Effects of increasing Sodium Metaborate in BTTB

They all have more or less the same SBR

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How do you come to this assumption? - I suppose that it is because I have a certain ‘look’ that I like for my exhibition prints and this is perhaps what is fooling you?

Although I do not generally take notes of exposure, with this image:

http://m3.i.pbase.com/o6/45/376345/1/148305013.cO1O4PeG.PraterGarten12012.jpg

I remember the shadow area read 8 on my Weston meter which, when placed on Zone III, gave an exposure of 1/15 @ f16. This led to the white wall falling on Zone X. However, using the two-bath developer, the white wall was controlled and prints as a very light grey with texture with no need to change grades.

In this image:

http://m8.i.pbase.com/o9/45/376345/1/155159818.pt2fbZYI.2013_dsall_graben.jpg

The area under the under the petrol station roof measured 11 on the Weston meter giving an exposure, when 11 was placed on Zone III, of 1/125 @ f16. This led to the white wall falling on Zone VII but can be rendered in the print as much nearer Zone VIII without needing to resort to Grade 5.

So, as you can see, your assumptions about subject brightness range in my photographs are completely wrong.

The only variable in these prints is the sky, and it is all over the place.

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I do not know where you live but the sky in Europe varies a lot throughout the day. In addition, I generally choose how I want my skies to look based on the photograph. I was honestly not aware that there was an ‘official’ tone that skies should have - seems like I have transgressed an unknown ‘rule’.

. . . .and alleged magic tonality.

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I do not recall writing that BTTB developer (or any other developer for that matter) produces ‘magic tonality’ but rather that it delivers results that other posts suggested that it could not. Now in the first example image I would question whether a ‘conventional’ developer could have held this subject brightness without adjusting the development. Given that the second example image could well have been on a roll with a similar image with similar subject brightness range then adjusting development to suit the first image would have negatively impacted on the second one. This is not the case, in my experience, when using a two-bath developer - oh by the way, have you ever actually used a two-bath developer yourself?

Gerald Koch and I rarely see eye-to-eye. Nevertheless, he makes his comments in a cogent manner and states what he believes to be correct information for the benefit of other people on APUG. Gerald’s comments about Sandy King’s article are fair in that his testing methods were not scientifically sound and it lacked the references that one would expect from an article presented as a technically specific revue of a certain methodology. The fact that many people do not adhere to good practice (or worse, actually knowingly produce texts that are wrong, deliberately misleading or comprising entirely of gobbledegook) does not change what one should expect from a serious scientific paper.

Rudeofus you seem to want to rubbish what either Gerald and I have to say. Why one would want to do this is a great puzzle to me. Given that over 1,000 people have viewed this thread and I assume that some of those are either beginners or people seeking to approve the technical aspects of their photography, I do not think your comments are either helpful or particularly appropriate to the aims of APUG - which I believe to be providing information (subject to each contributor’s experience and knowledge) that may be of benefit to other analogue photography enthusiasts.

Bests,

David.
www.dsallen.de

Gerald C Koch said:

I take exception to the following claim in the King article "4.Surface development, which results in higher sharpness."

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I would agree with you... striking this line from the article adds value to it by taking away a conclusion that shouldn't have been drawn.

But I think this enthusiastically-written article can be accepted by our community as presenting some good ideas to think about.

I've been reading many old photography books, and I'm discovering some authors who are so wrong I can barely hold the book open (William Mortensen). One author is only a little wrong on minor details. I am having a very good time reading an enthusiastically-written book by Aaron Sussman, The Amateur Photographer's Handbook. Among his little misunderstandings is that he mentioned the Zone System works to expose middle gray correctly (when we all know the intent is to expose the shadow correctly). But there is something about Aaron Sussman's style that makes the reading fun, even if I find myself disagreeing with some points. I feel that way about Sandy King's writing.

