Tandemfahren
Hello there,
In a tattered little booklet (“Die Ilford Negativtechnik” by Jost Marchesi, 1981), I found the following:
To increase sensitivity by 3 to 4 DIN, it is suggested that the film be soaked for 6 minutes in an “oxidising bath” before development.
This is to be prepared from 5g each of potassium metabisulphite and sodium sulphite sicc.
Apart from the fact that potassium metabisulphite is actually a reducing agent (is that right?), what are we to make of the whole thing?
Before I go and try it out...
Alternatively/in addition, for next time I’d consider pre-exposing the whole roll with a flash (I can only manage this with 35mm; rewinding a 120 roll is beyond my dexterity), if only to slightly soften the gradient with increased development.
The background is a slightly panicked attempt at band photos – found out about the gig too late and then only found two rolls of Delta 3200 in the drawer.
No time, no material to test with. So I guessed at the exposure: face on Zone V at ISO 1600. All f/4, 1/90s. Ahem.
One clip developed in ATM49 1+1 at 25€ has turned out relatively promising, but they could certainly be a bit softer and with more density.
Would another developer (Promicrol, Microphen...) perhaps be even better at utilising the sensitivity? Although ATM49 is already good in that respect.
Grain is fine, but not so washed out.
Am I right in thinking that a higher temperature with ATM49 tends to produce a flatter gradient?
Phew, lots of questions!
If there’s anything worth showing among the remaining 60 shots, I’ll have a go at scanning them. Anyone who hasn’t seen Adam Bomb yet should wait a bit before passing away...
Best regards,
Frank
StefanCaspari
Hello,
In a tattered little booklet (“Die Ilford Negativtechnik” by Jost Marchesi, 1981), I found the following:
To increase sensitivity by 3 to 4 DIN, it is suggested that the film be soaked for 6 minutes in an “oxidising bath” prior to development.
This is to be prepared from 5g each of potassium metabisulphite and sodium sulphite sicc.
Apart from the fact that potassium metabisulphite is actually a reducing agent (correct?), what are we to make of the whole thing?
Before I go and have a go at it...
Alternatively/in addition, for next time I’d consider pre-exposing the whole roll with a flash (I can only manage this with 35mm; rewinding a 120 roll is beyond my dexterity), if only to slightly soften the gradient with increased development.
The background is a slightly panicked attempt at band photos – found out about the gig too late and then only had two rolls of Delta 3200 left in the drawer.
No time, no material to test with. So I guessed at the exposure: face on Zone V at ISO 1600. All f/4, 1/90s. Ahem.
One clip developed in ATM49 1+1 at 25€ has turned out relatively promising, but they could certainly be a bit softer and more dense.
Would another developer (Promicrol, Microphen...) perhaps be even better at utilising the sensitivity? Although ATM49 is already good in that respect.
Grain is fine, but not so washed-out.
Am I right in thinking that a higher temperature with ATM49 tends to produce a flatter gradient?
Phew, lots of questions!
If there’s anything worth showing among the remaining 60 shots, I’ll have a go at scanning them. Anyone who hasn’t seen Adam Bomb yet should hold off on dying for a bit...
Best regards,
Frank
Hello Frank!
The negatives are always ‘struggling’ with these settings – the result will always show that.
I’d give Emofin a go (two-bath process); with a one-step developer, you’ll usually run into gradation issues when increasing the sensitivity.
Best regards: Stefan
Tandemfahren
Hello,
Well, I’ve already had a go at the Emofin. The speed (Zone 1) is a measly 500 ASA with the Delta 3200, and the curve is very S-shaped, which I really don’t like at all.
The results I got were rather off-putting.
Up to now, I’ve always managed to get a nice, straight curve up to Zone X with the ATM49 (APX100 + 400, Foma400), which, with the right exposure, is often more to my liking than uncontrollable crash-landings on the foot or shoulder of an S-curve – a curve I don’t even like when I do manage to hit it.
(That said, some people can of course get great results with it)
As I said, the basic idea is to use pre-exposure and/or chemical pre-treatment to compensate for the loss of gradation caused by the (unfortunately unavoidable) forced development. Even Uncle Ansel described the loss of gradation through pre-exposure.
Franz, how’s it going? Potassium metabisulphite – what do you think?
Regards
Frank
cfb_de
I can't be bothered with that right now. The photo books are still packed away in moving boxes.
