XP-2 Super at room temperature?

I'm looking forward to shooting and processing XP-2 Super slit for Minox, and because the Minox daylight loading tank isn't very practical for temperature maintenance I hope to do it at room temperature. I should only need to adjust time for temperature, since there aren't any color layers to get out of balance with slower development. My calculation (at 4% per degree F) gives about 10:40 as a working time at 68F/20C -- has anyone done this who can confirm the time?

XP2 can be developed in B/W chemistry to get excellent results.
I use Rodinal 1+25, 12 min at 68°F, EI of 200...YMMV, of course.

AnselMortensen said:

XP2 can be developed in B/W chemistry to get excellent results.
I use Rodinal 1+25, 12 min at 68°F, EI of 200...YMMV, of course.

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While true (and (I've done it in Df96 monobath), that doesn't get me the extra effective speed of bleach bypass, with both dye and silver density. C-41 color developer will, I'm just trying to confirm the calculation of the time.

Donald, I had a quick look at what Google gives in terms of sources and precious little is the answer. I asked the specific question about it on Google and got the now ever-present AI answer which was that you could do it but it wasn't optimal. It then proceeded to give me the reasons why it wasn't optimal by telling me that the issues that arise with colour film

So I put in the word chromogenic in my description of the film and lo and behold it told me exactly the same thing all over again

The strange thing is that while I have in the past looked at several videos on XP2 Super, I cannot recall anyone mentioning anything about "the how" of developing it in room temp C41

Best of luck with a satisfactory answer

pentaxuser

I'll let the scientists respond more authoritatively than I can.
But I would be concerned if the structure of XP-2 includes multiple couplers that respond differently to different parts of the light spectrum.
Changing the development temperature might have an effect on the spectral response of the film.
That may not happen, or it may not matter to you even if you are both developing the film yourself, and sending other rolls to a lab.

MattKing said:

I'll let the scientists respond more authoritatively than I can.
But I would be concerned if the structure of XP-2 includes multiple couplers that respond differently to different parts of the light spectrum.
Changing the development temperature might have an effect on the spectral response of the film.
That may not happen, or it may not matter to you even if you are both developing the film yourself, and sending other rolls to a lab.

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Harman only mentions the advantages of its ability to be developed in a commercial lab at the normal C41 temp with no adverse affect on other colour film processing but makes no mention of the effect of using C41 chemicals at less than the standard 100F It's as if it doesn't expect anyone who wants to try it in the C41 process at home to think of room using temperature

However if less than 100F were to create problems you might think that it would at least say something to that effect so does this mean that it is OK to do what Donald proposes or not but Harman has never given it any thought and doesn't even know what if any adverse effects will arise as it has never tried to process it at less than 100F ? The later is unlikely or so I'd have thought

Either way I suspect we may have few, if any, users who have done what Donald is proposing. So he can either be a pioneer and do it or can write to Harman and ask them, just in case that Harman has a definite answer but hasn't made any mention of it in its instructions because it assumed that either users take it to a lab where 100F is the norm or are set up for colour processing at home and will therefore choose 100F because that is the known guaranteed process and is quicker?

Over to you, Donald.

pentaxuser


pentaxuser

pentaxuser said:

Harman only mentions the advantages of its ability to be developed in a commercial lab at the normal C41 temp with no adverse affect on other colour film processing but makes no mention of the effect of using C41 chemicals at less than the standard 100F It's as if it doesn't expect anyone who wants to try it in the C41 process at home to think of room using temperature

However if less than 100F were to create problems you might think that it would at least say something to that effect so does this mean that it is OK to do what Donald proposes or not but Harman has never given it any thought and doesn't even know what if any adverse effects will arise as it has never tried to process it at less than 100F ? The later is unlikely or so I'd have thought

Either way I suspect we may have few, if any, users who have done what Donald is proposing. So he can either be a pioneer and do it or can write to Harman and ask them, just in case that Harman has a definite answer but hasn't made any mention of it in its instructions because it assumed that either users take it to a lab where 100F is the norm or are set up for colour processing at home and will therefore choose 100F because that is the known guaranteed process and is quicker?

Over to you, Donald.

pentaxuser


pentaxuser

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If you're setup with temperature controls for C41 processing, why would you try room temperature other than as an experiment?
Not something to try with any images that are potentially important.

I'd just shoot an email to ilford and get it from the horses mouth , they're quite responsive when I've emailed them.

Challenging!

Build an insulated glove box with a heater.

Not sure it's less crazy than room temperature XP-2 slit to Minox

gbroadbridge said:

I'd just shoot an email to ilford and get it from the horses mouth , they're quite responsive when I've emailed them.

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I agree.

mshchem said:

Lomography - C-41 Development at Room Temperature With Stand Processing and Optional Bleach Bypass for Cool Effects

I love being a lab rat. And I love xpro. C-41 DIY turned me off until now because of the reports that temperature is crucial and temperature management is somewhat problematic when lacking a processor. Well, it turns out that's all irrelevant. Read on to see how you can develop C-41 similar to...

www.lomography.com

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There is just so much wrong in that article.

Not to mention the horrific colour shifts and other problems in the displayed images.
I guess if you wish to destroy the whole precept behind the design of C41, that's the way to do it.

But if you're going to scan it - it'll work out in post ... lol.

gbroadbridge said:

There is just so much wrong in that article.

Not to mention the horrific colour shifts and other problems in the displayed images.
I guess if you wish to destroy the whole precept behind the design of C41, that's the way to do it.

But if you're going to scan it - it'll work out in post ... lol.

