Evaluating negative density range by contact printing on silver paper.

Philipp Grewenbach · Dec 29, 2020

Hello,

I have just recently started my journey into alt-processes, and one thing I find rather difficult is assesing negative density range for certain processes. I know what density ranges I need for cyanotype or carbon, but I find it difficult to see if my negatives are good enough. As I do not have a densitometer, I had an idea, and don't know if any of you did this, but wanted to ask if it should work:

I found a table with paper and negative ranges for different contrast grades of Multigrade Paper.
For example the paper at grade 1 has a density range between 1.15 and 1.4, and at grade 0 it has a range between 1.4 and 1.7, according to this table.

So my idea was, that if I contact print my negative onto a sheet of Multigrade Paper, using light from the enlarger with grade 0 filter, and the image has good contrast and goes from all-black to all-white, then this same negative should also work very well for carbon transfer and even pt/pd prints...

Has any of you tried something like this, and do you know if it should work, or have I made a mistake in my thinking?

Thanks for any responses!

Lachlan Young · Dec 29, 2020

Philipp Grewenbach said:
For example the paper at grade 1 has a density range between 1.15 and 1.4, and at grade 0 it has a range between 1.4 and 1.7, according to this table.

That's the theory - but in practice there can be quite wide variance between different products - compare Ilford's MG Cooltone FB and Warmtone FB - officially an exposure through a Grade 0 filter on cooltone equates to a DR of 1.15 and on warmtone to 1.6. Bit of a difference! Even at 00 on Cooltone, you're only getting 1.3. The other thing to watch out for is that the 00 curve behaviour in the shoulder on some papers (thus affecting shadows in the print) is less linear than at higher grades.

osella · Dec 29, 2020

I’ve done this but only as a “contact sheet” to proof the negatives. It should give you a relative idea of the density range, but not really the tonal distribution. I only print Pd/Pt without any restrainer so I’m not sure about carbon or cyanotype.

In my case pure black to pure white in a print is a density range of 2.25 so I can’t really reproduce that with multigrade paper. But you can still make a nice print without using the whole tonal range.

radiant · Jan 4, 2021

No intention to hijack this thread, but a question about negatives for alternative processes.

Any tips how to expose & develop film negatives for alternative processes; how to make negatives "long"? I'm using Foma 100 and probably trying salt print as first try.

koraks · Jan 4, 2021

vedostuu said:
Any tips how to expose & develop film negatives for alternative processes;

Depends a lot on the process! On one extreme, there's (classic) cyanotype which requires rather thin negatives; ones that would print nicely on about grade 4 paper. On the other end, there's salted paper, which requires negatives that print well on grade 00 or not even that.

Foma 100 for salted paper is easy; just use twice the developer concentration OR twice the development time for a decent starting point. So if you use e.g. pyrocat and normally develop for 10 minutes at 1+1+100, I'd go for 1+1+50 and 10 minutes. Or if you normally use D76 1+1 for 10 minutes, give 1+0 a try at the same time or keep using 1+1 but develop 20 minutes instead. It's not an exact science done this way, but it'll get you in the ballpark for sure.
With some developers, you may want to prefer increasing concentration rather than extending development time as you can run into oxidation problems with longer times. Pyrocat (and other staining developers) and rodinal come to mind, for instance.
Also good news: any developer will work. I've done excellent negatives for salted paper in....XTOL - which is sometimes said to be soft, or even bland. No worries - contrast through the roof...

radiant · Jan 4, 2021

koraks said:
Also good news: any developer will work. I've done excellent negatives for salted paper in....XTOL - which is sometimes said to be soft, or even bland. No worries - contrast through the roof...

Thanks koraks for the tips! I didn't know cyano wants thin negatives :O - good to know!

Maybe I try 1+25 Rodinal for twice the time (8 minutes). What about exposure, should I expose more too?

Longer development: density of highlights grow.
More exposure: density of shadows grow.

Well, actually if I do both then the "contrast" gets lower. Or does it.. Uhm, this is still hard

I read from some thread here (cannot find it anymore) that the plan is not to increase contrast but to make the negative "long" - having wide tonal range but also having maximum density difference. So not only make contrasty negatives but have the tones spread well. I guess I need to have high SBR scene too!

Lachlan Young · Jan 4, 2021

vedostuu said:
Thanks koraks for the tips! I didn't know cyano wants thin negatives :O - good to know!

Maybe I try 1+25 Rodinal for twice the time (8 minutes). What about exposure, should I expose more too?

Longer development: density of highlights grow.
More exposure: density of shadows grow.

Well, actually if I do both then the "contrast" gets lower. Or does it.. Uhm, this is still hard

I read from some thread here (cannot find it anymore) that the plan is not to increase contrast but to make the negative "long" - having wide tonal range but also having maximum density difference. So not only make contrasty negatives but have the tones spread well. I guess I need to have high SBR scene too!

As you develop to a higher CI, your effective EI can grow slightly - with a self masking/ printing-out process, you can get away with what seem to be thinner shadows, as long as your highlights are dense enough.

As Koraks says, most normal neg developers are quite capable of delivering long scale negs - and if not, universal developers (PQ Universal for example) can boost things nicely - and with lower fog.

Which reminds me, I need to do some more tests in the (mis)use of PQ Universal for Ralph Gibson type negs...