David Allen said:

I remember the shadow area read 8 on my Weston meter which, when placed on Zone III, gave an exposure of 1/15 @ f16. This led to the white wall falling on Zone X. However, using the two-bath developer, the white wall was controlled and prints as a very light grey with texture with no need to change grades.
[...]
The area under the under the petrol station roof measured 11 on the Weston meter giving an exposure, when 11 was placed on Zone III, of 1/125 @ f16. This led to the white wall falling on Zone VII but can be rendered in the print as much nearer Zone VIII without needing to resort to Grade 5.

So, as you can see, your assumptions about subject brightness range in my photographs are completely wrong.

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Are you trying to suggest that BTTB somehow senses "oh, this is a white building, I need to make it print light gray at grade 3" ? Trust me (or trust Michael's test results if you prefer), BTTB can only apply one characteristic curve to whatever you throw at it, and that curve doesn't deviate all that much from what most other developers give you. There is no "autolevels/autocontrast" option in analog photography.

David Allen said:

I do not know where you live but the sky in Europe varies a lot throughout the day. In addition, I generally choose how I want my skies to look based on the photograph. I was honestly not aware that there was an ‘official’ tone that skies should have - seems like I have transgressed an unknown ‘rule’.

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I used the sky as evidence that BTTB does not render every scene the same way. If your skies are all over the place, your buildings would just as well as soon as you move away from sunlit white buildings.

David Allen said:

I do not recall writing that BTTB developer (or any other developer for that matter) produces ‘magic tonality’ but rather that it delivers results that other posts suggested that it could not.Now in the first example image I would question whether a ‘conventional’ developer could have held this subject brightness without adjusting the development. Given that the second example image could well have been on a roll with a similar image with similar subject brightness range then adjusting development to suit the first image would have negatively impacted on the second one.

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My posts say that BTTB can't do what you claim it does, but it can do very well what you show it does, and most other developers can do the same. As I have mentioned before, modern film has incredible dynamic range, and if a developer gives you too much negative contrast for a given SBR, a lower paper grade will most likely save the day.

David Allen said:

Gerald Koch and I rarely see eye-to-eye. Nevertheless, he makes his comments in a cogent manner and states what he believes to be correct information for the benefit of other people on APUG. Gerald’s comments about Sandy King’s article are fair in that his testing methods were not scientifically sound and it lacked the references that one would expect from an article presented as a technically specific revue of a certain methodology. The fact that many people do not adhere to good practice (or worse, actually knowingly produce texts that are wrong, deliberately misleading or comprising entirely of gobbledegook) does not change what one should expect from a serious scientific paper.

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Sandy King, just like Pat Gainer, wrote their articles at a time which I consider the worst possible time in late history for their kind of work. All the major companies had ditched their black&white research efforts by then, most scientific research journals about analog photographic processes ceased publication, there was little money gained by doing this kind of research work. At the same time the internet was in its infancy, patent searches were extremely tedious, resources from foreign countries barely accessible, online purchases a rare option, pH meters and precision scales were out of reach for most amateurs.

It was in these times when Sandy and Pat did their experiments with Pyro/Pyrocat and Ascorbate, and as a benefit to us they freely published and discussed their work for everyone to read. I don't remember reading that they ever claimed their work was scientific research in the classical sense, so let's please cut them some slack.

Are you trying to suggest that BTTB somehow senses "oh, this is a white building, I need to make it print light gray at grade 3" ? Trust me (or trust Michael's test results if you prefer), BTTB can only apply one characteristic curve to whatever you throw at it, and that curve doesn't deviate all that much from what most other developers give you. There is no "autolevels/autocontrast" option in analog photography.

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But as the two examples I gave demonstrate, BTTB developer does in fact work in a similar way to autolevels/autocontrast. The two scenes had very different subject brightness ranges but nevertheless match each other in tonal appearance when exhibited together.

As has been written elsewhere, with two-bath developer the development in more exposed (denser) areas of the negative is of course quicker, but it also stops (or slows down) faster because the reducing agent is more quickly exhausted. Inversely, the development in less exposed areas goes on for a longer period, and these areas gain more density relatively to their exposure. In other words, two-bath developers produce a usable negative regardless whether the photographic scene was of low or high contrast. This is of great use for roll films where there will be very many different types of shots are made on a single roll.

