Foma 100R in Fomakit failed...

matvogel · 2011-09-28T20:54:53+00:00

Hallo Forenten und Dia-Fans, habe heute Abend meinen ersten Foma 100R im Fomakit umkehrentwickelt und mich peinlich genau an die Vorschrift im Prozess nach...

matvogel

Hello forum members and slide film enthusiasts, This evening I processed my first roll of Foma 100R in the Fomakit using the Hilgert/Rohleder process, following the instructions to the letter, as is recommended in many places. http://www.schwarzweiss-magazin.de/swmag_leser_09.htm Foma’s official instructions are now very similar; only the rinsing times differ. Unfortunately, my film is completely black. I can make out all the images – they have been correctly reversal-developed – but they appear on the black base as nothing more than faint, positive traces. Not a trace of transparency to be seen... The only deviation from the Hilgert/Rohleder instructions was that I only added the Bleach bath after stopping the initial development, rather than leaving it to stand for 15 minutes as recommended by Hilgert/Rohleder. Numerous other posts have consistently pointed out that the Bleach bath runs out extremely quickly. It’s hardly possible to overexpose it too much, is it, or am I mistaken? I held a 150 W halogen spotlight at a 10 cm angle from above in front of the film, inside a transparent CD-100 canister filled with water, and kept turning it nicely – 3 minutes, then turned the Jobo reel over and another 3 minutes. Too much of a good thing? Oh, and the temperature was just under 21 degrees... Do you have any idea what went wrong? Many thanks and best regards Matthias

Junkom

So, I’ve had a few beers now and I’m not really thinking straight, but your lamp – which is quite bright – did you hold it up to the undeveloped film? Did you develop it under that light, or did you just look at the film with it after the fixer? The first would probably be the reason; the second would be fine. Why don’t you scan a sample? Black and yet still being able to see something sounds odd…

thomas_l

I can’t quite picture what a positive image on a black background would look like either, but if something that’s supposed to be transparent is black, then I’d guess the bleaching didn’t work. Best wishes, Thomas

matvogel

I can’t quite picture what a positive image on a black background would look like either, but if something that’s supposed to be transparent is black, then I’d guess the bleaching didn’t work. Best regards, Thomas

Exactly, the base is pitch black throughout. You can make out every image, but only when viewed from above; in other words, you can see the image traces clearly and distinctly in the emulsion as a positive. I just wonder what I did wrong during the bleaching process. I used 270 ml of distilled water, then added 30 ml of sulphuric acid from the Fomakit, followed by the 30 ml of dissolved potassium permanganate from the kit, gave it a quick stir, and then poured it into the tank. I tilted the tank in the usual way for the prescribed 8 minutes (3 tilts every 30 seconds). I’m at a loss...

Tandemfahren

Hi there, So @Junkom, he obviously held the film—which had already been developed and bleached—up to the light. How many beers? ;-) As someone with no experience of black-and-white slides, my first thought is that the shots might well have been underexposed right from the moment they were taken. I’m the sort of person who makes the most outrageous mistakes. Accidentally leaving the camera on ‘M’, setting the wrong ISO... My second thought is that the initial development might have been inadequate. Developer gone off, wrong mix (my classic mistake: Rodinal 1:250 instead of 1:25), time too short/not agitated enough, etc. I can’t say anything about the bleach bath due to lack of experience. And no, you probably can’t suffer from overexposure. My two cents. Please keep me updated, as I’d like to have a go at this myself. One more thing: the ‘base’ (i.e. the image edge and the spines. The emulsion is black, not the base) is naturally black after successful reversal development – what did you expect? Regards, Frank

matvogel

Of course, the base is transparent polyester. I just wanted to point out that the entire film is black, meaning it has been successfully reverse-developed. The images are definitely correctly exposed; I don’t use automatic cameras and rely solely on my manual exposure metering. When I look at the emulsion at a slight angle, I can see the images very clearly in the reflected light. So it really does seem to be a problem with the bleaching.

Tandemfahren

Hi Matthias, I certainly didn’t mean to make you look like a fool. I just wanted to make sure we weren’t going down the wrong track. I suppose there’s no choice but to go back to square one. And here’s my request again: an interim report! I don’t want to end up falling into the same trap, do I? Best regards, Frank

Berferd

I think the problem lies in the phrase ‘stirred briefly’ – the potassium permanganate actually takes quite a while to dissolve completely. Because the solution turns dark purple quite quickly, it’s hard to see any undissolved lumps. If the emulsion wasn’t completely pale yellow (i.e. the images were barely visible) during the intermediate exposure, something went wrong with the Bleach bath.

matvogel

I think the problem lies in the phrase ‘stir briefly’ – the potassium permanganate actually takes quite a while to dissolve completely. Because the solution turns dark purple quite quickly, you can’t see the undissolved lumps very well. If the film wasn’t completely pale yellow (i.e. with almost invisible images) during the intermediate exposure, something went wrong with the Bleach bath.

The potassium permanganate is already present in dissolved form in the current Fomakit. So it doesn’t need to be dissolved for a long time or filtered, as was necessary in the past. The film was lemon-yellow after I took it out of the clearing bath. Then came the light bombardment described, using my 150W construction spotlight...