Eugene Smith's 2:1), 1+1, and 1+1.5 (great for 120, as it's 240ml+360), but all those are for overcast, as I have never needed to expose TX under direct sunlight...
Summer's just begun, and yesterday I had to do some street scenes under direct sunlight, inside one of those TX rolls I had used for a week for overcast at 320: a roll I was expecting to develop for a common expansion as always, with a (kind of) long development in D-76, as I like sharp visible grain.
All that to explain now I'll have to develop that TX roll as a direct sunlight one (more diluted solution, reduced agitation), but I never did that with TX before. Of course I'll have to treat the soft scenes inside that roll, with higher contrast filters to make them reach normal printing contrast.
As I'm full of HC-110, Perceptol and Microphen, I won't buy more D-76, and all I got left of it is an amber glass bottle of 500ml, so I can't waste it, as I have precisely two rolls to develop, and I use 240ml for each roll.
As you can see, it would be great if I had a time for diluted D-76 for sunny scenes very generously exposed for the shadows: I used 1/125 f/5.6 with TX because that's my final exposure for sun with HP5+ when sky is blue and shadows are really dark, without clouds filling them at all. I used f/8 for some time before final calibration, but a stop more made possible direct prints with very open shadows.
So, considering HC-110's very common dilution B (1+31) is close to D-76 1+1, and considering my HC-110 calibration for HP5+ was 1+31 for overcast, and 1+99 for sun (complete data in a moment), would you say it's possible to stablish a diluted D-76 time for sun with Tri-X, FROM a common 1+1 time for standard contrast scenes?
Then: while my overcast time in HC-110 for HP5+ EI320 is 1+31 21C (11ml for a total of 352) 6 minutes, with 2 inversions in the beginning, and 2 inversions every minute, my direct sunlight time in HC-110 for HP5+ (1/125 f/5.6, incident in the shadows @320) is 1+99 21C (6ml for a total of 600) 10 minutes, with 2 inversions in the beginning, 1 at minute 3, and 1 at minute 6...
Now we can say when with HP5+ in HC-110 I go from overcast to sun, I use 6ml instead of 11ml (a bit more than a half), I use a final volume of 600ml instead of 352ml (12 7ths), I use 10 minutes instead of 6 (a 66% more time), and I go from 12 inversions to 4 inversions (a third).
Would you say these differences can be used to find, from a D-76 1+1 overcast time, a decent time for sun at 1/125 f/5.6?
I think, asking who's doing sun with TX/D-76 at 1/125 f/5.6 for direct printing, would mean even less answers...
Thanks. This isn't as complicated as it sounds.

That could be tough. I use 1/125 F5.6 in full sun for ISO 25 films, so I think you have grossly overexposed Tri-X by 3-3.5 stops.
I looked through all the Kodak data books I have, and while they give times for pushing the film, none give times for pulling.

Ilford does however, and suggests a time for HP5 exposed at ISO 50 or 100 at 9 min (@20°C) in Perceptol. Fortunately for us, in all the times I can find for TXP, Perceptol = D76 (1:1). So perhaps try 8-9 min @20°C in D76 (1:1)?

My 1977 version of the Kodak Dataguide has the "developing computer" and if I put in D76 1:1 and say I want to develop for low contrast, it suggests a time of 7 min. However, I know that TXP has been reformulated a number of times between 1977 and now, so I don't know how valid that data is.

The 2007 Tri-X datasheet says 12-3/4 min for TXP 320 and 9-3/4 min for TX 400 in D76 1:1. The 1977 version says 10 min for both in D76 1:1, all at normal contrast.

Hi Craig, thanks for your answer.
Exposing under direct sunlight (ISO400 B&W film) at 1/125 f/5.6 is not overexposing: it's just what you do when you meter at 320-400 under overcast skies. It's the same metering. We expose for the shadows, and then it's the very soft development what places direct sunlight areas where they should be.
The type of exposure you talked about for ISO25 is not a correct exposure, but a huge underexposure for the shadows: one that's close to color slide film shadows look: nearly no detail.
Obviously I talk about direct printing: the type of printing that shows us where our process is. No doubt you can -when your process is not optimal- burn in highlights, and give shadows less enlarger light to open them, as negative holds detail in the shadows for that.
If you expose HP5+ under direct sunlight at f/5.6 1/125, and process it in HC+99 (6ml for 600), 21C 10 minutes with minimal agitation, you'll be surprised...
And I'm talking about current MG Ilford paper and dektol.

One more basic fact for this calculation:
Both in HC+31 (B) and in D-76 1+1, HP5+ requires a third more development time than Tri-X.

