Question about several development times for the same exposure

I have never done any alternative process. But I want a scene (negative) available just in case for my future. I don't want to make a digital negative.
Next Friday 22nd I'll give a talk at a museum, and I asked a friend to do a portrait of me, a couple of hours before the event, so, by 2-3 PM.
I asked him to do the same exposure 12 times (medium format): I'll be standing next to a wall with a 7 feet tall print of a diagram with text (from my second book) that's there to be read by students and teachers while I explain it. I think I'll use my Hasselblad's 50mm instead of the normal lens, as I need that wider coverage and also that type of DOF, requiring both my face and the wall's text sharp, without using a tripod. I'll use natural light (inner yard corridor wall) but just a few stops below common outdoors light. I guess I'll have to uprate my film slightly: no problem at all for flat light.
I will use HP5+. I have TMX too, but it's too slow for this IMO, and I've also read it's not an optimal film for some alternative processes. I know ISO400 isn't optimal either, but I just can't buy other films or carry a tripod. I'm sorry: I won't use a staining developer, as I love grain, and yes, I know -only superficially, of course- about UV light use and stain advantages. I know purists wouldn't do things the way I plan to do them, but I'll pay to see. I have Perceptol, Rodinal, D-76, HC-110, FX-39 and Microphen. I think the last one is the best option in this case.
I plan cutting the strip in four pieces, and do four development times: the shortest one for (silver paper with) my condensor enlarger, two more in the middle, and the longest one will be twice the time for a diffussion enlarger, what's often recommended for salt prints.
Thanks for all comments and recommendations on the way you'd do it.

It's still not clear to me what you're going to do with the negatives. Are they indeed for enlarging (condensor / diffuser) and salt printing? If so, I'd do two strips and call it a day...
Or better yet, do 4 strips and develop 1 for enlargement (diffuser and condensor can easily use the same strip of course...) and the other 3 with substantially longer times and/or higher concentrations so that you're fairly sure to end up with at least one that will make a decent salt print.

How I'd really do it, is shoot it on sheet film, but that would violate several of the limitations you mentioned so let's not go there.

So, again: what's the purpose / end result of the exercise?

PS pretty much any of the developers will be fine for making salt print negatives. No stain is needed.
PPS while HP5+ will work for making salt print negatives, it's just about the poorest choice.

How are you going to cut the 120 film into different frames before development? You'll have no way of knowing where the frame lines are. Short of getting *very* creative, you should plan to use a whole roll for each developer/time combo, or re-spool a smaller length of film if you're really worried about cost.

Koraks,
I want to have the same scene available for different processes in the future. No idea how many of them I'll try...
If any expert says four development times are few for covering a broad but not too abrupt contrast range, I could use two rolls for 8 different degrees of max. density...

jonmon6691 said:

How are you going to cut the 120 film into different frames before development? You'll have no way of knowing where the frame lines are. Short of getting *very* creative, you should plan to use a whole roll for each developer/time combo, or re-spool a smaller length of film if you're really worried about cost.

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Jon, I use a lot more developer than what's used in an exhaustion dilution, so I can develop one fourth of a 120 film with confidence: results are from all practical points of view the same thing my film callibrations already set.
Film and developers are cheap.
It doesn't matter which frame I cut: they're all identical.

Juan Valdenebro said:

Koraks,
I want to have the same scene available for different processes in the future. No idea how many of them I'll try...
If any expert says four development times are few for covering a broad but not too abrupt contrast range, I could use two rolls for 8 different degrees of max. density...

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Ok, gotcha. In that case perhaps 2 rolls would be nice to have and then just develop for any contrast ranging from classic cyanotype (cf. something like grade 4 on VC paper) all the way to salted paper and New Cyanotype (about a grade beyond grade 00). Without knowing beforehand which processes you'll print these with it'll be impossible to get a perfect match, but if you have 4 to 8 different curve lengths you should be good.

A slight drawback of your approach is that some processes benefit from specific attention to the toe of the curve. For instance salted paper does just fine in a linear fashion and due to its long scale --> strong development, I would prefer to shoot HP5+ at close to 800, whereas for Van Dyke Brown with its dramatic S-curve exposure at 200 or so would be more appropriate. So there's always going to be compromises if you fire off 12 to 24 shots in an identical way, but for illustration purposes you'll probably be close enough.

koraks said:

It's still not clear to me what you're going to do with the negatives. Are they indeed for enlarging (condensor / diffuser) and salt printing? If so, I'd do two strips and call it a day...
Or better yet, do 4 strips and develop 1 for enlargement (diffuser and condensor can easily use the same strip of course...) and the other 3 with substantially longer times and/or higher concentrations so that you're fairly sure to end up with at least one that will make a decent salt print.

How I'd really do it, is shoot it on sheet film, but that would violate several of the limitations you mentioned so let's not go there.

So, again: what's the purpose / end result of the exercise?

PS pretty much any of the developers will be fine for making salt print negatives. No stain is needed.
PPS while HP5+ will work for making salt print negatives, it's just about the poorest choice.

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I see no limitations, and I don't think my LF camera would be superior to my Hasselblad in this particular case.
Now, if you were doing what I talked about (say with your sheets), would you do it from condensor density to twice diffusion times?
Would you do four times, or how many?

Oh, you just answered, thanks, let me read that.

koraks said:

Ok, gotcha. In that case perhaps 2 rolls would be nice to have and then just develop for any contrast ranging from classic cyanotype (cf. something like grade 4 on VC paper) all the way to salted paper and New Cyanotype (about a grade beyond grade 00). Without knowing beforehand which processes you'll print these with it'll be impossible to get a perfect match, but if you have 4 to 8 different curve lengths you should be good.