Best regards,
Franz
Tandemfahren
"What on earth... I always thought you were a book on photographic chemistry?" – and well...
piu58
Astronomers have been working on what is known as ‘hypersensitisation’ ever since they used film. The film was usually treated in a hydrogen atmosphere at high temperatures. As far as I know, this was only worthwhile for low-sensitivity films; documentary film was particularly popular.
Increasing sensitivity chemically involves mercury. You have to wind the film onto the spiral, break an old thermometer and put a little mercury into the canister. Leave it there for a week. After use, the mercury must be placed under water. You can decant it for next time and dry it with kitchen paper.
StefanCaspari
Astronomers used to experiment with so-called hypersensitisation back when they were still working with film. The film was usually treated in a hydrogen atmosphere at high temperatures. As far as I know, this was only worthwhile for low-sensitivity films; documentary film was particularly popular.
Increasing chemical sensitivity involves mercury. You have to wind the film onto a spiral, break an old thermometer and put a little mercury into the canister. Leave it there for a week. After use, the mercury must be placed under water. You can decant it for next time and dry it with kitchen paper.
Yum!
Have you ever ‘dried’ mercury with kitchen paper?
Perplexed regards from Munich: Stefan
StefanCaspari
Astronomers used to experiment with so-called hypersensitisation back when they were still working with film. The film was usually treated in a hydrogen atmosphere at high temperatures. As far as I know, this was only worthwhile for low-sensitivity films; documentary film was particularly popular.
Increasing sensitivity chemically involves mercury. You have to wind the film onto a spiral, break an old thermometer and put a bit of mercury into the canister. Leave it there for a week. The mercury must be placed under water after use. You can decant it for next time and dry it with kitchen paper.
Once again, seriously:
You can’t possibly be serious!
Mercury is one of the most aggressive and complex elements there is, and on top of that, it’s very, very toxic!!
What’s more, it’s a metal that evaporates at room temperature (which is supposed to be the effect in the developing tank).
Whether this ‘exposure’ to mercury actually works is open to question (without sufficient testing, it’s a bit of a gamble anyway)—
in any case, it’s completely daft to set off such a chemical time bomb just because a ‘colleague’ was disorganised and didn’t have the right materials in stock in the necessary quantities!
Mercury causes cancer, cancer and more cancer, brain damage, damage to genetic material – no roll of film is worth that!
Regards, Stefan
StefanCaspari
Hello Frank!
So as not to just ‘complain’ here, here’s a tip.
Found in ‘Marchesi – Photokollegium Vol. 1, 1981 edition, page 59, section 3.12.1.h): Sensitivity-enhancing surface developers (recipe follows) and a reference to Microphen, Neofin, Baumann Acufine and Paterson Acuspeed.
Furthermore, on the subject of mercury in the same book: page 69, point 3.16 Mercury chloride intensifier
Briefly, the equation: For the oxidation process: Negative silver + mercury chloride + potassium bromide
= silver mercury bromide + potassium chloride
For the reduction process: Silver mercury bromide + sodium sulphite + water
= mercury + silver + sodium sulphate + hydrobromic acid.
As you can see, the mercury intensifier is a highly toxic affair, especially as you aren’t working under a fume hood, and the mercury vapours can escape freely and settle wherever they please – including in your lungs!
If you like, send me your email address and I can send you copies of the recipes and the full text.
Kind regards, Stefan
KlausWehner
Hi Stefan,
I tried chemical latentisation many years ago: no measurable effect! (But it doesn’t do any harm either).
In my opinion, latent pre-exposure would be a bit more promising. The tricky part is getting the dosage right.
The base fog will increase and the contrast will decrease. (You can compensate for this with a forced development). Under no circumstances should you use too much light!
Personally, I don’t consider the Delta 3200 to be a particularly suitable film. I’m currently comparing the Delta 3200 with the Neopan 1600 in my darkroom.
The Neopan has the higher speed and, at the same time, better image quality. The effective speed of the Delta 3200 is between 400 and 800 ASA.
I don’t actually recommend Emofin or A49 because of their problematic ingredients. But if you’ve got A49 to hand anyway, it might be worth a try.
You shouldn’t expect truly optimal results – really, it’s just a matter of damage limitation.
If you’ve got plenty of time, I might be able to (…) test a homemade solution for forced development for you.
Regards
Klaus
Tandemfahren
Hello everyone!
@Stefan+Uwe: Don’t argue. I’m not having any mercury in my house – not in liquid form, not as a salt, not even in writing!
