Effects of increasing Sodium Metaborate in BTTB

[Gerald C Koch]

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.

Ditto

 

[Rudeofus]

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.

And that roll of film, filled with subject matter you care about, will ultimately decide whether a process works for you or not. Engineers use Stouffer wedges, characteristic curves, MTF charts and RMS grain measurements, because they need quantifiable numbers in order to optimize a photographic product, because the human eye is so easily deceived, and because film "sees" so much differently than our eyes. It took considerable research by the major film makers to determine, how "looks good" can be correlated with measurable image characteristics.

@el wacho: two bath developers are often associated with higher sharpness, but so are Ascorbate developers like Xtol. And again, if you can fully exploit a film's speed, you can suddenly use a slower, more fine grained film, which should have more effect.

 

[el wacho]

Unfortunately the human eye is a very poor scientific instrument.

no sane photographer would live artistically with the doubt you propose, that of ignoring one's eyes in favor of data.

i'm curious, what scientific testing is available for the measurement of local or micro contrast (apart from the traditional 'visual examination') ?

 

[el wacho]

And that roll of film, filled with subject matter you care about, will ultimately decide whether a process works for you or not. Engineers use Stouffer wedges, characteristic curves, MTF charts and RMS grain measurements, because they need quantifiable numbers in order to optimize a photographic product, because the human eye is so easily deceived, and because film "sees" so much differently than our eyes. It took considerable research by the major film makers to determine, how "looks good" can be correlated with measurable image characteristics.

@el wacho: two bath developers are often associated with higher sharpness, but so are Ascorbate developers like Xtol. And again, if you can fully exploit a film's speed, you can suddenly use a slower, more fine grained film, which should have more effect.

To my understanding, not all two bath developers are alike. metol-only two bath developers appear to be sharper than MQ two bath developers ( and other developer agent paired for superadditivity, such as ascorbate acid and phenidone ) due to the edge effects metol-only developers are well known to produce. Having compared the two types myself, i have settled on the metol only variant. i strongly suggest other photographers do their own testing and visually evaluate accordingly.

 

[Gerald C Koch]

no sane photographer would live artistically with the doubt you propose, that of ignoring one's eyes in favor of data.

i'm curious, what scientific testing is available for the measurement of local or micro contrast (apart from the traditional 'visual examination') ?

RMS (Root Mean Square) granularity. At one time Kodak published values for all their films. Lots of information online. http://videopreservation.conservation-us.org/library/film_grain_resolution_and_perception_v24.pdf

 

[David Allen]

First of all I would like to apologise for the length of this (and indeed other) posts but this stems from my belief that APUG provides an important platform for sharing knowledge about analogue photography and, for which we all have a vested interest, in keeping the practice alive so that we can all benefit from the continuing availability of the materials that we need to continue working in such a rewarding medium. After all, we all have limited time so let us make the experience of participating in APUG, and what we can all learn together, a worthwhile experience.

Dear ParkerSmithPhoto,

I am very flattered about your kind words relating to my photography. I think your comments also are particularly relevant to the motivations of everyone on APUG and what they are seeking to achieve. More on this later in this post.

Likewise el wacko, and I do agree with your statement that ‘that aesthetic inclination dictates technical choices’.

I would like to state that I value the work of people who are concerned with photographic science. Indeed, without such people we would not have seen the very valuable advances in the films and developers that are now available to us. Michael and Gerald seem to me to want to make positive contributions to this site through sharing their knowledge of the mechanics and rationale of how things work. All of us can learn from their input because they are trying to ensure that ‘bad science’ is not propagated. This to me is a valid and welcome form of contribution to such a site as APUG.

However, there is a difference between how things technically work and how empirical results can influence the choices that we all make. Sometimes, I feel that the desire for precise technical description, analysis and adherence to strict scientific evaluation gets in the way of using a particular approach that, whether correctly formulated or not, delivers results. After all, Adams, Picker, White, etc have all written advice that is ‘technically’ wrong but, if you follow their (possibly) flawed advice you WILL be able to produce images that are of a fine quality (let us leave out at this stage whether people following this advice have an ‘eye’ for a good image.

If we consider Michael’s comment that ‘As for the referenced photographic examples, from a technical perspective they don't show me anything that could not have been done with any general purpose developer’. I am sure that what he means is that from his tests and resulting characteristic curves (and related variables that he has tested) nothing demonstrates to him (in a scientific manner) the results that I have described. Nevertheless, unless he was by my side, as I made each image, and could test the variables that I had to deal with, such a a comment is equally unscientific because he does not know the subject values that I was presented with and how my choices affected the final result.

Equally, whilst you can’t argue against the scientific basis of Gerald’s comment that ‘Unfortunately the human eye is a very poor scientific instrument’ it is, after all, the primary tool with which we judge both our, and others’, results.

