How to develop for inbetween ISO values that i cant find on Massive Dev?

Hey all,

I want to shoot some HP5 at 160 but on the massive dev chart i can only find HC110 times for ISO 100 (pulled 2 stops) and 200 (Pulled 1 stop). at 160 its pulled 1 and 1/3 stops. Anyone know how i calculate the dev times?

I'm not sure I can see the difference one third of a stop makes; I think I'd just expose and develop for 200.

However, if I had to use 160, I think I'd interpolate like this. Plot a graph with film speed on the x-axis, and the recommended development time on the y-axis. I'd use Excel because that's what I have. You could do it on a calculator with a graphical display, or even by hand on squared paper. I think the graph will be easier if you either plot the x on a logarithmic scale, or convert the ISO number to DIN (so one stop is an increase of three, not a doubling of the number). You have at least three points (times recommended at ISO 100, 200 and 400). Draw a smooth curve through them, and read off the time for any intermediate speed you like.

Since developing times don't actually change the baked-in speed of a film, it's the subject contrast that's important here.

 

If the subject has a higher than normal contrast (brightness range), then pull the developing. If not, expose and develop it normally and deal with any overexposure in printing or scanning.

 

Plus, surely it doesn't take much figuring to come up with a time slightly shorter than that given for 200 EI and not as short as for 100 EI? It's B&W film for goodness sake, with a latitude as wide as a barn door!

I'm not sure I can see the difference one third of a stop makes; I think I'd just expose and develop for 200.

However, if I had to use 160, I think I'd interpolate like this. Plot a graph with film speed on the x-axis, and the recommended development time on the y-axis. I'd use Excel because that's what I have. You could do it on a calculator with a graphical display, or even by hand on squared paper. I think the graph will be easier if you either plot the x on a logarithmic scale, or convert the ISO number to DIN (so one stop is an increase of three, not a doubling of the number). You have at least three points (times recommended at ISO 100, 200 and 400). Draw a smooth curve through them, and read off the time for any intermediate speed you like.

 

Cheers Dustin

Since developing times don't actually change the baked-in speed of a film, it's the subject contrast that's important here.

 

If the subject has a higher than normal contrast (brightness range), then pull the developing. If not, expose and develop it normally and deal with any overexposure in printing or scanning.

 

Plus, surely it doesn't take much figuring to come up with a time slightly shorter than that given for 200 EI and not as short as for 100 EI? It's B&W film for goodness sake, with a latitude as wide as a barn door!

 

thanks Joe

Any particular reason why 160?

 

As said, this is a film with a lot of lattitude, and "pulling" is going to decrease the contrast (not always a bad thing with HP5). If you're striving for exposure as close to absolutely perfect as possible, use an EI for which you have a time. Otherwise, just go close enough, or extrapolate for some time between the two values.

 

This is a different film, and going in the opposite direction, but I feel compelled to mention that the massive dev chart gives a good portion of the dev times for FP4+(ASA 125) as being good for "125-200".

You won't see a difference between 160 and 200. But, if you want, use about 75% of the difference between 100 and 200.

 

If 100 is 4 minutes and 200 is 5 minutes, use 4:45 . . .

I'm not sure I can see the difference one third of a stop makes

 

Is right. There is a flaw called misplaced concreteness - in this case, you are trying to be too precise in a situation where there are myriad other uncontrolled variables.

 

In the ballpark is good enough for most ordinary efforts.

Sweating out a 1/3 stop difference with B&W film isn't worth the effort. I would be surprised if the shutter speeds and aperture settings of an older film camera (is there any other kind by now?) weren't off by almost that amount in some direction or other, and you wouldn't know that without a lot of equipment testing. The change in contrast or density should be easily fixable in either wet printing or scanning.

I would be surprised if the shutter speeds and aperture settings of an older film camera (is there any other kind by now?) weren't off by almost that amount in some direction or other, and you wouldn't know that without a lot of equipment testing.

 

Late high end Nikons(notably the F5, but I'd expect the same on the F6) claim a "self testing" and "self correcting" shutter. I wouldn't be surprised if the cameras that competed with the F5 had the same feature.

 

At least on Nikons, too, I tend to trust the PRECISION(repeatability/consistency) of the aperture more when set from a ring on the lens as opposed to setting it from the body. There again, the F5, F6, and F100 all give you the option of doing it either way with lenses that have an aperture ring. Still, though, even if they are consistent, that doesn't mean that they are what they say they are.

