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D76 vs Thornton's 2 Bath HD developer, Ilford Delta 100 in 4x5

Kino

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I typically take 2 shots of any subject to experiment with various development times. I was satisfied with my initial D76 1:1 @ 20c/68f for 6 minutes, so I neglected the 2nd negative until I decided to try Thornton’s 2 Bath HD developer just to see how it would handle the same exposure.

Shot #1 D76



Now, these are scans and not matched the best in curve placement, but good enough to see the differences between the developers.

In the 2 bath, I gave baths A&B equal time at 4:30 @ 20c/68f with a water stop and TF5 fix for 4 minutes.

Shot #2 Thornton's



Since I print with a condenser enlarger, the Thornton’s neg might be easier to print closer to grade 2 than the D76 negative, which in my experience, must be printed at 1 or 1.5; maybe even lower than that.
 
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Wonder how the negative in D76 would print split grade. Somewhat surprised that Thorton's did not separate the clouds more, , was under the impression that it was highly compensating. Nice shot though.
 
I do see a slight difference when I switch back and forth between the two. I see it in the contrast of the belfry shutters and the shadows under the shrubs, but both pictures are very, very close for sure.
 
Paul Howell said:
Somewhat surprised that Thorton's did not separate the clouds more, , was under the impression that it was highly compensating.
Click to expand...

Quite the opposite, not surprising. Compensating means decreasing contrast in the highlights.

Sure, a compensating developer avoids the highlights recording as too high densities, but that is achieved by a decreased slope. Example from the datasheet of APX100 (original)
 
The rationale of a 2-bath developer is to compress the tonality of the image. The benefit of this is supposed to be that it makes the negative 'easier to print' - if it works (IF), everything fits more neatly in the tonal scale of the paper. What's left unmentioned much of the time is what this means for tonality, especially at the higher end of the tonal range.
 
For me, BT2B has several appealing characteristics, including economy, self-sufficiency, keeping properties, and making the best of a variety of shots in different light conditions. Ease of printing is one other attraction, but I sure do appreciate not having to burn in highlights individually! This is a scan from the 35mm negative, but the detail in both the sunlit tent and the tent interior is complete in a straight print on G2.

Here's another example (this is my 'Walk to Paradise Garden'!)

There's one more, fully contre-jour, example that I posted recently in another thread.

I use only BT2B now, with various film types, and for the most part I am happy with the tonality I get. I've seen other comparisons here, including curves that seem to belie the whole compensation thing, but honestly I see no downside compared with other developers. Could I achieve the same or better results with other developers? I honestly don't know. From experience with my older negatives, I believe it would involve a lot more fussing over the print.
 
This type of divided development tends to straighten a film’s characteristic curve somewhat.

A minor complaint but this shouldn’t be called “Barry Thornton’s” anything. It is only trivially different than Adams’s divided D-23 process. It’s not meaningfully different than Stoeckler etc. either.
 

The formula was named thusly.
 

When you print with a condenser enlarger, that is a plus, not a minus to me.
 
Kino said:
When you print with a condenser enlarger, that is a plus, not a minus to me.
Click to expand...

This is the issue I refer to in #7 and I think the root cause of the problem is that people easily conflate "density" and "contrast". It's nice if you're printing that the highest values have densities that aren't too ridiculously high. But the question is whether there will still be sufficient gradation to allow for textures to print well. I think this what @bernard_L is referring to.
I personally think there's a difference between an easy print and a pleasing print. Of course, ideally, you get both.
 
Koraks,
I agree and would rather "burn" my highest values in the scene to get some texture (clouds mainly) than try to compress things down so the clouds printed themselves. Compressing mid-tones in a print is a depressing print to me. Of course, that's just me.
 
Then we agree to disagree.
 
Kino said:
Then we agree to disagree.
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Kino,
I agree with you in that the two bath developers do help when it comes to printing with a condenser light source. They even help tame high contrast copy films and help allow a somewhat" normal print. My problem is with mid-tones being compressed so as not to show good separation of tones. Any way I can stay away from compressed mid-tones I'll use.
 
I am getting confused. @koraks questions what a 2-bath developer does for tonality, especially why one would wish to compress the highlights. @John Wiegerink is concerned that it over-compresses mid-tones. @bernard_L posted an S-curve curve showing very pronounced compression of both shadows and highlights in an un-named developer (also un-named in the datasheet cited), while @Milpool says that developers of this kind tend to straighten out the characteristic curve. A while back, someone posted a test curve here on Photrio that appeared to show no highlight compensation of FP4+ (I think) in BT2B (but regrettably I can't find it now).
[EDIT: Ah, it was this other thread, and the poster was @Milpool]

How are all these notions compatible? What is the truth of the matter?
 
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snusmumriken said:
How are all these notions compatible? What is the truth of the matter?
Click to expand...
Generally a lack of any objective testing or poor/absent control of critical parameters, and a high reliance on assumptions and guesswork, allowing anyone to give their own spin to the discussion. If you look at how I formulated #7, you may notice I specifically allowed for a decent degree of uncertainty. You now understand why...

snusmumriken said:
a test curve here on Photrio that appeared to show no highlight compensation of FP4+
Click to expand...
There's a lot to be said about that as well; you may notice my somewhat skeptical response w.r.t. the alleged benefit of a 2-bath process there.