ProfessorC1983 · Jan 4, 2021

It's also worth mentioning that with staining developers (e.g. Pyrocat-HD) you get an effective boost in print contrast since the stain blocks more UV than visible light -- see Sandy King's article for more info and test data: https://sandykingphotography.com/resources/technical-writing/pyro-staining-developers

I find that Pyro-HD lets me develop negs around DR 1.5-1.8 that print more or less equally well on Grade 0/00 silver paper as well as alt processes like VDB and salt, assuming an appropriate scene brightness range. Whereas the less contrasty ones that end up around DR 0.9-1.2 are appropriate for either Grade 2/3 or classic cynanotype.

koraks · Jan 4, 2021

Lachlan Young said:
As you develop to a higher CI, your effective EI can grow slightly - with a self masking/ printing-out process, you can get away with what seem to be thinner shadows, as long as your highlights are dense enough.

Yes, that is exactly my experience. Feel free to rate your film about half a stop faster. In fact, I prefer to do this to keep peinting times manageable as otherwise the shadows get a bit dense (on the negative) to my liking.

ProfessorC1983 said:
like VDB and salt

Salt requires a bit more contrast in my experience than VDB. For me, a good VdB negative prints well on grade 0, while a good salt negative doesn't quite print well on grade 00. Also VdB benefits from more shadow separation so I prefer to overexpose negatives for this process by up to a stop, while I underexposed them by half a stop for salt. VdB has a very pronounced s-curve while salt is much more linear. They're quite different animals in my experience.

radiant · Jan 5, 2021

I tested Foma 100 on Rodinal 1+25 8 minutes. Exposure was a bit sketchy since I was on reprocity side but I think exposure was somehow correct. (6 seconds -> 36 seconds)

I don't have good densitometer so I just calculated minimums and maximums of the density and I got about 7.5 stops, log10 = 2.1.

Is there any way to approximate CI or what kind of f-stop range should there be atleast for salt prints?

Here is photo of the negative on light table:

radiant · Jan 5, 2021

ProfessorC1983 said:
It's also worth mentioning that with staining developers (e.g. Pyrocat-HD) you get an effective boost in print contrast since the stain blocks more UV than visible light -- see Sandy King's article for more info and test data: https://sandykingphotography.com/resources/technical-writing/pyro-staining-developers

I find that Pyro-HD lets me develop negs around DR 1.5-1.8 that print more or less equally well on Grade 0/00 silver paper as well as alt processes like VDB and salt, assuming an appropriate scene brightness range. Whereas the less contrasty ones that end up around DR 0.9-1.2 are appropriate for either Grade 2/3 or classic cynanotype.

Pyro-HD sounds interesting. Lot of local shooters use it, maybe I should try it too!

How did you measure your DR?

koraks said:
Yes, that is exactly my experience. Feel free to rate your film about half a stop faster. In fact, I prefer to do this to keep peinting times manageable as otherwise the shadows get a bit dense (on the negative) to my liking.

Half stop sounds quite small amount, but I trust in you

koraks · Jan 5, 2021

vedostuu said:
Is there any way to approximate CI or what kind of f-stop range should there be atleast for salt prints?

Around 2.1-2.2 is fine; this is looking good!

radiant · Jan 5, 2021

koraks said:
Around 2.1-2.2 is fine; this is looking good!

So nice to hear! I unfortunately blew highlights quite bad (the flower). Well, that is what they call hands on practice

koraks · Jan 5, 2021

They might look blown out now, but wait until you've made the salt print. They may not be as far off the chart as you think they are!

osella · Jan 5, 2021

That negative looks pretty good to me. I don't make salt prints, but that negative would work pretty well for Pt/Pd too. The highlights are probably going to look blown for a negative meant for most alt processes.

RalphLambrecht · Jan 5, 2021

Lachlan Young said:
That's the theory - but in practice there can be quite wide variance between different products - compare Ilford's MG Cooltone FB and Warmtone FB - officially an exposure through a Grade 0 filter on cooltone equates to a DR of 1.15 and on warmtone to 1.6. Bit of a difference! Even at 00 on Cooltone, you're only getting 1.3. The other thing to watch out for is that the 00 curve behaviour in the shoulder on some papers (thus affecting shadows in the print) is less linear than at higher grades.

this seems like a reasonanble approach to me.

Lachlan Young · Jan 5, 2021

vedostuu said:
Pyro-HD sounds interesting. Lot of local shooters use it, maybe I should try it too!

The only possible advantage is that the stain may offer a little more density under UV illumination, making it hypothetically easier to use one neg for both silver gelatin and various alternative processes - but it's very open to question as to how effective that really is. You don't need any special developers to get the DR you need - PQ Universal will do it.

ProfessorC1983 · Jan 5, 2021

koraks said:
Salt requires a bit more contrast in my experience than VDB. For me, a good VdB negative prints well on grade 0, while a good salt negative doesn't quite print well on grade 00. Also VdB benefits from more shadow separation so I prefer to overexpose negatives for this process by up to a stop, while I underexposed them by half a stop for salt. VdB has a very pronounced s-curve while salt is much more linear. They're quite different animals in my experience.

Very true, and I should not have lumped them together as I'm only just beginning to experiment with salt! Still very much getting familiar with what type of negative is best suited to which alt process.

vedostuu said:
How did you measure your DR?

With a scanner and some digital magic, so probably not appropriate to go into detail in an analog forum...

Evaluating negative density range by contact printing on silver paper.

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