josephchesshyre
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Hello all, I'm new around here although I've been hovering for a few months as I've been interested in b&w reversal for a while.
I've been following the Ilford instructions with a couple of modifications. Firstly, I've halved the amount of KMnO4 in the bleach having read that this was a good idea. The bleaching seems to be working perfectly like that, even when sticking to the specified 5 minutes.
The other change I've made concerns the sodium thiosulphate that Ilford specifies at a concentration of 8-12g/l in the first developer. It has quickly become clear to me (no pun intended) that this is too much. My first roll of film came out extremely faint and seemingly over-exposed, with some frames completely blank. Initially I blamed this on too much bleach, but when the same thing happened with my second film and following some extensive online reading I decided that the sodium thiosulphate was to blame.
These first two rolls were Ilford FP4 exposed at box speed. Several online posters have suggested that the amount of thiosulphate that Ilford recommends is based on older films with much thicker emulsion than modern films, and although this makes sense it strikes me as odd that Ilford specifically mention FP4 as requiring 12g/l of thiosulphate. Could it be that even their own films have changed since that document was written?
The third roll I developed was HP5. Although Ilford say that this is likely to yield slides with 'unacceptably low contrast', this roll actually turned out beautifully, but based on several articles I read I added NO thiosulphate at all. The results are anything but lacking in contrast - if anything they are verging on too contrasty!
E.g.
My fourth film was one of Kodak TMax 100 that I had lying around waiting to be developed for a while. This turned out brilliantly with 12g/l thiosulphate, but I know these films have notoriously thick emulsion.
My fifth film was another FP4. Here are a couple from it, my most successful so far.
With this roll I omitted the thiosulphate from the first developer but used a bath of it at 10g/l after the bleach clearing bath and before second exposure. Looking back now that I've developed a sixth film, I don't think I really held it in this bath long enough to make more than a tiny difference and could possibly have done without it.
So, for my sixth film, which was of the same oil refinery but at night and so with a lot of black in many of the shots, I used the same method but with more time in the post-clearing thiosulphate bath. I kept checking and could hardly see any change occurring, so kept going, for a total of four minutes in the thiosulphate bath. Much to my irritation this film has turned out badly. The images aren't too faint because they're mostly dark-ish as I say, but all the blacks are dark greys (include the film edges) and some of the shots with the longest exposures are almost completely invisible. In general there is a washed-out look and a lack of richness. All images also have bad 'swirling' and what looks like silver 'run-off' across the image from the halide in the film edges.
I'd rather cut out this extra thiosulphate stage as it seems unpredictable and not very accurate, and although the idea of clearing the highlights by inspection appeals to me, in practice it doesn't seem that easy to do, especially if the images don't have many highlights or large bright areas.
Does anyone else have experience of adjusting this parameter, especially with Ilford films? Does anyone have any idea why the amount in the Ilford directions is clearly too high? Some other recipes posted on here over the years have included much smaller amounts of sodium thiosulphate than Ilford specify. I really want to get to the stage where I know how much thiosulphate to add to the first developer, both for HP5 and FP4 (the two films I use most) without wasting too many more films and chemicals.
I'm thinking that for my next roll of FP4 I will shoot at box speed as before and add 1g/l thiosulphate and take it from there.
By the way, I'm using Ilford Universal PQ at 1+5 and developing for 12 mins at 20C with an inversion every 15 seconds, i.e. exactly what Ilford recommend.
I've been following the Ilford instructions with a couple of modifications. Firstly, I've halved the amount of KMnO4 in the bleach having read that this was a good idea. The bleaching seems to be working perfectly like that, even when sticking to the specified 5 minutes.
The other change I've made concerns the sodium thiosulphate that Ilford specifies at a concentration of 8-12g/l in the first developer. It has quickly become clear to me (no pun intended) that this is too much. My first roll of film came out extremely faint and seemingly over-exposed, with some frames completely blank. Initially I blamed this on too much bleach, but when the same thing happened with my second film and following some extensive online reading I decided that the sodium thiosulphate was to blame.
These first two rolls were Ilford FP4 exposed at box speed. Several online posters have suggested that the amount of thiosulphate that Ilford recommends is based on older films with much thicker emulsion than modern films, and although this makes sense it strikes me as odd that Ilford specifically mention FP4 as requiring 12g/l of thiosulphate. Could it be that even their own films have changed since that document was written?
The third roll I developed was HP5. Although Ilford say that this is likely to yield slides with 'unacceptably low contrast', this roll actually turned out beautifully, but based on several articles I read I added NO thiosulphate at all. The results are anything but lacking in contrast - if anything they are verging on too contrasty!
E.g.
My fourth film was one of Kodak TMax 100 that I had lying around waiting to be developed for a while. This turned out brilliantly with 12g/l thiosulphate, but I know these films have notoriously thick emulsion.
My fifth film was another FP4. Here are a couple from it, my most successful so far.
With this roll I omitted the thiosulphate from the first developer but used a bath of it at 10g/l after the bleach clearing bath and before second exposure. Looking back now that I've developed a sixth film, I don't think I really held it in this bath long enough to make more than a tiny difference and could possibly have done without it.
So, for my sixth film, which was of the same oil refinery but at night and so with a lot of black in many of the shots, I used the same method but with more time in the post-clearing thiosulphate bath. I kept checking and could hardly see any change occurring, so kept going, for a total of four minutes in the thiosulphate bath. Much to my irritation this film has turned out badly. The images aren't too faint because they're mostly dark-ish as I say, but all the blacks are dark greys (include the film edges) and some of the shots with the longest exposures are almost completely invisible. In general there is a washed-out look and a lack of richness. All images also have bad 'swirling' and what looks like silver 'run-off' across the image from the halide in the film edges.
I'd rather cut out this extra thiosulphate stage as it seems unpredictable and not very accurate, and although the idea of clearing the highlights by inspection appeals to me, in practice it doesn't seem that easy to do, especially if the images don't have many highlights or large bright areas.
Does anyone else have experience of adjusting this parameter, especially with Ilford films? Does anyone have any idea why the amount in the Ilford directions is clearly too high? Some other recipes posted on here over the years have included much smaller amounts of sodium thiosulphate than Ilford specify. I really want to get to the stage where I know how much thiosulphate to add to the first developer, both for HP5 and FP4 (the two films I use most) without wasting too many more films and chemicals.
I'm thinking that for my next roll of FP4 I will shoot at box speed as before and add 1g/l thiosulphate and take it from there.
By the way, I'm using Ilford Universal PQ at 1+5 and developing for 12 mins at 20C with an inversion every 15 seconds, i.e. exactly what Ilford recommend.
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