Rollei RPX 25 @ 400 developing adjustment

Laci Toth · Jan 21, 2020

Hello all,

I’ve run out of films today while I was out taking photos, I consumed 3 rolls and only two films left a Washi W and a Rollei RPX 25. I chose the latter but as there wasn’t sufficient light I pushed it to 400. I prefered more this decision than avoiding taking photos at all, a bit of experimenting can do good.
I’m wondering if there’s a rule of thumb for development times when pushing films? I couldn’t find any info not even for pushing this film by one stop.

koraks · Jan 21, 2020

The rule of thumb goes something like add 25% (20-30) of development time per stop push. Of course, a push of 25 film to 400 is borderline hopeless and no matter what you do with it, you'll only get the highlights and some of the upper midtones in the image in the best case.

Laci Toth said:
I couldn’t find any info not even for pushing this film by one stop.

Slow-speed films aren't very popular for pushing, for obvious reasons. Given the high-contrast nature of RPX25, I wouldn't hold much hope for even a 2 stop push, let alone a 4 stop push.

rubbernglue · Jan 21, 2020

I would develop it as 800 (at least).

Laci Toth · Jan 21, 2020

koraks said:
The rule of thumb goes something like add 25% (20-30) of development time per stop push. Of course, a push of 25 film to 400 is borderline hopeless and no matter what you do with it, you'll only get the highlights and some of the upper midtones in the image in the best case.

Slow-speed films aren't very popular for pushing, for obvious reasons. Given the high-contrast nature of RPX25, I wouldn't hold much hope for even a 2 stop push, let alone a 4 stop push.

Thanks for your response!
Yes, I’m aware that it might be only silhouettes, but still I could get something instead of nothing and interesting results.
Will try the 25% and see what will be the outcome.

koraks · Jan 21, 2020

Keep in mind it's something like 25% per stop. So 4 stops push would be a multiplication factor of about 2.5x. So if your development time is listed for ISO 25 as e.g. 10 minutes, try something like 25 minutes.
However, with this kind of extreme push, such multiplication doesn't make much sense anymore. It'll just push the highlights into oblivion while what would normally be shadows and midtones remain pitch black no matter what you do.

You'll probably get some sort of image. It'll be poor by any measure, but it may be recognizable.

Laci Toth · Jan 21, 2020

rubbernglue said:
I would develop it as 800 (at least).

Or develop it at box speed and send them the negs and claim a refund. =D

MattKing · Jan 21, 2020

I'm going to suggest something that no one who is familiar with my thousands of posts here will believe came from me - I would suggest that you try stand development with this film.

I don't think that it will result in anything useful whatever you do - a four stop under-exposure with a film like this is not likely to give you much at all - but it would probably be a more useful experiment than trying to save the film by increasing its contrast (which is all you are really doing with a push process).
I'm not the one to ask about how to do this - the stand development fans are better for that.

koraks · Jan 21, 2020

I considered that too. I'm not a fan of stand development myself, but in this particular case, I'm sure it won't hurt (not sure of it'll help either, but hey...)

Rudeofus · Jan 21, 2020

Laci Toth said:
Or develop it at box speed and send them the negs and claim a refund. =D

The frame rebates would prove inadequate exposure ---> no refund.

There are some articles and blogs about Rollei RPX 25, and e.g. this one shows, what images shot at EI 6/12/25/50/100/200 look like. You see noticeable degradation at EI200 and should expect yet deeper shadows at EI400. If you follow Matt's advice of stand development: typical run-off-the-mill stand development in Rodinal has been shown to be γmax development, i.e. anything, which saw even faint effective exposure, will be fully developed. It's basically optimal speed with lots of grain. Note, that optimum speed still means only ISO50, since that was reported to be real ISO rating of this film, maybe a tad higher if you hit the shadow regions really hard with stand development.

Laci Toth · Jan 21, 2020

Rudeofus said:
The frame rebates would prove inadequate exposure ---> no refund.

There are some articles and blogs about Rollei RPX 25, and e.g. this one shows, what images shot at EI 6/12/25/50/100/200 look like. You see noticeable degradation at EI200 and should expect yet deeper shadows at EI400. If you follow Matt's advice of stand development: typical run-off-the-mill stand development in Rodinal has been shown to be γmax development, i.e. anything, which saw even faint effective exposure, will be fully developed. It's basically optimal speed with lots of grain. Note, that optimum speed still means only ISO50, since that was reported to be real ISO rating of this film, maybe a tad higher if you hit the shadow regions really hard with stand development.

I might try the stand dev. I’ve never ever done it before so why not.

Bill Burk · Jan 21, 2020

I’ll also second MattKing. But! Listen to jnantz too. Develop this film overnight.