Now whatever characteristic curve is produced for BTTB developer, the fact is that it works as I (and many others) have described.

I used the sky as evidence that BTTB does not render every scene the same way. If your skies are all over the place,

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I still do not get your point. What exactly does “skies are all over the place” mean? - that you do not like how I wish to render skies in my photographs or you believe that there is a standard level of grey to which skies should be rendered or somehow BTTB developer ‘messes up’ the sky level when rendering both shadows and highlights correctly?

Perhaps you could enlighten me by posting a couple of images with the ‘correct’ (not “messed up” or “all over the place”) tone for the sky.

I find it hard to believe that you have actually used BTTB developer given the comments that you make. Sure, many people approaching development from a scientific/technical direction have reported that the characteristic curve of BTTB developer is not dissimilar to many other developers. However, in practical use I have found this not to be the case. I am sure that, if I had used HC110 Dilution B for the first example photograph, I would have needed to reduce the development time to hold the bright highlights (thereby compressing the mid-tones). Likewise, if I had used HC110 Dilution B for the second example photograph, I would have needed to increase the development time to hold the expand the tonal range to render the white wall at Zone VIII where I wanted it.

Bests,

David.
www.dsallen.de

David Allen said:

But as the two examples I gave demonstrate, BTTB developer does in fact work in a similar way to autolevels/autocontrast. The two scenes had very different subject brightness ranges but nevertheless match each other in tonal appearance when exhibited together.

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You argue that you can have multiple contrasts on one roll by changing exposure, because your compensating developer changes contrast with exposure. If you had significant flattening of your curve at higher densities, you'd have very bland highlights, and that's not what I see in your images. Michael's test results also show that there is no significant flattening of the characteristic curve.

David Allen said:

As has been written elsewhere, with two-bath developer the development in more exposed (denser) areas of the negative is of course quicker, but it also stops (or slows down) faster because the reducing agent is more quickly exhausted. Inversely, the development in less exposed areas goes on for a longer period, and these areas gain more density relatively to their exposure. In other words, two-bath developers produce a usable negative regardless whether the photographic scene was of low or high contrast. This is of great use for roll films where there will be very many different types of shots are made on a single roll.

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See Michael's tests. Lots of people wrote lots of things about two bath developers, few made actual tests. Densitometers were not cheap and easy to come by fifty years ago. Fifty years ago emulsions were unhardened and a lot thicker than today's emulsions, and carry over was significantly higher. Observations from back then are often irrelevant with today's materials.

David Allen said:

I still do not get your point. What exactly does “skies are all over the place” mean? - that you do not like how I wish to render skies in my photographs or you believe that there is a standard level of grey to which skies should be rendered or somehow BTTB developer ‘messes up’ the sky level when rendering both shadows and highlights correctly?

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You skies are exactly where they should be, and from an artistic standpoint they look just right in your images. What they do show, though, is that BTTB doesn't put objects into a density range, it puts brightness levels into density ranges. The same applies to foreground shadows, fully lit buildings and all other objects in your images.

But maybe that wasn't your point anyway, I may have misunderstood you. Maybe all you claimed was that with BTTB you can adjust negative contrast by changing EI of your exposure. First of all, this technique costs you multiple stops of speed for high contrast scenes, and secondly there are much better ways to achieve different print contrast.

David Allen said:

However, in practical use I have found this not to be the case. I am sure that, if I had used HC110 Dilution B for the first example photograph, I would have needed to reduce the development time to hold the bright highlights (thereby compressing the mid-tones). Likewise, if I had used HC110 Dilution B for the second example photograph, I would have needed to increase the development time to hold the expand the tonal range to render the white wall at Zone VIII where I wanted it.

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There is no need to extend development time (unless you like big grain), and you'd get poor results with reduced development. Develop normally (i.e. such that you can print average negs at grade 2-3), and use the appropriate paper grade for printing. There is a huge difference between grade 0 and grade 5, use it. When I get around to scanning them, I shall post my set of test prints, where I contact printed a Stouffer wedge at grades 0-5.

