MirkoBoeddecker
This popped up on the forum today:
"After a test development had already failed about six months ago, I asked on your internet forum what might have caused it. Unfortunately, the development instructions provided are completely inadequate, given the complexity involved! Fortunately, I found out what I’d got fundamentally wrong on my first attempt.
1. I prepared the Bleach bath too early (it apparently decomposes within a few minutes!).
2. I used an insufficient amount of light for the reversal.
I addressed all these factors during the second test development by taking the following measures:
1. I added potassium permanganate to the Bleach bath approx. 2 mins before use (poured it through the open neck of the laboratory bottle into the B1 solution previously prepared with water and resealed the bottle immediately); the potassium permanganate mixed in with relatively little shaking of the bottle.
2. I carried out the reversal using a 500 W halogen lamp; I also used a Lomo developing tank, which allows for far better contact with the solutions than my previous developing tank – in which the film was wound back and forth through the solutions – as well as equally good access for the light (from a distance of approx. 20 cm, as recommended)
The result is dreadful! Just like the first time, the film hasn’t been reversed – despite the ample light from the 500 W halogen lamp! What’s more, the entire film is practically pitch black. On the emulsion side, you can just about make out the images.
As I followed all the instructions to the letter and prepared the solutions very shortly before use (approx. 30 mins before development began, except for the Bleach bath, see above), I must now assume that the development kit itself is faulty. I cannot judge whether the substances supplied are incorrect or the bottle labels have been mixed up. Storage since I received the delivery should be considered flawless (stored in the box in the cellar at approx. 15–18 degrees).
Incidentally, I have many years of experience in a photo lab. Even though I have not developed slide film before, it should be perfectly possible for me to do this myself if I have the necessary information."
Are there any similar cases? Does anyone have any advice for this customer?
I would like to send an email to Foma suggesting improvements to the instructions.
Best regards,
Mirko
SamuliSchielke
If the film is only partially reversed, it looks patchy – negative in some places, positive in others – and generally dreadful. Philipp and I had no trouble reversing the film, at least partially, even though the potassium permanganate had been left open for a while. We did have other problems, but that’s another story... If you expose for too short a time, it turns out rather pale rather than black. Or what do you think, having just spent a weekend trying it out?
In any case, the instructions for the reversal process could be a bit more detailed.
Samuli
RomanJRohleder
Mirko,
"1. Prepared the Bleach bath too early (apparently it breaks down within a few minutes!)."
Correct. And please, please, please prepare it with distilled water and filter it thoroughly immediately before use.
"2. Used an insufficient amount of light for the reversal."
No. A 500W halogen lamp is more than enough; at Michael’s we used 150W, in Steinkimmen – if I recall correctly – 40 or 60W filament bulbs (Philipp?) for the reversal; in Buchenau there were attempts using daylight and an overhead projector – with the latter we should have removed the Fresnel screen, otherwise... no problems.
"1. I added potassium permanganate to the Bleach bath approx. 2 mins before use (poured it through the open neck of the laboratory bottle into the B1 solution previously prepared with water and resealed the bottle immediately); "
Too late. Incidentally, the data sheet still hasn’t been corrected; You did send us a Fomakit as sponsorship material; in German, they’re still singing the old tune: “Part B1: add sulphuric acid, then water”. Outrageous, to quote the old school saying.
“The potassium permanganate mixed in with relatively little shaking of the bottle.”
That may be misleading. I usually prepare the stuff 30 minutes before use; when filtering it 5 minutes before use, there are still small red lumps in the bottle.
“The result is dreadful! Just like the first time, the film hasn’t been reversed – despite the ample light from the 500 W halogen lamp! What’s more, the whole film is pretty much pitch black.”
If it’s pitch black, the light was ample.
Since I followed all the instructions to the letter and prepared the solutions very shortly before use (approx. 30 mins before development began, except for the Bleach bath, see above), I must now assume that the development kit itself is faulty.