Thanks anyway for the enlightening debate...
@Klaus: I just happened to have the Delta on hand, and now I’ve ordered some more to test it out later so I can lift my little darlings.
Besides, it’s available in 120.
I can confirm your sensitivity measurement (in Emofin, see my second post). Pretty poor.
Your unsuccessful attempts at sensitisation: which film and which formula did you experiment with?
The small piece of film that turned out halfway decent was processed in A49.
A quick note on hypersensitising for the astro folks: ‘Hyping’ with hydrogen doesn’t actually increase the speed. It eliminates the Schwarzschild effect.
In astrophotography, of course, this means vastly reduced exposure times, but it doesn’t help me right now.
Tell me, Klaus, since you so generously (thanks!) offered to test a special process: you aren’t by any chance the very same SW-slide-Wehner whose laboratory exploits lie beyond all our horizons?? Whose reputation echoes across the land like thunder across the prairie?
Since no one seems able to say anything more specific about the exact speed in Microphen, Promicrol and the like, here’s my question from the EP again:
Is it the case that a higher development temperature (25°C) with the A49 flattens the gradient? – with the development time adjusted, of course; not that you should think I’m stupid...
Thanks for now
Frank
KlausWehner
Hi Frank (!)
Apologies for the mix-up with the names!
Frank, you’re flattering me with your praise… But there aren’t that many Klaus Wehners about – and I am indeed the one with the black-and-white slides. (Reverse development according to Wehner)
My attempts at latentisation must have been at least 20 years ago. Unfortunately, I no longer have any records of them either.
Starting formula: 0.5% potassium metabisulphite, 1% sodium sulphite, in distilled water.
(Source: Hans BORTSCH, K.E. DECKART / Mittelformatpraxis / 1982 Verlag Großild-Technik GmbH Munich).
I did vary the starting solution in terms of concentrations.
The film stock tested was primarily HP 5 (but also FP 4).
After that, I looked into latent pre-exposure. The effect is detectable – but it significantly degrades the image quality.
Important! Under no circumstances use too much light!
Thanks and best regards
Klaus
KlausWehner
Hi Frank (!)
Apologies for the mix-up with the names!
Frank, you’re flattering me with your praise… But there aren’t that many Klaus Wehners about – and I am indeed the one with the SW slides. (Reverse development according to Wehner)
My attempts at latentisation must have been at least 20 years ago. Unfortunately, I no longer have any records of them either.
Starting formula: 0.5% potassium metabisulphite, 1% sodium sulphite, in distilled water.
(Source: Hans BORTSCH, K.E. DECKART / Mittelformatpraxis / 1982 Verlag Großild-Technik GmbH Munich).
I did vary the starting solution in terms of concentrations.
The film stock tested was primarily HP 5 (but also FP 4).
After that, I looked into latent pre-exposure. The effect is detectable – but it significantly degrades image quality.
Important! Under no circumstances use too much light!
Thanks and best regards
Klaus
piu58
Mercury is one of the most reactive and complex elements in existence, and on top of that, it’s extremely toxic!!
What’s more, it’s a metal that evaporates at room temperature (which is, of course, what causes the reaction in the developing tank).
Mercury is neither aggressive nor toxic. It is the vapours that are toxic, which is why it should be kept under water.
That is the problem with today’s half-knowledge and ignorance: substances that are easy to handle are demonised, whilst the truly aggressive drain cleaner is right behind the toilet.
StefanCaspari
Mercury is one of the most reactive and complex elements in existence, and on top of that, it’s extremely toxic!!
What’s more, it’s a metal that evaporates at room temperature (which is, of course, what causes the reaction in the developing tank).
Mercury is neither aggressive nor toxic. It is the vapours that are toxic, which is why it should be kept under water.
That is the problem with today’s half-knowledge and ignorance: substances that are easy to handle are demonised, whilst the truly aggressive drain cleaner is right behind the toilet.
Well, hello!
By ‘aggressive’, I didn’t mean the usual aggressiveness in the chemical sense (such as an acid), but rather its tendency to form amalgams (including with silver), as well as its recognised reactivity with aluminium (I believe there are occasionally aluminium containers and objects, as my current half-knowledge suggests).
If you could explain to me how to get the liquid mercury out of the developer tank before the development begins, and ‘submerge’ it without it coming into contact with the air and thus evaporating, or otherwise taking on a life of its own, I’d be grateful....
