Perceptol and Box Speed - I'm a little puzzled.

I had always assumed Perceptol as a speed reducing developer until I had the job of trying to reduce to a minimum the grain on a friend's D3200 film which he had shot at box speed. I was surprised but glad to find that there was a development time for D3200 at box speed and on closer reading of the Perceptol intro, mention is even made of its ability to cope with D3200 at box speed as a grain reducing asset.

I developed it and was pleasantly surprised at how much more grain free the negs were compared to ID11.

Given that it works very well with D3200 at box speed, it surprises me that there's no time for D400 at box speed although there is for D100 at box speed. Looking through the Ilford dev tables there seems to be several anomalies. There no box speed dev time for HP5+ although there is on the Massive Development Chart. There is only box speed dev times for Tmax 400 and none for any speed reduction.

Fuji Neopan 400 is also listed at box speed but not Fuji 1600 at any speed. Likewise Tmax 3200

OK it may be that Ilford haven't tested all non Ilford films at various speed but my questions are:

If it can handle D3200 at box speed then why no times for some slower films such as D400 or HP5+ at box speed?

If it can handle films at box speed, does it still produce the same grain as it would at say 1 stop slower. Given that over exposure, which downrating is, produces coarser grain then do we get the best of both worlds by box speed and Perceptol?

If not, then what's the trade-off between full box speed development and 1 stop lower development, apart from the obvious drawbacks of lower speed on camera exposure settings.

What is likely to be the difference in the negs by say developing D100 at 50 and D100 at 100. Likewise D3200 at 1600 compared to D3200 at 3200?

pentaxuser

Hi pentaxuser,
I'm not confident I have the answer, but one interesting fact about D3200 is that box speed is actually a push process. I think the true speed of the film is somewhere in the ISO 1200 region, but please don't quote me on that.
So at 3200 you would be under-exposing the film. I woder if that fact holds some of the explanation?
- Thomas

it's not a 'speed reducing developer' as far as I know. Just supposed to be an early attempt at an acutance developer.

Sparky said:

it's not a 'speed reducing developer' as far as I know. Just supposed to be an early attempt at an acutance developer.

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Undiluted Kodak Microdol-X (aka Ilford Perceptol) is an excellent general purpose fine grain film developer. Diluted, Microdol-X is an excellent acutance developer.

from what I understood, Tom - microdol-x is phenidone based... while similar to metol - it's kind of different - I also understood microdol-x to contain more grain-melting sulfites. But that's just my understanding of it. I could be wrong. I'd like to hear what someone who really knows the differences have to say.

Metol is the reducing agent in Microdol-X and Perceptol

Sparky said:

from what I understood, Tom - microdol-x is phenidone based... while similar to metol - it's kind of different - I also understood microdol-x to contain more grain-melting sulfites. But that's just my understanding of it. I could be wrong. I'd like to hear what someone who really knows the differences have to say.

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No, Metol is the reducing agent in both Microdol-X and Perceptol. use Google and Check the Material Safety Data Sheets for both developers and be sure to get the most current MSDS for both. Both developers contain Sodium sulfite and both contain Sodium Chloride. Grant Haist has written about this subject in Modern Photographic Processing - there is an APUG thread that discusses this subject.

Okay - hmm... maybe I was thinking of microphen...

I have never got satisfactory shadow details when I've used perceptol on films exposed at "film box" speed - my personal testing has always suggested I need at least 2/3 stop over exposure with most films. If you have found that you do get the detail you want at box speed, the that's great.

I imagine that ILFORD dont give times for various films because they do not recommend that combination - possibly because of long development times or other reasons ... it doesnt mean you cant use the developer as you wish, they just feel there are better alternatives. the Massive dev chart is a little bit like a free for all as it is reader informed - what you see there is something that someone has tried and found useful.

Leon said:

I have never got satisfactory shadow details when I've used perceptol on films exposed at "film box" speed - my personal testing has always suggested I need at least 2/3 stop over exposure with most films. If you have found that you do get the detail you want at box speed, the that's great.

I imagine that ILFORD dont give times for various films because they do not recommend that combination - possibly because of long development times or other reasons ... it doesnt mean you cant use the developer as you wish, they just feel there are better alternatives. the Massive dev chart is a little bit like a free for all as it is reader informed - what you see there is something that someone has tried and found useful.

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Thanks all for replies so far.

Leon. Thanks for yours, coming, as it does, from actual experience. My understanding of what you have said is that Perceptol at box speed gives the gain of the same fine grain that's there at 1 stop less but with the loss of some shadow detail compared to better shadow detail and the same grain but the loss of speed. Equally I'd assume from this that in a trade-off with a box speed developer compared to Perceptol at box speed, it's a case of better shadow details with coarser grain but full speed. So the pluses for the box speed developer are better shadow details and full speed and the minus is coarser grain.

This makes sense but I still find it strange that despite acknowledging its speed reducing aspect, Ilford actually make a point of highlighting its benefits for D3200 at box speed. If generally it's better to use it at a lower EI and Ilford make no secret of this as most dev times are for lower than box speed, then you might expect a paragraph which at least hints at some loss of shadow detail at box speed which is restored at a lower EI but if the conditions demand box speed with D3200 that Perceptol is a very good tamer of grain with a little loss of shadow detail. This would hardly be the equivalent of the fishmonger crying" stinking fish" from his stall.After all D3200at EI 1600 still leaves the photographer with a very high speed.

I am sure that you are right in saying that issuing no times for certain combos indicates that Ilford believes that there are better combos but it hardly explains times for Fuji Neopan 400 at box speed and only box speed. If its OK for Fuji 400 at box speed then why not Fuji 400 at say EI 320,250 or 200?

Anyone else's experience with Perceptol at box speed is most welcome or who can cast light on the other "anomalies" for want of a better word.

Thanks

pentaxuser