 

I know that there's some shutter speed scatter on my various F2s-at their "best" speeds the standard deviation might amount to 1/6 stop, while 1/3 stop is more typical across the range, especially for one with an unknown service history. Lately I've been shooting a decent amount of Velvia in an F2SB from the mid-1970s, and I'm happy with how the transparencies look. BTW, aside from variation in shutter speeds, there are also variations in the meter reading, although the DP-3/DP-12 are probably a bit more stable/dependable than a DP-1/DP-11. That's a film that's a lot pickier about exposure than HP5+.

Late high end Nikons(notably the F5, but I'd expect the same on the F6) claim a "self testing" and "self correcting" shutter. I wouldn't be surprised if the cameras that competed with the F5 had the same feature.

 

At least on Nikons, too, I tend to trust the PRECISION(repeatability/consistency) of the aperture more when set from a ring on the lens as opposed to setting it from the body. There again, the F5, F6, and F100 all give you the option of doing it either way with lenses that have an aperture ring. Still, though, even if they are consistent, that doesn't mean that they are what they say they are.

 

I know that there's some shutter speed scatter on my various F2s-at their "best" speeds the standard deviation might amount to 1/6 stop, while 1/3 stop is more typical across the range, especially for one with an unknown service history. Lately I've been shooting a decent amount of Velvia in an F2SB from the mid-1970s, and I'm happy with how the transparencies look. BTW, aside from variation in shutter speeds, there are also variations in the meter reading, although the DP-3/DP-12 are probably a bit more stable/dependable than a DP-1/DP-11. That's a film that's a lot pickier about exposure than HP5+.

@ben--I was thinking more of classic mechanical shutter cameras than more recent electronically controlled high end pro Nikons or Canons. If I remember correctly, it used to be a big deal that Leicas left the factory with shutter speeds that were within 10% of marked speeds, a much better performance than many mechanical focal plane shutters at the time.

Recommended developing times and temperatures for specific film/developer combinations (like on manufacturers websites and Massive Development Chart) are intended as starting points for developing. For example, some users might very well have a shorter processing time for E.I. 160 than another user might have for same combo rated at E.I. 200.

A number of years back I contributed times to Massive Development Chart for Eastman 5222 for D-76, HC110, and Rodinal and even though I determined these times through experimentation I still only regard those times as a starting point.

Also, the times in charts are usually rounded, maybe to a whole or half minute.

 

For black and white or color negatives, round to the nearest whole stop.

 

I have never seen intermediate push values for reversal film, but I suspect one could

interpolate the values if needed.

Hey all,

I want to shoot some HP5 at 160 but on the massive dev chart i can only find HC110 times for ISO 100 (pulled 2 stops) and 200 (Pulled 1 stop). at 160 its pulled 1 and 1/3 stops. Anyone know how i calculate the dev times?

There's an app for calculating the dev times of in between values: https://play.google.com/store/apps/details?id=photography.darkroom.pro

If you do an exposure test, most B&W films show very little difference with an entire stop difference in exposure, especially overexposure.

 

Same goes for adding or subtracting a few seconds to/from the development time. After all, it takes several seconds to fill and empty most tanks, and another few seconds to arrest development in a rinse or stop bath.

 

Fretting and piffling about over 1/3rd of a stop is completely pointless, misplaced and a waste of time.

 

(snip)

Same goes for adding or subtracting a few seconds to/from the development time. After all, it takes several seconds to fill and empty most tanks, and another few seconds to arrest development in a rinse or stop bath.

 

(snip)

 

I never thought much about this, until I did E6 (about 40 years ago).

 

You are supposed to time from when you start pouring in one step, until you start pouring the following step.

(But I agree, mostly don't worry about it for black and white.) Start pouring out about 15s early.

 

As the tank fills, it will start developing from the bottom first, and also stop (when the next step goes in)

from the bottom first. Much of the fill time should cancel out.

Personally I'd just use simple interpolation due to film latitude.

The times Kodak gives for Tri-X are not different for push zero and one stop.

 

But even more, the OP asks for pull times, with no explanation why pull times.

 

Since negative films have more latitude for overexposure than underexposure,

many people will increase exposure half to one stop, unless the scene has

especially high contrast.

 

Many films have a contrast vs. development time graph on the data sheet.

It the OP wants that, he should say so.

I'm with SCL - interpolate, and then rely on variable contrast paper and your printing skills to compensate for any imperfections.

 

But if you insist on making it rocket science, you can do a film developing speed test to calibrate your process to the chosen EI. But when you do that, make sure that you understand that the results only apply if you have the same film emulsion number - if you come back a year later with a different emulsion batch, the results could be different.

 

The Massive Development Chart is only a guide, and at best it should be considered as a source of a starting point. Your personal darkroom practices will result in variations.