Just to suggest how a wide variation of results with two baths is possible, not sure that all is !00% correct. Call the developer DH.
(1) As usual, DH + AgBr -> D and H+ and Br- and Ag.
If the pH is increased (increase of OH-), some H+ is taken up and the reaction will run faster giving more Ag, ie, greater density in a given time.
(2) In 2-bath developers part B the reaction stops when developer diffuses out of the emulsion, but high pH will give greater density in this time.

In bath A , after a very long time, the curve is shaped like that associated with gamma infinity, one would not use this.
At more normal times, in bath B the absorbed developer tends to develop the shadows more as it is used up quickly in the highlight regions.
This would bend the curve downwards compared to that obtained in bath A alone. To maximise the relative effect of the B bath, increase the density it gives by increasing pH, eg by using a lot of metaborate or carbonate.It will increase the contrast near the shadow end of the curve but decrease it near the highlight end, for the same density as obtained with a single bath.

I admit to being an ex user of Thornton's, its hard work 2 baths.

You argue that you can have multiple contrasts on one roll by changing exposure,

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Yes exactly and far better formulated in words than I have achieved so far in this thread.

Lots of people wrote lots of things about two bath developers, few made actual tests. Densitometers were not cheap and easy to come by fifty years ago. Fifty years ago emulsions were unhardened and a lot thicker than today's emulsions, and carry over was significantly higher. Observations from back then are often irrelevant with today's materials.

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I have exclusively used two-bath developers for my own work for the past 12 years. Therefore, my comments relate to current materials. I have always used Delta 400 which demonstrates some effective speed loss when using a two-bath developer. However, students come with a variety of films and, as a generalisation, ‘older’ type films such as FP4, Tri-X, etc demonstrate some slight speed increase (all as expected). Indeed, Tri-X (400) in BTTB developer demonstrates quite a significant speed increase (presumably because of its long toe section). However, I do not like for my own work the more noticeable grain when compared to Delta 400.

Maybe all you claimed was that with BTTB you can adjust negative contrast by changing EI of your exposure.

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Yes again, exactly correct and probably a more clearly formulated text description of how I work with BTTB developer / exposure.

First of all, this technique costs you multiple stops of speed for high contrast scenes, and secondly there are much better ways to achieve different print contrast.

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Yes some scenes require more exposure (resulting in needing to use a slower speed or wider aperture) but this has never caused me any problems. Given that there is a minimum amount of exposure required to place a desired shadow are on Zone III, I am not sure what better ways could be employed to achieve this. If there is insufficient exposure for a given shadow then the only choices in the print are to have it as a dark grey with not detail or print in down to black - neither options being what I want for my images.

When I get around to scanning them, I shall post my set of test prints, where I contact printed a Stouffer wedge at grades 0-5.

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Thanks for the offer but I do not find step wedges very meaningful. When I look at actual images, I can see the level of shadow detail, highlights and, for me very importantly, how the mid-tones look.

Bests,

David.
www.dsallen.de

In my opinion, the question to be asked is: did you achieved a picture in a divided developer that you could'nt have achieved exactly the same way in a "continuous" developer.

As far as I know, the answer is 'no'.

But I agree on the fact that divided developers are much easier to use with 36 pictures of various contrast.

Harold33 said:

In my opinion, the question to be asked is: did you achieved a picture in a divided developer that you could'nt have achieved exactly the same way in a "continuous" developer.

As far as I know, the answer is 'no'.

But I agree on the fact that divided developers are much easier to use with 36 pictures of various contrast.

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When the shadows are adequately exposed then developed for 7-stops and printing is the matter of choosing different graded filters, isn't it?

I still can't get this question out of my mind. Once the development time for 7-stops has been established after testing, why it should be difficult to tame the contrast with single-bath developers like D-76?