There will be nothing on it unless you do something extreme.

Now I would at least develop an hour in stock Dektol.

But I also think you could rewind it and put it back in the camera. You haven’t exposed the film yet.

I understand wanting to keep going despite the wrong film for the occasion. But I would have shot the film at it’s rated speed “even if” that meant very long exposures and everything is blurry.

Rudeofus · Jan 22, 2020

Bill Burk said:
Now I would at least develop an hour in stock Dektol.

Have you tried this? Dektol is a very active developer, which may well cause this film to fog after an hour.

@Laci Toth : how motivated and experienced are you as tester and homebrewer? These images seem to be very important to you, given that you shot them anyway under very adverse conditions. Would you be willing to sacrifice another roll of Roller RPX 25 to do some tests before you run the actual roll?

baachitraka · Jan 22, 2020

fs999 · Jan 22, 2020

Rudeofus said:
this one shows, what images shot at EI 6/12/25/50/100/200 look like.

The contact sheet was optimized for ISO 25...

Rudeofus · Jan 22, 2020

fs999 said:
The contact sheet was optimized for ISO 25...

Correct, but missing shadows are missing shadows at any brightness level.

rubbernglue · Jan 22, 2020

Why not cut the film in half and develop it two ways

pentaxuser · Jan 22, 2020

Bill Burk said:
But I also think you could rewind it and put it back in the camera. You haven’t exposed the film yet.

Bill will it really be the case that as he has exposed it but at 4 stops under there will be nothing there at all. No latent image of any kind that would show up and spoil the correctly exposed frames if he were to rewind and expose again?

Thanks

pentaxuser

Laci Toth · Jan 22, 2020

Bill Burk said:
I’ll also second MattKing. But! Listen to jnantz too. Develop this film overnight.

There will be nothing on it unless you do something extreme.

Now I would at least develop an hour in stock Dektol.

But I also think you could rewind it and put it back in the camera. You haven’t exposed the film yet.

I understand wanting to keep going despite the wrong film for the occasion. But I would have shot the film at it’s rated speed “even if” that meant very long exposures and everything is blurry.

Good point, thanks! I mean to shot it at the rated speed even if it’s blurry, still can get great photos.

Laci Toth · Jan 22, 2020

Rudeofus said:
Have you tried this? Dektol is a very active developer, which may well cause this film to fog after an hour.

@Laci Toth : how motivated and experienced are you as tester and homebrewer? These images seem to be very important to you, given that you shot them anyway under very adverse conditions. Would you be willing to sacrifice another roll of Roller RPX 25 to do some tests before you run the actual roll?

Yea, good idea but I’ve already shot it at that speed and probably I’m gonna get only silhouettes anyway.

Laci Toth · Jan 22, 2020

rubbernglue said:
Why not cut the film in half and develop it two ways

I rather ask the film to just be great and develop itself and let me know when it thinks there’s some usable result.

pentaxuser · Jan 22, 2020

Laci Toth said:
I rather ask the film to just be great and develop itself and let me know when it thinks there’s some usable result.

I applaud that sentiment. I'd say that demonstrates more faith in the inherent good nature of film than maybe even Henning Serger has

pentaxuser

Bill Burk · Jan 22, 2020

Rudeofus,

That contact sheet does show something will appear!

When I develop film normally, I use D-76 1:1 for about 13 minutes. If I had to develop 4 stops underexposed I would develop for 45 minutes in D-76 straight.

So I think it might work to double the concentration and triple the time.

Laci Toth · Jan 23, 2020

Bill Burk said:
Rudeofus,

That contact sheet does show something will appear!

When I develop film normally, I use D-76 1:1 for about 13 minutes. If I had to develop 4 stops underexposed I would develop for 45 minutes in D-76 straight.

So I think it might work to double the concentration and triple the time.

Thank you for your suggestion! I might give this a go.

Richard Searle · Jan 23, 2020

I've done something similar taking town's Christmas decorations, shop windows etc at dusk. Exposed Rollei Ortho 25 plus, ignored metering and exposed at f2.8 1/30 sec. Developed in D-19 1+2 for 15 minutes. Agitation was continuous for 1st minute, then every 30 secs. And I got images on the film. Not printed yet. If I didn't have D-19 available I would have used D-72 1+9 for 10 minutes. I don't think stand development is the way to go, unless you can develop by inspection like Bert Hardy did.

pentaxuser · Jan 23, 2020

Laci Toth said:
Thank you for your suggestion! I might give this a go.

Whatever you decide to do Laci I hope you will let us know and show the results. It is the only way we expand our boundaries of knowledge Thanks

pentaxuser

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