Likewise, Michael’s comment that ‘the original question concerned alterations to the concentration of sodium metaborate in bath B to control contrast. Theoretically the reasoning is unsound, and I have performed experiments which showed it is not an effective control for contrast. Since bath A is a fully functioning developer, you control contrast primarily by altering time/temp/agitation in bath A. In addition, this type of process does not appear to expand mid-tone contrast. On the contrary, it results in a straighter characteristic curve’, I would argue that the practical results that I have described (not in terms of contrast control but rather in tonal description) show that a change in Bath B does not give (as Thornton stated) a N+ result BUT it does give a useful result, in specific circumstances, to the appearance of mid-tones.

I am all for eliminated the bad science that is out their and equally the bad advice. For example, the ‘guru’ Victor Blackman (I think he was called) for many years at Amateur Photographer magazine in the UK stated that over exposure increases grain. Well I tested this empirically and it is not true. When you think about it logically, it just can’t be true because the highlights on any negative will be massively more exposed than the shadows but the highlights are not more grainy than the shadows - indeed the area that always demonstrates the most grain are the uniform mid-tones. Equally, for all his thoroughness working for the UK's British Journal of Photography doing scientific reviews of new equipment, Geoffrey Crawley always missed the differentiating point between technical testing and in practice use. This was the reason that, after years and years of working with almost no money documenting the life on Dartmoor, when James Ravilious had finally the means to buy a new lens and bought the lens described by Crawley and was very unhappy with the result. He then approached my father to help him sort out a very pressing problem - he was not getting the tonality that he wanted with the new lens. The solution that my father found was very simple, what James sought tonally in his images was the results that could only be delivered by combining an 'older' approach to exposure and developing together with the particular qualities of the lenses made by Leitz in the late (era M3) 1950's. Moving (accordingly to the technically rigorous test of Crawley) backwards from this most modern of lens design to an older design of lens (and it's associated tonal and drawing qualities) solved all of James' problems.

So finally (or probably you are all saying ‘at long last’) back to my comment at the beginning to ParkerSmithPhoto’s more general comments. Whilst I believe that all threads on APUG have validity (even though I am not personaly interested in the ‘compare a Hasselblad to a Bronica’ or ‘What's your latest new old camera ?’) I do feel what is lacking (or perhaps what I really mean is in the number and quality of responses) is the kind of threads that ask “what do you think about photographer A’s work’, which photographer's work do you like and why, what do you think about photography book X’, here is what I do what do you think about my work or, in the context of this current thread, this is what I do and here are my working methods and the results’.

Bests,

David.
www.dsallen.de

 

[Harold33]

Unfortunately the human eye is a very poor scientific instrument.

Since we have nothing else to look at pictures, this point of view can't be neglected.

Human perception is very complex. The more I study photography, the more I understand that some critical properties of pictures are impossible to translate in terms of quantification. The problem is the same with sound. In linguistics, we have plethora of data about phonetics but nobody can explain scientifically why we are able to recognize the voice of a friend after two syllabes, even through the filter of a bad telephone.

 

[el wacho]

"Local" contrast is basic sensitometry/densitometry. Micro-contrast (ie edge effects) requires a microdensitometer and fairly sophisticated exposure equipment.

Ah, so microdensitometry is the issue...

so i've made a qualitative evaluation between Thornton's and D76 1:1, finding Thornton's to be better.

just curious, does anyone have the scientific data to prove otherwise?

the film i'm using is Fomapan 100.


ps Michael, my remarks were never directed at you. İ always found your advice to be sincere attempts to answer the op's questions and not veiled attempts to dissuade in the usage of Thornton's two bath.

 

[Chris Livsey]

For example, the ‘guru’ Victor Blackman (I think he was called) for many years at Amateur Photographer magazine in the UK stated that over exposure increases grain.
www.dsallen.de

David, I have no doubt your memory is correct but in his book "My Way With a Camera" 1974 Focal Press Blackman did not repeat that statement. He was probably, at that time, the epitome of a "practical" photographer and his comments would have been based solely on the unreliable eye. I find the worst statements are those made from those with that dangerous small piece of science and the absolute certainty that their conclusions are correct even if no one else can replicate the results.

 

[Gerald C Koch]

I seriously doubt that very much described in 1974 can be considered definitive. Our knowledge of the photographic processed has changed so dramatically in the past 40 years.

In addition to the human eye having its faults being a simple lens with not very good resolution, the human mind tends to see what it wants to see. This is the reason why double-blind tests are performed.

http://en.wikipedia.org/wiki/Blind_experiment#Double-blind_trials

I have lost count as to the number of times someone has posted examples on APUG and have been unable to decern any difference in the examples.