Michael R 1974 said:

(...) unless gross differences can be consistently observed and agreed upon by a number of observers in a blind test, it is useless to argue about without microdensitometer traces, MTF plots etc. (...)

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Yes, it's useless for developers of the same family (Adox MQ v. D76 divided or not, for example) but not for all: when I look at my prints, I can see whitout any hesitation if I used ID-3 or Agfa-47.

baachitraka said:

When the shadows are adequately exposed then developed for 7-stops and printing is the matter of choosing different graded filters, isn't it?

I still can't get this question out of my mind. Once the development time for 7-stops has been established after testing, why it should be difficult to tame the contrast with single-bath developers like D-76?

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Hi Baachitraka,

in one way you are quite correct in that, if you have adequately exposed for the shadow areas and you have tested to fix your processing time (irrespective of which developer you choose to use) so that bright highlights are rendered on Zone VIII (bright highlight with a trace of detail), then provided that you are photographing a scene that has a 7 stop brightness range you will get a perfect negative. However, the problem lies in the fact that you have tested for a 7 stop brightness range but your subject subject may not have a 7 stop brightness range. Now as you state above, this will not be a huge problem with a certain degree of subject variation (provided that you have adequately exposed for the shadows) because you can adjust the print by using the appropriate contrast grade. There are many photographers who work in this manner and produce very fine results.

When a student comes to me and wants to use a particular developer, we run a series of tests to identify personal EI (using the black test print approach in the darkroom) and then continue to do a Zone VIII test to determine correct development time. This is essentially what you are saying. I explain to them that the critical factor for fine prints is adequate exposure of the shadow areas as a certain degree of contrast control is available through choice of paper grade.

I also point out to them that this tested approach will be adequate for a reasonably broad range of subjects but that there subjects/situations where they will encounter difficulties such as:

• A very high subject brightness range (such as the interior of a church with large windows or city night-scapes where light sources are included within the image) that may well cause problems because giving adequate exposure for the shadows will force you brightest highlights so far up the scale that they will completely b-up and can only be rendered as pure white on the print.
• A very low subject brightness range (such as a rather monotone subject matter on a dull overcast day) that may well cause problems because giving adequate exposure for the shadows produces a negative so low in inherent contrast that, even at Grade 5, you can’t get a fine print with a full tonal range.

None of this would be a problem if using either sheet film or multiple backs on a Hasselblad, Bronica, etc because you can adjust the development time (pre-tested of course) to match the subject brightness range. With roll film in a camera without interchangeable backs this is rather more problematic.

Where, in my experience, the use of two-bath developers come in to their own is that they - in practical use - control a much broader range of subject brightnesses (assuming you have tested them for correct processing time, agitation and temperature) and have the practical result of producing negatives with a similar range of tones over this range of subject brightnesses. In the examples in my earlier post, the one with the dark shaded area at the bottom with the white wall (in full sunlight) above had a very wide subject brightness range and the other one, with the petrol station in the foreground, white building in week sunlight to the top right and generally cloudy sky had a less than ’normal’ subject brightness range. Now this second one required (counter-intuitively) less exposure for the shadows and the first example required much more exposure to adequately capture the shadows. These were both printed at the same time in preparation for an exhibition. Both required very similar exposures and were printed on the same grade. This despite the one with a reduced subject brightness range (which normal wisdom would suggest that it should have required a higher grade) and the other with an extended subject brightness range (which normal wisdom would suggest that it should have required a higher grade).

Now, I know that photographic theory says that this can’t be the case but my experience is that is exactly what happens.

In your opening post to this thread, you asked about the effect of increasing the amount of Sodium Metaborate in bath B. The standard amount is 12g and the alternative version is 20g (assuming you keep all other variables - time, agitation and temperature) constant. The 20g version of Bath B can be useful but not in the sense of how Thornton described it as a true +1 stop expansion (which can be much better achieved by selenium toning the negative). It is much more of a specialised response to a rarely occurring subject matter situation. If I photograph something that has dark shadows and bright highlights but also a significant part of the scene is relatively lacking in mid-tone separation then I use, very very rarely, the alternative (20g) version of Bath B. This has a significant effect on expanding the mid-tones of a scene that was significantly lacking such a mid-tone separation. The best example of such a subject would be typical old buildings in Berlin after the fall of the wall. Many of the facades were a kind of uniform grey (the results of years of neglect, brown coal, smoke damage arising from the war time bombing, the cheap plaster used at the turn of the century, etc) that reproduced as a pretty uniform, and to me boring, mush of mid-tones.

