Florek
Dear forum members
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In our student photography lab, a few users have tried out the RPX 100 and are struggling
with (water) spots on the base side. Other films are not affected. In the standard process,
Lobostab, prepared with water of distilled quality, is used. The films are dried in a drying cabinet
at room temperature for approx. 45 minutes. I have now tried it myself with distilled
water without a wetting agent:
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Concentric rings form on the base side where water was present during drying. When using
a wetting agent (including Mirasol and Rollei Wetting Agent!), they have spread out due to gravity and look
more like "blobs".
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Has anyone had similar experiences? Is it possible that RPX has a coating on the back
that causes problems during drying? I’m a bit stuck at the moment and would be grateful for any tips!
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Regards,
Florian
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grommi
Hi Florian,
I struggled with this at first too, with various films, and we have hard water. I tried just about everything! The solution came from a forum and is simple. For quite some time now, I’ve been wiping my films with a streak of cellulose kitchen roll (Zewa etc.) that I’ve folded several times into a narrow streak and then into a V-shape. Goodbye water marks, no scratches, very clean negatives, film dry in 1/2 – 1 hour without a drying cabinet. I use a drop of washing-up liquid as a wetting agent, because I only got marks with Agfa Agepon too. Yeah, I know…… Praise be to whatever works.
Best regards, Reinhold
PS: With RPX, you now have to distinguish between the 100 and 400 on the one hand and the new 25 on the other. The latter is cast on PE and doesn’t seem to me to come from England either. But that’s just a side note. Because for the wiping method described above, it’s irrelevant; it works with any film.
hubspe
Hello there,
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Concentric circles sound more like air bubbles, though.
The Ilford Delta 100 4x5-inch film had a problem with air bubbles years ago. It helped to pour the developer into the can in such a way that it didn’t bubble, and to bang the can firmly on the table every minute.
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Stripping films or negatives, however you do it, is something I’d never do again after a bad experience. It’s simply a risk that’s easy to avoid....
bernhardmangelsgmxde
Yes, I’d be careful when wiping them down too; I’ve already scratched a few films doing that. But if you only do it on the backing side (which is where the water marks are in this case), there shouldn’t really be any problems
grommi
Hubspe, namir, which method of wiping did you have a bad experience with? Sure, rubber squeegees, chamois leathers or whatever else people use – that sort of thing happens in a flash. But with new kitchen roll, I reckon it’s virtually impossible. I always fold it in the air rather than on the table, and I fold the outer layer inwards, so foreign particles don’t stand a chance.
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PS: air bubbles stretched out by gravity???
TR
In our student photo lab, the wetting agent is always prepared far too concentrated. That’s why I use my own there, with a 1:1000 dilution in distilled water as a multi-use solution. Even in the electric drying cabinet, my films come out spotless. It works without the need for stripping. However, my experience doesn’t specifically relate to the RPX 100.
hubspe
Hubspe, namir, which method of wiping did you have a bad experience with? Sure, a rubber squeegee, a chamois leather or whatever else people use – that sort of thing happens in a flash. But with new kitchen roll, I reckon it’s virtually impossible. I always fold it in the air rather than on the table, and I fold the outer layer inwards, so there’s no chance of any foreign particles getting in.
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PS: air bubbles stretched out by gravity…
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Apart from bad experiences, common sense alone tells you it’s a risk.
An emulsion that’s still soft and mechanical stress, however slight,
can be a problem.
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A wetting agent correctly diluted in distilled water, along with gently soaking the negatives in it and hanging them up in the drying cabinet, has worked without any problems for me for about 20 years. Why on earth would I suddenly start wiping the soft emulsion with kitchen roll? :)
grommi
Apart from the fact that this doesn’t answer my question about the stripping method and my bad experiences with it, common sense would suggest that it might be beneficial to have as little residual water as possible drying on the film. In any case, I now have extremely clean negatives; even under close scrutiny, spot cleaning is virtually no longer necessary. That was a real eye-opener for me. But as always, there are many ways to skin a cat, and what’s the harm in trying something different when you’ve got existing(!) problems?
hubspe
But as always, there are many ways to skin a cat, and what’s the harm in trying something different when there are existing(!) problems?
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Nothing, but you should also clearly address the risks, which is what I’ve done. ;)
AntiLynd
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Apart from the fact that this doesn’t answer my question about the scraping method and bad experiences,
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I can’t contribute anything regarding bad experiences with stripping methods, but I can certainly contribute to the good ones:
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bernhardmangelsgmxde
Hubspe, namir, which method of wiping did you have a bad experience with? Obviously, rubber blades, chamois leather or whatever else is used – it happened in a flash.