A slight drawback of your approach is that some processes benefit from specific attention to the toe of the curve. For instance salted paper does just fine in a linear fashion and due to its long scale --> strong development, I would prefer to shoot HP5+ at close to 800, whereas for Van Dyke Brown with its dramatic S-curve exposure at 200 or so would be more appropriate. So there's always going to be compromises if you fire off 12 to 24 shots in an identical way, but for illustration purposes you'll probably be close enough.

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That's a great amount of information, Koraks, thanks a lot!

Juan Valdenebro said:

I'll be standing next to a wall with a 7 feet tall print of a diagram with text (from my second book) that's there to be read by students and teachers while I explain it.

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I was unable to find your books with a Google search. Can you provide a link to someplace that describes your books and through which I can purchase one or both of them?

I think what you say makes more sense... I'll do two rolls doing a bracketing of 5 frames, two blank ones, and the same bracketing again. (Half stops from 200 to 800).
And I'll do 4 development times: condensor, and then 40% more time than the previous one, for the remaining three.
Thanks again.

Determine the LER for each of the printing methods.

Desired LER / log subject Luminance range - flare = CI

Thank you, Stephen.
For sure that's a great way to master each process...
For now, I'll do my experiment, finally, with four strips of 5 frames, not by half stops as I said, but at 200-400-800-1600-3200, much better for a broader range...
That would be kind of OK for a just in case situation, wouldn't it? Even if not perfect, I think those four strips will be helpful for a first approach to at least a few alternative processes.
I reconsidered one more thing: just adding time wouldn't work well... I think two of the strips in Microphen 1+1, and the other two in Microphen stock, from reduced to every minute agitation, can produce four very different and useful density levels.
Then, in the future, I know I should follow your advice for serious work. Thank you!

@Juan Valdenebro Silver Gelatin enlarging is flexible and can tolerate some development error with multigrade filtration, but the alt processes that you imagine probably need a fairly good match… or at least a bit of allowance of variation.

With that thought, you may want to make one compromise development just over 0.6 contrast for enlarging, and then aim just one or two different times for alt processes. Develop the heck out of them, they want high contrast negatives.

For anyone interested, run a family of curves (5 or 6), obtain the gradients, and plot them on a Gradient / time curve.

Find the LERs:
Condenser enlarger on silver grade 2: 0.80
0.80/1.80 = 0.44

Diffusion enlarger on silver grade 2: 1.05
1.05/1.80 = 0.58

Platinum: 1.60
1.60/1.80 = 0.88

Those are the only ones that come to mind, but with a little research, I'm sure the LER information for each alternative printing process is out there.

Juan Valdenebro said:

at 200-400-800-1600-3200

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Sounds like a lot of work, so it's not what I'd do, since I'm phenomenally lazy
Seriously though, I think 200, 400 and 800 would suffice. From the perspective of the printing process there's no benefit in also adding 1600 and 3200. They'll just cut shadow detail regardless of how those negatives will be printed.

Bill Burk said:

they want high contrast negatives.

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Most, but not all. Regular cyanotype requires low contrast negatives, and depending on pigment loading gum bichromate also doesn't necessarily require very high contrast either. And Van Dyke Brown works best with negatives that are kind of hard but still well within VC printing range (a good VDB negative prints nicely on something like grade 1.5 IME).

Juan Valdenebro said:

useful density levels.

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Think in terms of contrast, or as @Stephen Benskin implies, gamma. Overall density isn't useful and mostly detrimental. You want to tailor the gamma of your negatives to the process. So doing a long series of exposures and only two different development approaches will not give what you want. Flip it around; only make 2 or at most 3 exposures, but do at least 3 different developments on those. You could eliminate some of the less logical combinations to cut down the job to a manageable size. For instance 1 stop underexposed and soft development is not a meaningful combination with your purpose in mind, so can be left out.

For clarity, I mean something like this. Note: this is an off-the-cuff example only; you could improve it (lots) by including Stephen's suggestions into it:

Every box that remains empty even after study of all processes relevant to you can be left out; apparently those combinations aren't needed. The two top left certainly look that way; I can think of no process that requires those. In some places you could economize; for instance, the bottom row you could also combine (leave out the 800 and 200 exposures and just stick with the 400) because all those processes will be able to make a decent print on a normally exposed negative that's developed to a sufficiently high contrast. Sure, a salted paper negative will need to be just a smidgeon less contrasty than the ideal negative for New Cyanotype, but the difference is small enough to get away with it for an illustration in a book, I think. And of course carbon transfer can be tailored to suit just about any negative.
By approaching it like this I think you could work out a minimum number of exposure/development combinations that are very close to ideal without giving you years of work. You can also consciously decide where you want to cut corners or, to the opposite, hedge yourself against unforeseen eventualities.

koraks of course the high contrast processes need flat negatives or halftone screens unless you want graphic effects. I completely forgot about cyanotype, gum bichromate, lith and photogravure.

Your graph is very thoughtful and can be helpful with some more detail and experiment results.

Bill Burk said:

photogravure

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Well, that one is a special case altogether and I left it out because it needs a positive. Otherwise it's essentially a carbon transfer print if you do it the old-fashioned way (so perhaps it needs quite a long curve?) or you could use polymer (which I did for a brief while) in which case it needs a rather soft positive, indeed.

I don't know about stone lithography; never done it and I'd have to look it up. Perhaps....one day...?