I don't doubt different developers and development schemes yield different curve shapes in different films. The question is - which combination are we looking at and how does it really perform? In 95% of the time we discuss 'compensating' developers, we all sort of agree to assume the effect is there. How valid is that assumption?
 

My concern about compressed mid-tones is not really about BTTB or two-bath developers, but more about messing around with dilutions and developing times with other one-shot type developers.
 
Unless I'm mistaken I think the curve bernard_L posted is probably somewhat "native" to that film rather than the result of a compensating developer. It does however illustrate the general sort of shape one is usually aiming for with a compensating developer (if the film doesn't already do it).

The various two-solution processes I tried didn't seem to do that, and instead had more or less the opposite effect, so I would not characterize them as compensating.

It's not a type of development I use so I don't have an ax to grind either way, but if it helps at all the results I got are not totally unique - I recall an article Sandy King wrote in View Camera magazine about a few of his own experiments with divided and/or two-solution development and he found the same sort of "curve-straightening" effect and that you could develop to a somewhat lower than normal overall gradient with a little less toe and/or loss of emulsion speed.

Whether or not this is desirable depends, but usually you're trading one problem for another when trying to compress a large scene luminance range so either way you're going to have to work under the enlarger. Watch out for uniformity issues with this type of process.

Image structure is a possible difference. It seems reasonable to expect a grainier negative versus using the D-23-type metol-sulfite developer normally, but who knows. I've read claims of enhanced edge effects if that is something you want, but again who knows.



 

Doesn't Ilford say 11 mins for D100 at 1+1 @20C from what I have found out? So I was a little surprised at how good a negative that 6 mins or nearly 50% less development produces, based on your pic. Makes me wonder how flexible a manufactured recommended time is, to put it mildly

pentaxuser
 

Through personal testing, I have found on very bright, high contrast scenes that 6 minutes in D76 @ 1:1 and 20C/60F works well when printing with my Beseler condenser enlarger; that's all I can tell you.

Unless my Pentax spot meter is totally whacked, and it doesn't appear to be, I don't know what to tell you.

This was more of a "I found this result interesting" rather than some manifesto on 2 bath development.

Of course, those who see dragons everywhere, wave their sword regardless.
 
Thanks I wasn't expecting you to tell me anything. If anything, I was really stating that in certain circumstances such as you describe above, the appropriate time for development can vary from Ilford's time more than most might believe possible

I suppose what it confirms for me is that whenever we collectively try to solve a user's problem we should not set as much store as we seem to in deviations from temperature or makers' recommended time being the likely reason for the said user's problem

pentaxuser
 
When I first saw Milpool’s straight, linear divided-development curves, I thought: ‘Great. This is what I think I want!’

I read about how testers do not like the slow toe on Tri-X, as it doesn’t give them adequate separation in the shadows.

At the same time, it seems that there is the expectation that a compensating developer will deliver an even slower shoulder. Stand development is seen to deliver a high degree of compensation.

In one of his very informative videos (on Youtube), Analogue Andy created a curve for stand development in a Pyro developer. The curve was described as similar to wet spaghetti thrown against the fridge. This curve is not at all linear, and in the high values it shows the totally opposite of a shoulder. You can probably fit this part of the curve with an exponentially increasing curve.

(101) Pyrocat HD: Edge Effects Via Stand & Semi-Stand Development - YouTube at 1:08 into the video, he looks at the curves.

From a curves-viewpoint, it is not what I expected, but maybe my understanding is limited. It seems that only the mid-tones are compressed. In any case, I wish that I had seen Andy’s curves before trying stand development. His video also demonstrates key points regarding the frequency of agitation. Very informative.

I assume that users are happy with the result of stand development and the associated shoulder/highlights representation. If Andy’s curve is anything near usual for stand development, I would conclude that the straight line divided-development curve also would be acceptable from a high-lights viewpoint.

Currently, I am thinking that I want my developer to yield a long straight, linear curve without too much contrast. Then, for a particular film, I could use only one EI and one development process. For the contrasty scenes, exposure could be placed on Zone VIII and for the rest of the scenes Zone III would be used.

Maybe it would be similar to using Kodachrome 200 (long time ago) or a digital camera at ISO 200, converted to monochrome afterwards. I don’t know about the linearity of Kodachrome, but I think of the digital sensor as having very linear curves in use.

Looking at the various recipes (Stoeckler, D-23, BT2B), I agree with Milpool that they are all very similar. I have been thinking of using bath A at 1:1 (with the same agitation!) to get longer, more controllable development times. Or instead maybe adding a small amount of Potassium Bromide.

I have unsystematically been using the higher definition Kates version with Tri-X and HP5+ and I have not noticed any issues regarding uniformity, but would like to learn more about this.

It seems that there are a number of old threads about Divided-Development that I need to read.
 
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