With rubber film scrapers anyway; with windscreen wipers it was even worse, and kitchen roll has also left me with a few telegraph wires – though I can’t rule out the possibility that there were a few crumbs or something in there somewhere. I’ve also tried this (not with the film folded V-shaped and scraping both sides at once, but with the film hung up and scraping each side individually) and got good results. I keep wondering whether it might be worth getting one of those lab spray bottles and giving the film a quick shower with deionised water after hanging it up... Telegraph wires are just a bit of a nuisance, especially if you want to enlarge the image (it’s not so bad with hybrid processing, as you can retouch them using digital editing). In my experience, I also see a definite risk when using kitchen roll.
Neutrino
In my experience, the best way to ensure a film comes out completely spotless is to use demineralised water from a DIY store. After the film has been thoroughly rinsed with normal tap water, I fill the canister with demineralised water about 2–3 times. Then, just to be on the safe side, I run the film through a small bowl of demineralised water once more. After this final rinse, I hang the film up as it is and wait until it is completely dry. Using this method, I have never, ever had even the slightest smudge or scratch on the film. Wetting agents, film scrapers and fingers have, in most cases, led to smudges and scratches to a greater or lesser extent.
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The downside of this method is the relatively high cost. A 5-litre canister costs me about €1.60 in my area. I use roughly 2 litres per film. That works out at about 65 cents extra per film. But as I don’t develop that many films a year, I treat myself to this ‘luxury’. It still works out cheaper than taking the film to a lab, and the films don’t always come back spot- and scratch-free from there either. Apart from that, with a lab you have no say in the developer used, etc.
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Another minor drawback I see with this method is the relatively long ‘wet phase’ of the film whilst it’s drying. As it takes a bit longer to dry completely, dust particles theoretically have more time to stick to the film. I haven’t actually noticed any difference in the amount of dust embedded in the film yet, though I haven’t written any studies on the subject either. ;-) If you hang the film up in a relatively dust-free place, it shouldn’t be a problem!
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I can’t say to what extent the film is actually less protected if you don’t use a wetting agent. But if it’s stored properly, that shouldn’t cause any problems either. At least I haven’t read anything negative about it, and I haven’t noticed anything myself either.
Florek
Many thanks for all the information!
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It is striking that this only affects this particular film, and we have had very good results in the lab using distilled water + wetting agent in a lower dilution than specified. I think the kitchen paper is a viable solution for a student lab, as any ‘incorrect use’ does not affect the next user and, in this case, only the backing needs to be dried. A rubber squeegee may contain contaminants or be damaged by the previous user. We see this time and again with the baryta dryer, where the tensioning cloth is covered in fixer stains. Personally, I always prefer natural drying without any mechanical components.
And from a technical point of view: can individual water droplets on the support side actually cause an emulsion to swell, resulting in an uneven finish? This effect is, after all, not unknown on the emulsion side.
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Perhaps I’ll manage to produce a scan by the end of this week – maybe the shape will then reveal the source of the problem.
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Thanks again!
Florian
Urnes
Why not try tap water, a standard dilution of wetting agent, wiping with your fingers if you’re using roll film or black-and-white film, and air-drying at room temperature?
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Regards, Sven.
plaubelpeco
...but don't cut them up too small! :)
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I haven't had this problem with GF Film yet. My films are rinsed using the Ilford method, given a final 1.5-minute bath in Ilfotol, and hung up to dry on a corner. No spots or anything.
piu58
> the new 25mm film. The latter is cast on PE and doesn’t seem to me to come from England either
This is an aerial photography film, Agfa Aviphot Pan 40. The two data sheets confirm this:
http://www.macodirect.de/download/Rollei_RPX_25_dt.pdf
http://www.agfa.com/sp/global/en/binaries/AVI_PAN40_tcm611-57409.pdf
The spectral sensitivity curves are particularly illuminating. This film can therefore be used with an IR filter, just like Rollei Retro 80 and Superpan 200.
Tandemfahren
>The latter is moulded from PE. Uwe, that’s PET. I know, I’m being a stickler... but you do see that sort of thing a lot.
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Frank
bernhardmangelsgmxde
> the new 25mm film. The latter is cast on PE and doesn’t seem to me to come from England either
That’s an aerial photography film, Agfa Aviphot Pan 40.
Maco denies this; see
http://aphog.de/forum/viewtopic.php?f=4&t=32040&start=15
piu58
> Maco denies this
Maco doesn’t produce films itself. Where on earth else is the film supposed to have come from? And is this complete similarity in spectral sensitivity just a pure coincidence?
adophil
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<blockquote class="ipsBlockquote" data-author="piu58" data-cid="18038" data-time="1415516334">
<div>
> the new 25. The latter is cast on PE and doesn’t seem to me to come from England either
That’s an aerial film, Agfa Aviphot Pan 40.
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Maco denies this, see
http://aphog.de/forum/viewtopic.php?f=4&t=32040&start=15
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</DIV>
</BLOCKQUOTE>
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… but only as a reference to sheet film. What about 35mm and medium format?
