8 Year old Perceptol - Whether to use for film?

pentaxuser · Feb 26, 2019

I have just discovered a winebag with 8 yr old Perceptol in it. I tried the "clip test" and it worked to the extent that the exposed clip appeared to turn completely black using the Ilford time for HP5+ @250( my film speed) in stock. My test consists of holding the clip up to a 100W incandescent light filament to see how much light the filament gives through the clip. It turns the filament an orange colour and the wire can easily be seen without any kind of dazzle. This is my usual test but I compared it to a clip I developed in what |I know to be fresh Xtol and there was a slight difference. The filament developed in Perceptol was brighter than the one against the Xtol clip but not by a lot. Frankly in daylight and not against a light filament I probably would not have seen a difference. I should also add that the Perceptol was no longer clear but close to the colour of light tea.

If the Perceptol is now exhibiting the effect described above, i.e. it still turns a clip black then (a) how is this likely to show up if used for an exposed film and (b) if the Perceptol works to the extent described above, what if anything does an extension of the development time accomplish? Can an extension of time compensate at all?

I assume that the answer to (a) above may be that the film will contain images but these may be the equivalent of under-developed film and the answer to (b) may be that no amount of extra time will compensate.. However I don't know so answers, especially from those who did a clip test with similar results and then developed a film , will be welcome

Thanks

pentaxuser

Andrew O'Neill · Feb 26, 2019

I'd be tempted to go ahead and increase the development time... But then again, I'd probably discard it and use fresh stuff. I developed a roll of film in 7 year old Ilfosol that i found in my school's darkroom cupboard . Increased the time by 25%. Negatives looked under developed. Shot of another short roll, and increased by 50%. Slight improvement but still looked under. Scanned in nicely, though.

Alan Johnson · Feb 27, 2019

I obtained a similar result to the OP when testing 5 year old perceptol contained in a sealed plastic bottle for the recommended time.
So far I have not managed to figure out if this density loss is due to air slowly diffusing through the plastic or some kind of hydrolysis.

pentaxuser · Feb 27, 2019

Thanks both for answers. On balance and because I have at least some frames that would not be easy to take again I'll use fresh Xtol. I was able to try both clips in daylight today and in fact the difference between the two is clearer than appears under a light bulb filament at night Leafless tree branches can be seen fairly clearly through the Perceptol clip but are much darker through the fresh Xtol clip

An interesting discussion nonetheless. Your replies and negs would seem to confirm that once a developer is on the way out then no amount of additional time can make up for it. It might just be that if the HP5+ developed at 400 in fresh Xtol were to be exposed at 100 rather than 250 and then developed in Perceptol past its best for a lot longer than the normal time for HP5+ at 100 in Perceptol then you might be able to "improve" the negs slightly but I don't know.

There is no doubt a chemical explanation as to what has actually happened to the developer which might lead to an answer to the above situation in my second paragraph but its then a "what if" discussion prompted by curiosity.

It becomes the theoretical question posed as the following scenario: If it was the last old developer in all the world and it walked into my darkroom what is the best that can be done to get a printable negative - as Rick would say

pentaxuser

Alan Johnson · Feb 27, 2019

If the Perceptol is similar to its substitute formula it originally contained about 5g/L metol.
If there is still enough metol left to develop one film, it should work given long enough.( My 5 yr old sample had a pH by paper about 7.5, not much different from fresh Perceptol ).
You noted something else that is not known, if the metol is noticeably oxidized before most of the sulfite has gone..

trendland · Feb 27, 2019

pentaxuser said:
I have just discovered a winebag with 8 yr old Perceptol in it. I tried the "clip test" and it worked to the extent that the exposed clip appeared to turn completely black using the Ilford time for HP5+ @250( my film speed) in stock. My test consists of holding the clip up to a 100W incandescent light filament to see how much light the filament gives through the clip. It turns the filament an orange colour and the wire can easily be seen without any kind of dazzle. This is my usual test but I compared it to a clip I developed in what |I know to be fresh Xtol and there was a slight difference. The filament developed in Perceptol was brighter than the one against the Xtol clip but not by a lot. Frankly in daylight and not against a light filament I probably would not have seen a difference. I should also add that the Perceptol was no longer clear but close to the colour of light tea.

If the Perceptol is now exhibiting the effect described above, i.e. it still turns a clip black then (a) how is this likely to show up if used for an exposed film and (b) if the Perceptol works to the extent described above, what if anything does an extension of the development time accomplish? Can an extension of time compensate at all?

I assume that the answer to (a) above may be that the film will contain images but these may be the equivalent of under-developed film and the answer to (b) may be that no amount of extra time will compensate.. However I don't know so answers, especially from those who did a clip test with similar results and then developed a film , will be welcome

Thanks

pentaxuser

I made different experience Pentaxuser. There should be something wrong with your Perceptol.
Perhaps the package is damaged (humidity)?
I bought some 1983/1986/1990 perceptol stuff on EBay! Beside the nice looking package design
of different periods (Ilford changed it some times a little) the perceptol I made experience is
100% comparable with fresh stuff.
But from direkt comparison to XTol there have to be of course a difference (I am sure you are eelk knowing this)/
The contrast with Perceptol has to be a little soft in comparison. The "visual" sharpness impression
is a little more low in general. (more resolution from finest grain isn't the same like sharpness we feel as "sharp"! ( more contrast looks allways " sharper" ...but isn't in reality).
That what perceptol do with a bw film is to me allways a "special kind" of pull development.
Some will not agree (I know) but to me it is "like" pull development ! (Beside other characteristics of Perceptol)
with regards

trendland · Feb 27, 2019

Perhaps I missunderrstood you ? You used a "wineback" of Perceptol 8 Years old? So if you use
mixed perceptol (liquid) it is OK that your film did not show so much..,?
But the question was in regard of why your film is showing something?

Perhaps old Pepsi Cola would also show something on an exposed film(maybe 8years old Pepsi)
But well stored (powder) Perceptol is allways better......?

with regards

trendland · Feb 27, 2019

Alan Johnson said:
I obtained a similar result to the OP when testing 5 year old perceptol contained in a sealed plastic bottle for the recommended time.
So far I have not managed to figure out if this density loss is due to air slowly diffusing through the plastic or some kind of hydrolysis.

View attachment 218277

OK seams to be I am learning something in addition (Perceptol can be stored in liquid over years)?

But what does the metol make this longest time with oxigen? It don't want to be married?!

Damned

with regards

Slixtiesix · Mar 1, 2019

An interesting thread to follow! I usually toss away my Perceptol after one year.

8 Year old Perceptol - Whether to use for film?

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