Quite simply: his Bleach bath didn’t do its job properly. He’s turned a barely reduced negative from the first development into a positive in the second development; that’s a brilliant way to ‘turn film black’; anyone needing the cheapest IR filters for their digital camera will find what they’re looking for here.
He didn’t give the KMnO₄ enough time to dissolve – just before it reached zero, then barely stirring it at all… no.
“Incidentally, I have many years of experience in a photo lab.”
Nothing in a standard darkroom prepares you for the treachery of potassium permanganate.
“Even though I haven’t developed reversal film before, it should be perfectly possible for me to do this on my own if I have the necessary information.”
Hmm. If he was looking into this topic here or on the Phototec forum six months ago, he would have been shown our article.
"I’d like to send an email to Foma suggesting what could be improved in the instructions."
By all means: they should finally make a photocopy of the corrected preparation instructions for the Bleach bath, and while they’re at it, they can include the tip about Aqua Demin, filters and “shortly before, but not immediately”.
Everything else is also available in the usual place. ,-)
Roman
Stagirit
Commercially available potassium permanganate is now so heavily inhibited by manganese dioxide that its reactivity is significantly reduced.
Perhaps that is also the reason why this becomes rather noticeable in homemade flash powder.
Otherwise, I would speculate that it is down to the speed of the Bleach bath.
cfb_de
It depends on *what* you buy *and where*. If I buy potassium permanganate labelled ‘pure’, ‘p.a.’ or even ‘according to DAB/EuPh’ from a chemical supplier or, for that matter, a chemist’s, then the stuff is clean and not inhibited.
However, I have to put up with at least three questions.
If I buy “technical” potassium permanganate, I don’t have to answer three questions, but I’m only guaranteed a purity of 85%. That’s not inhibited either; it was already that dirty to begin with and won’t work as a Bleach bath without filtration. The same applies to “photo grade” purity: that’s equivalent to “technical” and is absolutely no mark of quality. On the contrary: this is the lowest quality that is currently permitted to be sold.
Only if I do not answer the famous three questions, or do not answer them correctly, will any responsible retailer automatically supply inhibited KMnO₄; *because* that would mean all the fun experiments for which it is predominantly bought would no longer be possible.
It’s still good enough for Granny’s foot bath, though, and that’s the main use of this chemical in the hands of end customers. The few grams per year for the handful of black-and-white reversal photographers (unfortunately) fall mercilessly by the wayside.
But you can still get the stuff through retail channels open to everyone on an annual basis.
Best regards,
Franz
PhilippReichmuth
Roman,
It was a desk lamp with a 40W bulb, with the film in a white plastic bucket with water underneath; I turned it over after a few minutes. I’d actually meant to fetch one of those 15W energy-saving bulbs from the canteen – that would have been the equivalent of about 70W or so – but I forgot in the end, and it worked fine as it was.
I can’t imagine that this amount of light wouldn’t be enough to provide the exposure needed to expose all the remaining silver in a standard film with 50 ASA or higher. In that respect, the amount of light probably wasn’t the problem. Besides, for logical reasons alone, the film shouldn’t turn black if you underexpose it during double exposure.
I think that, apart from the tips on the order of acid and water – which have already been corrected in the English data sheet – Foma should at least point out what to look out for with the Bleach bath: don’t prepare it too early or too late, and above all, filter it well; as we in SK have discovered the hard way, a coffee filter isn’t always enough either.
If Foma won’t budge: perhaps Mirko could include a note to that effect in the catalogue; it’s only a few lines, and that way he’d at least be on the safe side with his own customers as far as complaints are concerned.
Philipp
RomanJRohleder
Hi Philipp,
>I can’t imagine that this amount of light wouldn’t be enough to provide the exposure needed to expose all the remaining silver on a standard film with an ISO of 50 or >higher.
>
The amount required is minimal, as we amateur photographers all know. ;-)
Someone you now know said that ‘1000 lux, 15 seconds from both sides’ would suffice; but it doesn’t hurt to be safe – I couldn’t detect any increased base fog even in daylight.