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Yep, just a great reason to figure out how to do it at much warmer conditions with appropriate agitation

gbroadbridge said:

If you're setup with temperature controls for C41 processing, why would you try room temperature other than as an experiment?
Not something to try with any images that are potentially important.

I'd just shoot an email to ilford and get it from the horses mouth , they're quite responsive when I've emailed them.

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Yes but haven't I made the exact same points in my last post? I thought I had. However what I haven't been able to do is direct help Donald with the info he needs and so far nor has anyone else been able to, hence my suggestion that he contacts Harman
as you have done

pentaxuser.

I'd go by the extended development times given for e.g. the old Digibase C41 developer. The instruction sheet is likely still online somewhere. If needed I can look up the data when o have access to it tomorrow or so. From memory, room temperature was a development time of ca 20 minutes. Since with this film there's no color shift or crossover to be concerned with, room temperature c41 should work just fine. Base+fog level may end up a little higher but that's also survivable.

gbroadbridge said:

If you're setup with temperature controls for C41 processing, why would you try room temperature other than as an experiment?

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I'm interested because the Minox daylight loading tank doesn't lend itself well to water bath to keep the temperature at 100F, and if it works well at room temperature I can use the Minox tank without all the setup to fill and warm a water bath, warm the C-41 chemistry, etc. Not to mention the temperature and humidity levels in my darkroom when my sous vide has been holding a water bath at 100F for half or three quarters of an hour. Plus, the tiny tank and a powder chemical kit are practical to haul along on a vacation trip (doesn't even need a dark bag if I don't need to reload cassettes), where my sous vide and accompanying paraphernalia are not, even if I'm driving vs. flying.

It's been my understanding that in order to produce black image density all three color couplers (or an even broader range) need to be present in each emulsion layer of XP-2 Super, so I wouldn't expect any changes in spectral sensitivity -- unless I've misunderstood how B&W chromogenic films work in general. In fact, I see no sensible reason why the film would have more than one emulsion layer -- and the "money" argument suggests it ought to have just one, because unless it's coated on the same line as conventional color products there's no reason to have three (or more) emulsion layer coating steps.

FWIW, I have attempted the room temperature stand development from the Lomography article -- I didn't see the results as horrible, but it there was no good reason to do it that way when I was using my Flexicolor chemicals and Paterson tank anyway. I won't be using stand in this case, however. I'd be interested in the Digibase figures, though.

Donald Qualls said:

I'd be interested in the Digibase figures, though.

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I have them in a worksheet somewhere ; I'll try to think of it to look it up when I get back.

koraks said:

I have them in a worksheet somewhere ; I'll try to think of it to look it up when I get back.

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Thanks!

Aha! I found what I need here: https://www.photrio.com/forum/threads/rollei-compard-digibase-c-41-help.180465/

Looks like 77F is 7 minutes (double the standard figure), so 10:30 at 68F seems like a reasonable figure. I'll be a while before I get to test it; first I have to slit, load, and shoot a (50 exposure) roll of XP-2 Super. Hopefully before the end of the year, though.

That's the one! If you plot these times in a chart, you'll notice they drop fairly nicely on a curve that allows interpolation of additional time/temperature combinations.

This actually looks very close to the 4% per degree F (or 7% per degree C) that I've used to compensate temperature for decades. I'll double check the extrapolation, but I should be good for when I get a 120 roll slit down to 6xMinox-50, and some loaded and shot.

Years ago I made this chart; note that it includes a very doubtful (and untested) extrapolation to 15C. Temperatures are in Celsius on the horizontal axis.

Donald Qualls said:

This actually looks very close to the 4% per degree F (or 7% per degree C) that I've used to compensate temperature for decades.

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I don't think so; as you can see it's not a linear series which IMO is also to be expected since we're talking about a chemical process. Such processes often involve exponential (or logarithmic) relationships.

Is it true that bleach bypass acts as speed boost for XP2 Super? What kind of speed increase may be expected? And does the speed increase also imply much higher gamma?

If you look at the density measurements in Way Beyond Monochrome for XP2 Super iwhen developed n the regular C41 process, the true speed is 200. And this is also the true speed when developed in B&W developers. What is that bleach bypass doing that results in speed gain?

koraks said:

it's not a linear series which IMO is also to be expected since we're talking about a chemical process.

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Okay, I've used 4%/F for years, but that's over a range of about 65-80 F -- too narrow for the difference between linear and logarithmic to be significant. Looks like 21 minutes is going to be the starting point.

Raghu Kuvempunagar said:

Is it true that bleach bypass acts as speed boost for XP2 Super?

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I've been very happy shooting XP-2 Super at EI 400 in standard C-41 process (but then I get good shadow detail at box speed with Fomapan 400, which is also commonly called out as true speed 160-200). Bleach bypass approximately doubles the density for a given exposure, which is equivalent of pushing everything up by one stop -- I shoot it at 640 or 800 when I plan to bleach bypass, and (at least in 35 mm at the limit of my Epson V850) I see no change in grain. My hypothesis is that the dye image partly masks the silver grain, as would happen with the stain image from a pyro developer -- except it does so for any light source and doesn't affect contrast for multigrade printing.

Here's an example of XP-2 Super shot at EI 800 and bleach bypassed (in 35 mm):

Yeah, within a narrower temperature range a linear compensation works well, too. This is what the well-known Ilford chart is based on and I think the DigitalTruth calculator also uses this logic (IIRC it's based on the Ilford data after all).

FWIW the compensated time recommended by the cinestill instructions is much longer, 50 minutes at 22°C. But also their "normal" processing is at 39°C so maybe their stuff is just a bit slower in general.