Bests,

David.
www.dsallen.de

Something that has just occurred to me is that Thornton recommended ‘Try about four minutes in each at about 21°C for roll film’ and suggested processing ‘Bath A with agitation every half or full minute -it’s not critical and Bath B, after a quick rap of the tank on a hard surface to dislodge any airbells, let the tank stand still with no agitation for three minutes or so when all development has ceased. Note, though, that while no agitation is ideal, and usually works well for unsprocketed roll film (120/220), there can be streamers from 35mm sprocket holes’.

His prints and illustrations in his books had a typical ‘gentle’ tonal range from deep blacks to bright highlights. I prefer my images to have more apparent visual contrast (but still retaining detailed blacks and highlights).

My testing led me to a development regime of:

• 20˚C for all stages of the processing sequence.
• 5 minutes in Bath A with 4 gentle inversions in the first 30 seconds followed by 1 gentle inversion every subsequent 30 seconds always followed by a quick rap of the tank on a hard surface to dislodge any airbells.
• 5 minutes in Bath B with 4 gentle inversions in the first 30 seconds followed by 1 gentle inversion every subsequent 30 seconds always followed by a quick rap of the tank on a hard surface to dislodge any airbells.

So a question to the more scientifically minded here, could the variations that I introduced (i.e my times, temperature and agitation) be the reason that I seem to achieve a compensating effect for both higher than and lower than ‘normal’ subject brightness ranges? If so, what would be the photographic mechanics of this?

Bests,

David.
www.dsallen.de

I will a test with scenes of various SBR both indoor(direct and indirect flash) and outdoor giving preference to shadows and see how it goes with BTTB and printing.

Me personally want to get over from this confusion...

Michael R 1974 said:

In reference to post #69, you're saying relative to 12g/l, a second bath with a concentration of 20g/l compresses total contrast while expanding mid-tone contrast, but that is not the shape of curve these developers produce.

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No Michael, Thornton suggested that raising Sodium Metaborate from 12g/l to 20g/l for Bath B would deliver the equivalent of N+ development (here we have to also bear in mind my comments in post #70 that highlighted my particular processing regime in comparison to Thornton's own recommendations). However, when I tested this (a long time ago now I have to admit) I found that it did not deliver a N+ development effect in any way that one would understand if comparing it to, say a 10-20% increase in development time using a 'standard' single bath developer such as HC110 Dilution B, D-76, etc.

What I did find was somewhat different. This was that, even with 20g/l of Sodium Metaborate, the Part B developer delivered a very similar result to the results of the 12g/l version of Bath B in terms of tonal control of the shadows and highlights BUT with one important exception, it appeared to expand the tonality of the mid-tones (too much for my liking for everyday use). I then did a test roll photographing exclusively the dull grey facades as mentioned in the last paragraph of my post #69. For this particular subject matter it proved to be ideal and I have since kept a bottle of part B with 20g/l should I ever need it. However, I should point out that I have used it for less than 1% of all the images that I have made.

Bests,

David.
www.dsallen.de

What I did find was somewhat different. This was that, even with 20g/l of Sodium Metaborate, the Part B developer delivered a very similar result to the results of the 12g/l version of Bath B

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As would be expected. Even if you increase the amount of metaborate to 24 g/l in bath B this would only increase the pH by 0.3 units. Far less than what Thorton may have anticipated. This is because pH is measured on a logarithmic scale. The log10 (2) = 0.3. Even changing to another alkali may not have a dramatic effect.

