Development times for rotary processing.

[DannyTreacy]

Hi all,

I'm using a Jobo rotary processor for my b&w 10x8 and 5x4 film, I reduce the development times by 15% during development as recommended by Jobo, this is to compensate for the constant agitation.

I wet scan the negatives and print from there. I'm very happy with the results but, like all of us, I'd like to see if better results are achievable.

So my question is - with black and white film, to achieve finer grain/perceived sharpness and greater mid tone range in development, is it better to reduce the ratio of developer to water so that the time the film spends in the developer is increased?

Also if the Jobo agitation has an effect on contrast/grain and or mid tone ranges, would it be a good idea to slow the processor's speed?

Thanks.
Danny.

[xkaes]

You'll get a lot of opinions/suggestions regarding different rotation/time/dilution/temperature/developers, etc. Whatever you choose, it's fairly straightforward to test the results yourself. You can use Kodak and/or Stouffer's wedges/step tablets or simply use a scene/setup that is typical to what you do. And remember that what you do AFTER the film development (paper, exposure, development, etc.) will also impact your results.

[Bruce Watson]

...with black and white film, to achieve finer grain/perceived sharpness and greater mid tone range in development, is it better to reduce the ratio of developer to water so that the time the film spends in the developer is increased?

If you increase dilution of a solvent developer, you are also diluting the solvent itself. This leads to less solvent action on the grain clumps which can make the clumps look somewhat sharper -- if you've got enough magnification. For example, going from 1:1 to 1:3 with XTOL and, say, Tri-X, you'll probably just be able to see the "improvement" at around 15x enlargement. Which is a whopping big print from 5x4 film. At smaller enlargement levels, there's really no visible difference. You don't have to believe me, it's very easy to make two exposures and process them differently (but to the same maximum density and therefore CI), scan them the same, make prints (or at least mid-sized prints out of the center of a full sized scan) from each scan, and view the prints side by side under the same lighting. What do you see?

If what you are really getting at is how do you optimize your film processing for scanning, there are some things you can do. However, if you are *ever* going to print the film in the darkroom, you should optimize it for darkroom printing -- it will scan just fine.

OTOH, if you are *never* going to darkroom print, you should probably look at reducing graininess and maximum density. Why? Scanning is susceptible to the Callier Effect just like optical enlarging. Smaller grain clumps help, but lower maximum density (and therefore lower CI) helps more. In my years drum scanning, I found that optimum for my workflow was a Zone VIII density value of around 1.0. This for TMY, in XTOL 1:3, in a Jobo 3010 tank, at 30 rpm (slow to increase development time to keep it comfortably above five minutes, no other reason). Such a negative is sufficiently low contrast that it would not be fun to darkroom print, but what you'll get from scanning is that you don't get so much Callier Effect highlight compression, making the digital printing process less difficult. So it's worth doing, in my book anyway.

If you haven't read Tim Vitale's paper on the structure of film and scanning, perhaps now is the time.

[DannyTreacy]

So what you're basically saying Bruce is yes dilute the ratio of developer to water and yes slow down the processor speed, right?

Thanks.

[Doremus Scudder]

Danny,

If you can simply reduce development time and keep your total time over five minutes, that is the preferred solution. Changing developer dilution to change overall negative density only really comes into consideration after you've simply reduced developing time and ended up with too-short development times.

As Bruce mentions (the point you missed, I think), developer characteristics change when you dilute them. Sometimes this is the point of diluting a specific developer. So-called "fine-grain" developers that use sodium sulfite as a silver solvent to soften grain give sharper, but more pronounced grain at higher dilutions (again, I'm just repeating what Bruce posted above). Some may want to use D-76 at 1+1 instead of straight for just this reason. Other developers are fairly dilute to begin with (think Rodinal, Pyrocat, PMK) and you may end up not having enough stock solution for the negative area you are developing if you dilute unless you increase the entire volume of developer.

Finally, finding new times for diluted developers is not always linear; you have to test. Just as you will have to test to find what the optimum developing time is for any developer for your purposes. Development times given by manufacturers are only starting points and need to be refined by the individual photographer.

Bottom line: If you need less overall contrast from your negatives, try reducing development time first. If you end up with times that are too short for even development, then you can try a different dilution, remembering that you may be changing developer characteristics, and that you must ensure you have enough stock solution for the amount of film you are developing, and that you'll have to test for the optimum time for that dilution.