>In that respect, the amount of light probably wasn’t the problem. Incidentally,
>for logical reasons alone, the film shouldn’t turn black if you >don’t double-expose it enough.
Yep. But perhaps the film’s logic module was faulty? <g>
>I think, apart from the tips on the order of acid and >water – which have already been corrected in the English data sheet –
That was never wrong there! That’s the embarrassing bit – some daft translator neatly mistranslated it into German – probably because it always said “A1+water”, “C1+water”, “D1+water” and then “water + B1 + B2” just fell out of the standard formula?
> As we discovered the hard way in SK, a coffee filter
> isn’t always enough either.
Yep. In future, homemade round filters or double-layer Melitta. Mind you: the little filter was fine; I did take it apart and check it again.
The gunk was probably floating in the stabiliser; someone had been munching on something in there.
>If Foma won’t budge: perhaps Mirko could >include a note to that effect in the catalogue,
As the ADOX Vario Classic example shows, the average customer is reluctant to look in the catalogue or is only partially able to put what they’ve read into practice. Keyword: “Red light. ONLY red light!” – “Can I use green instead?”. Argh.
>It’s only a few lines, and at least with his own customers he’d be >on the safe side as far as complaints are concerned.
Include a separate leaflet?
Roman
Stagirit
Off-topic:
Speaking of the DuKa lamp, I’ve got an old spectral lamp that I can’t use anymore because the starter’s broken.
Where can I get hold of an St 191 like that?
Gast
Roman,
Green light definitely works, because it works with every light-sensitive material available on the market. Admittedly, with green light (e.g. Agfa 108) you can barely see your own hand in front of your eyes, but that’s another matter.
Roland
cfb_de
Hi Stagirit,
Try an electrical shop. And if they don’t have it, do a Google search for “starter st191”. There are plenty of suppliers with a wide range of prices. At “t+s audio”, for example, for
RomanJRohleder
Roland,
Please don’t give those who haven’t read the catalogue notes any silly ideas. ;-)
“Green light is definitely an option,”
Have I missed something? Are you familiar with the debate surrounding Vario Classic, a VarioContrast paper? Green light is generally classified within the 490–570 nm spectrum, but the paper in question already causes problems with orange (600–640 nm).
“because it works with every light-sensitive material available on the market,”
But with MG/VC papers, it’s a moderately good idea.
“Admittedly, with green light (e.g. Agfa 108) you can barely see your own hand in front of your eyes, but that’s another matter.”
Besides, green light is disgusting – your fellow developers stand next to you with sickly complexions... ;-)
Roman
Gast
Roman,
It’s actually quite simple: every light-sensitive material has a narrow sensitivity gap in the green spectrum (olive green/dark green) that has never been successfully bridged, which is why green foliage sometimes appears very dark.
I’ve explained this here before.
Roland
RomanJRohleder
Roland,
I have a vague recollection of a debate about LEDs, secondary spectra and all sorts of other things. ;-)
Viewed objectively, you’re right – but I don’t think it’s helpful to tell people “green works” when, in reality, green already causes problems with the specially sensitised papers from Ilford or Agfa; not to mention the extremely finicky Vario Classic.
If the 108 fills the gap you mentioned exactly, what’s the situation regarding new purchases and replacements for filters that have reached the end of their users’ lifespans and let through significantly less light?
Roman
Gast
Roman,
The last sentence seems to me to be clearly a rhetorical question (one where you already know what my answer would be: the filter is no longer available as such – I suspect you’re well aware of that too – the Philips bulbs are still available as clearance stock from specialist lighting retailers (production ceased a few years ago), as far as I know, AP still manufactures a green cap of that type, though it isn’t available in Germany.
However, the 108s were rarely used and are likely still mostly in good condition; and if anyone needs a new one, they’ll probably go for a red one anyway.
Roland