Gerald C Koch said:

As would be expected. Even if you increase the amount of metaborate to 24 g/l in bath B this would only increase the pH by 0.3 units. Far less than what Thorton may have anticipated. This is because pH is measured on a logarithmic scale. The log10 (2) = 0.3. Even changing to another alkali may not have a dramatic effect.

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BTTB changed from the Borax of Stoeckler to Metaborate, that would be about 0.9 pH units.Changing to carbonate could go up about another 1.4 units.It is used in Emofin.

Alan Johnson said:

BTTB changed from the Borax of Stoeckler to Metaborate, that would be about 0.9 pH units.Changing to carbonate could go up about another 1.4 units.It is used in Emofin.

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All this changing of alkalis assumes a predicatble relationship between pH and negative contrast. This is why I used the words "may" and "dramatic" in my post. In addition the pH of bath B is not important it is the pH in the emulsion itself that matters. Any pH comparisons must be done on a molar basis. Most of the data I have come across lists pH values on the basis of percent solutions. It all goes back to someone taking the considerable time and effort to completely document this developer. Until someone does this arguing about it is futile.

Michael, David Allen reported in this thread, that he had very different effects with BTTB depending on which film was used. Is there a chance that your test results don't translate directly into David's images? Obviously, if this is the case, we have yet less reason to blindly apply historical reports to our modern materials.

Everyone seems intent on proving that David's use of BTTB is somehow incorrect, or doesn't align with "photographic theory" when the reality is, all you have to do is look at the photographs he produced. Yes, they are very fine photographs, well seen, well executed, beautifully printed. End of story.

One can have all of the BTZS microscopic depth of knowledge on SBRs, dev times, lens flare and all the blahblahblah and make nothing pictures that no one would waste five seconds to view. It's like the guy who gets the 8x10, the lens, the PYRO, the amazing, top of the line dark cloth, goes to Carmel and can't figure out why his pictures don't look like Edward Weston's. It's like, duh, because you're NOT Edward Weston.

There are a lot of musicians who can find the keys but just can't find the feel. And then you get a self taught pianist like Errol Garner who doesn't know dick about the "theory," but man he's got the feel.

Diane Arbus shot 7000 rolls of film and an assistant developed most of it. Michael Kenna doesn't develop his own film, in fact, he shoots whatever film he can get in whatever country he happens to be visiting, and yet somehow his photos all look like Michael Kenna photographs.

Over the last five years I've used Diafine, BTTB, D76 and XTOL, sometime straight, sometimes diluted 1:1, or 1:2, or 1:3, on Kodak TMX, TMY, TRIX, Ilford FP4, HP5, Fuji Acros, etc. And for some reason they all look like my photographs.

Wherever you go, there you are.

The argument is not about using BTTB, although that could also be done, but rather the rational/chemistry behind its use. Many years ago either Modern Photography or Popular Photography performed an experiment. They had people pick chemicals at random from a list of developer constituents. In most cases the mixtures did develop film. Did they do a good job? It was a mixed bag.

There is no doubt that David Allen has borne the brunt of personal biases against Thornton and his two bath variant under the guise of science. We need more photographers of his caliber sharing in this forum since he is very experienced in using this formula. Parker is spot on for infering that aesthetic inclination dictates technical choices.

Nobody here claimed that BTTB is a bad developer or that David Allen shouldn't use it. What was claimed here repeatedly, and with data to back up the claims, was that there is nothing special or unique about BTTB. With David's photographic vision (which was uncontested here), any film developer could have been used with similar end results.

While it is commonly accepted that being good at engineering doesn't automatically make one an expert of everything else (including art), we might as well accept that great artists are not necessarily good engineers.

To my eye, Thorntons two bath appears to give better local or micro contrast than d76 1:1.

My intention is to learn what I am using and understand its variations and effects.

If we have one curve to show its effects either on mid-tones or on high-lights then it may easy to learn for me but then I can also develop a roll and see its effects.

el wacho said:

To my eye, Thorntons two bath appears to give better local or micro contrast than d76 1:1.

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Unfortunately the human eye is a very poor scientific instrument.