Best,

Doremus

[Bruce Watson]

So what you're basically saying Bruce is yes dilute the ratio of developer to water and yes slow down the processor speed, right?

Argh... I'm not wonderful at verbal communication. If I could write I wouldn't need photography so much. Sigh....

No. What I'm saying is that if you keep all things in your workflow constant (that is, you develop your film to the same Dmax and CI), that changing dilution (of solvent developers) will make a really small change in your image quality. Changes that you may not even see until you start making prints 75 x 60 inches or bigger from 4x5 film (doesn't anybody actually print that big? I don't know anyone who does). From a practical perspective, changing dilution is mostly about controlling development time.

Changing processor speed on a rotary processor, OTOH, won't make any change to your image quality at all (again, if you keep everything else equal). All this does is effect the rate of development; if you need a longer development time, slowing your processor speed will give it to you. But that's all it does, it has no effect on image quality. You can look this up in Haist if you have a research library close by. I don't remember which volume it was in, but that's why it has an index.

If you want better image quality from a scanning-only workflow, perhaps the biggest change you can make is to develop to a lower Dmax. How low is optimum for your materials, your equipment, and your workflow has to be found by experiment. You have to do that work yourself.

What you want, for whatever process you are using, is just enough density to make it easy to print. No more.

Nothing I've said on this thread applies to color films of course. Just good ol' B&W silver negative processing.

[Bruce Watson]

Doremus,

Well said. I'm jealous of your ability to explain. I wish I were as articulate as you are.

[DannyTreacy]

Thanks for the replies, I think that I have grasped it based on:

If you can simply reduce development time and keep your total time over five minutes, that is the preferred solution. Changing developer dilution to change overall negative density only really comes into consideration after you've simply reduced developing time and ended up with too-short development times.

Bottom line: If you need less overall contrast from your negatives, try reducing development time first. If you end up with times that are too short for even development, then you can try a different dilution, remembering that you may be changing developer characteristics, and that you must ensure you have enough stock solution for the amount of film you are developing, and that you'll have to test for the optimum time for that dilution.

My development time right now for Ilford HP5 in Ilfosol 3 in the Jobo is 5.5 mins. That's with a 1:9 developer dilution. The times were as recommended by the digital truth database rather than Ilford I think.

There was data for development of 1:14, is this just for saving the chemistry then?

Thanks!

[DannyTreacy]

Argh... I'm not wonderful at verbal communication. If I could write I wouldn't need photography so much. Sigh....

No. What I'm saying is that if you keep all things in your workflow constant (that is, you develop your film to the same Dmax and CI), that changing dilution (of solvent developers) will make a really small change in your image quality. Changes that you may not even see until you start making prints 75 x 60 inches or bigger from 4x5 film (doesn't anybody actually print that big? I don't know anyone who does). From a practical perspective, changing dilution is mostly about controlling development time.

Changing processor speed on a rotary processor, OTOH, won't make any change to your image quality at all (again, if you keep everything else equal). All this does is effect the rate of development; if you need a longer development time, slowing your processor speed will give it to you. But that's all it does, it has no effect on image quality. You can look this up in Haist if you have a research library close by. I don't remember which volume it was in, but that's why it has an index.

If you want better image quality from a scanning-only workflow, perhaps the biggest change you can make is to develop to a lower Dmax. How low is optimum for your materials, your equipment, and your workflow has to be found by experiment. You have to do that work yourself.

What you want, for whatever process you are using, is just enough density to make it easy to print. No more.

Nothing I've said on this thread applies to color films of course. Just good ol' B&W silver negative processing.

Thanks for the info Bruce, I actually print my 10x8 at 85" x 70" so it would be great to get the best possible resolution out of it.

Home processing is new to me as I used to go to labs but I got tired of having to deal with dirty negatives due to poor workmanship.

[cowanw]

If it helps, I presoak my films for 5 minutes in water; I like to see the blue black dye come out. I use 1:14 and seven minutes for development with HP5 in Ilfosol 3 in a JOBO.

Thanks for the replies, I think that I have grasped it based on:

My development time right now for Ilford HP5 in Ilfosol 3 in the Jobo is 5.5 mins. That's with a 1:9 developer dilution. The times were as recommended by the digital truth database rather than Ilford I think.

There was data for development of 1:14, is this just for saving the chemistry then?

Thanks!