Incidentally, I share your view on half-knowledge and the like; I don’t know if you’re old enough to judge ‘today’s half-knowledge and ignorance’, but I’m sure you share my opinion on arrogance or know-it-all behaviour!
Warm regards from Munich: Stefan
KlausWehner
Mercury has no place in the environment – nor in the darkroom.
Many mercury compounds are toxic and act as environmental pollutants even in low concentrations.
There are intensive efforts to phase out mercury from the economic cycle (e.g. mercury oxide batteries).
Against this backdrop, I find it counterproductive to downplay the issue.
What has been described as ‘half-knowledge’ is precisely the knowledge that enables conscious and responsible handling.
I can therefore only emphatically reiterate what (almost) everyone here agreed on: mercury and its compounds do not belong in the darkroom!
Regards
Klaus
Tandemfahren
Right then!
I’ve now roughly plotted the response curves for the Delta 3200, using the A49, Promicrol and Microphen, all at 25°.
The times are just educated guesses; only the Promicrol got a bit out of hand.
The speed remained stubbornly at a dreadful 500 – rough estimates, as I said. My densitometer is a cobbled-together Lunasix.
Microphen produces the steepest curve slope. ‘Curve’ isn’t quite the right word; it’s more of a ‘line’. A line of blackening.
I then drowned the last streak in the magic bath from the book. I could have left it out; it made no difference.
What does the lab pro think – pre-soak for longer, or is it all a waste of time?
Thanks and best regards
Frank
KlausWehner
Hi Frank,
You’ve found exactly the results I was expecting:
effective speed for the Delta 3200 at 500 ASA (I think 640 ASA is also possible)
no effect from the latentising bath.
You’ll only achieve a measurable effect with pre-exposure – but even that won’t work miracles. (You can create a ‘qualified fog’ – nothing more).
Extreme developer concentrations might yield a gain of 1, at most 2 DIN – with a significant deterioration in image quality.
With such a tight exposure, the information in the shadow areas is simply missing. What could not be stored on the latent negative due to the insufficient exposure cannot be conjured up retrospectively through chemical tricks either.
What would I do?
Develop the film as standard (possibly with a slightly extended time) using Micophen (or A49).
This way, you will at least achieve the best possible image quality under these circumstances. You won’t be able to recover the missing image information onto your negatives, even with rescue attempts (which always further degrade the image).
If you’re lucky, there will be negatives you can use – and then you’ll at least have a usable image quality.
With all other measures, image quality will always be compromised – without you gaining (much) in return.
Ultimately, when printing, you can achieve almost exactly as much (or as little) as you would with the other measures mentioned – only you have the advantage of having a usable negative.
Thanks to your thorough preparatory work, you now know roughly what to expect. That helps a great deal!
Finally, you still have the option of presenting these ‘difficult’ photos quite boldly as artistic, unique, dramatic and exactly as intended. Many do this (and some actually believe it) and reap admiration and recognition for it!
Either way – I wish you every success! Approach it positively – then something will come of it!
Warm regards
Klaus
Tandemfahren
Hello again,
That’s exactly how I see it now, too. In fact, I’d go so far as to say that the whole concept of ‘push processing’ is nonsense from the outset.
At least as far as SW film is concerned. And as long as the steep gradient doesn’t serve any real purpose, of course.
I just wish I knew what got into Jost Marchesi when he mentioned this method? There’s definitely something behind it, but what and how will probably remain a mystery to me. A shame, learnt nothing again.
See you soon (until the pictures are ready)
Frank
KlausWehner
Hi Frank,
I completely agree!
Pushing can’t actually work. If the film has been underexposed to the point where the details in the shadows are no longer recorded, no amount of pushing can salvage it. It will always just remain black.
In photography, there are a whole host of myths that are passed on without being checked and eventually find their way into specialist books. Then everyone just copies from one another.
Much of it is demonstrably nonsense – yet, undeterred, it takes on a life of its own and is impossible to eradicate...
I determine the working sensitivity of a film by taking practical shots of a Kodak grey scale.
The darkest area must just about be clearly distinguishable from the area in front of it on the negative.
Density measurements are then unnecessary (and often lead to inconsistent results).
The speed determined in this way is very consistent and is only slightly affected by external conditions (such as different developers).
In my opinion, it is the safest, simplest and best way to achieve optimal exposure for a film.
Do get in touch again when you have your results!
Best regards
Kaus