Having used TMax for ages, I just switched back to Tri-X after many years. My first roll in HC-110 was over developed. Using Dilution B (1:31) the Massive Development Chart indicated seven minutes, or about twice as long as the Kodak Data Sheet indicated. I did a roll today and used Dilution E (1:47) for six minutes and it looks about right.

Juan Valdenebro said:

One more basic fact for this calculation:
Both in HC+31 (B) and in D-76 1+1, HP5+ requires a third more development time than Tri-X.

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So isn't that the basic formula that your thread seeks? Congrats, you've found it yourself

pentaxuser

madNbad said:

Having used TMax for ages, I just switched back to Tri-X after many years. My first roll in HC-110 was over developed. Using Dilution B (1:31) the Massive Development Chart indicated seven minutes, or about twice as long as the Kodak Data Sheet indicated. I did a roll today and used Dilution E (1:47) for six minutes and it looks about right.

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Hi madNbad,
I was thinking about that this morning...
The tests I did for TX in HC-110, were done with 1+31, which gives an optimal upswept curve for HP5+/overcast, but IMO that curve is not as optimal for tri-x possibly because of its more pronounced contrast: maybe I should give tri-x a new chance in HC-110 1+99 (my sun dilution) for overcast scenes, as at that dilution I imagine development becomes a more compensating one, producing a less upswept curve, at least in theory better for TX.
In that case, as HP5+ requires a third more development time than tri-x, I think I would get nearly perfect negatives cutting back my 10m time for sunny HP5+ to 7:30 for TX.
That I'd do with confidence.
Anyway, I'd like to see the same thing done with D-76 as it would be my first time.

pentaxuser said:

So isn't that the basic formula that your thread seeks? Congrats, you've found it yourself

pentaxuser

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Hi pentaxuser,
Understood joking apart, this thread is about how possible it would be taking a sun development with HC+99, and translating it to get the same tone with a high D-76 dilution.
Yet I think it is possible.
And the other option (using HC-110 for tri-x too) is interesting as well: the dilution thing would explain why opinions are so divided about HC-110 being great/horrible for TX.

Many years ago (1980's) our college 101 photography course used Tri-X and HC110 dil. B (1+31) for 35mm format. The results were very good, but most of the prints were only 8x10. I printed a few of mine up to 16X20, but grain started to become a problem, at least for me. We never tried any dilutions other than B. After the class was over, I used ID11 for almost everything and liked it much better. I just never got used to those very short developing times with HC110 dil.B. I haven't used HC110 since then and probably never will with XtolR and Pyrocat HDC in the cabinet. One thing I might use it for is if I find an old roll of film in an antique folding camera and want to develop it. It works very well for cutting through the fog on old film.

One first question to resolve (Chemists) would be:
If HC-110 dilution B, 1+31, "works like" D-76 1+1, which D-76 dilution "works like" HC-110 1+99 ?
(Not easy, as with 1+99 I use the minimal amount (6ml), while with 1+31 I use nearly twice that amount of developer, 11ml...).

Apparently, Ansel Adams used HC-110 dilution G ( 1:119) for 18 min with Tri-X with minimal agitation ( 15s every 3 min) as a way of bringing out shadows while not blocking highlights. Maybe worth a try?

Craig said:

Apparently, Ansel Adams used HC-110 dilution G ( 1:119) for 18 min with Tri-X with minimal agitation ( 15s every 3 min) as a way of bringing out shadows while not blocking highlights. Maybe worth a try?

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That's often not recommended, as that tri-x and current tri-x have nothing in common.
But I agree that's the type of development I do for sunny HP5+... It's just that I have no more TX for common testing.
If no other forum members expose (and share here) sunny tri-x as generously as it can hold it for diluted D-76 with reduced agitation, I may end up doing it in HC+99 as pentaxuser (and I) said.

I know you're switching to Tri-X from HP5+ (I did, too). But this is just a reference for HP5+ using Adams's HC 110 18 min. semi-stand. Yellow filter on Leica M35mm Lux FLE. Pretty typical

What was your exposure?
Do you have a direct wet print from that frame?
Negative scans have no real tonal meaning.

Juan Valdenebro said:

What was your exposure?
Do you have a direct wet print from that frame?
Negative scans have no real tonal meaning.

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sorry. I don't remember the exposure nor did I wet print it. I don't think I did much to it in post, but that doesn't help you.

bags27 said:

sorry. I don't remember the exposure nor did I wet print it. I don't think I did much to it in post, but that doesn't help you.

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Thanks, but it's not about doing a lot of post or not: a scanner sets new points for black and white no matter if the film was underxposed/overexposed and/or underdeveloped/overdeveloped.
Thanks again.