Negatives for silver chloride / Adox Lupex / AZO / Lodima - which AI has it right

[pkr1979]

Hi all,

So, Im having some fun asking AI for advice. The feedback from various services doesn't always correspond. I always assumed negatives for Adox Lupex (grade 3) were best if they were low contrast, and Claude agrees with me. However, both ChatGPT and Grok claim more contrast is needed to match the paper.

Who is right?

Cheers
Peter

 

[ezphotolessons]

Hi-Peter
SIlver Chloride papers require higher contrast, like making a "salted-paper-print"
It-seems ChatGPT and Grok were on-the-money
Here is a website link that might-anser additional-questions

Michael A. Smith and Paula Chamlee

 

[pkr1979]

Its a shame that forum is unavailable - probably lots of good info there.

 

[koraks]

SIlver Chloride papers require higher contrast, like making a "salted-paper-print"

No! Current production Adox Lupex is a very high-contrast develop-out paper (as opposed to POP salted paper); it's ca. grade 4. It requires thin negatives.
Lodima and its Kodak predecessors were made in various grades AFAIK but I think mostly 2 and 3.

Keep in mind too that the density range that's optimal for a salted paper print exceeds that of any regular grade; for salt prints, a density range of 2.1logD or even longer works best. That's grade 0/00 territory - and beyond.

 

[ezphotolessons]

apologies I should've just-said "silver-chloride-paper needs higher contrast than regular-photo-paper"

 

[koraks]

apologies I should've just-said "silver-chloride-paper needs higher contrast than regular-photo-paper"

Although that would also be doubtful, or as in the case of present-day Adox Lupex actually wrong given the ca. grade 4 contrast of that paper. So it requires thinner negatives than for most other papers, although most papers of course are VC.

 

[Lachlan Young]

Current production Adox Lupex is a very high-contrast develop-out paper (as opposed to POP salted paper); it's ca. grade 4. It requires thin negatives.
Lodima and its Kodak predecessors were made in various grades AFAIK but I think mostly 2 and 3.

The bigger issue is that people see a grade number and neither interrogate the exposure scale or characteristic curve - chloride papers were the first to really be able to achieve a genuine grade 5/ ES of 0.5 (decades of research effort went into making enlarging speed papers capable of the same exposure scale) and a visually favourable curve shape across the grades, but the distribution of some of the lower grades could wander quite considerably from what we might describe e.g. a 'normal' G2 instead being closer to a G1/ ES 1.35.

 

[pkr1979]

The bigger issue is that people see a grade number and neither interrogate the exposure scale or characteristic curve - chloride papers were the first to really be able to achieve a genuine grade 5/ ES of 0.5 (decades of research effort went into making enlarging speed papers capable of the same exposure scale) and a visually favourable curve shape across the grades, but the distribution of some of the lower grades could wander quite considerably from what we might describe e.g. a 'normal' G2 instead being closer to a G1/ ES 1.35.

What does this mean when making negatives intended for Adox Lupex at grade 3? That I actually want a higher than 'regular' CI despite the grade number?

 

[Lachlan Young]

What does this mean when making negatives intended for Adox Lupex at grade 3? That I actually want a higher than 'regular' CI despite the grade number?

Not necessarily - just do a step wedge test and it'll tell you what sort of neg you'll need, relative to your own process parameters.

 

[pkr1979]

I'm not sure I have ever done that... made a step wedge test I mean. ChatGPT and Grok knew it was a contrasty paper, but because of what you mention they argued the negative needed to be contrasty to.

 

[retina_restoration]

Hi-Peter
SIlver Chloride papers require higher contrast, like making a "salted-paper-print"

Absolutely incorrect. AZO type papers are typically too contrasty for normal negatives, as they are in the Grade 3 to Grade 4 contrast range. That means you need a FLAT negative — much less contrasty than normal.

 

[ezphotolessons]

Although that would also be doubtful, or as in the case of present-day Adox Lupex actually wrong given the ca. grade 4 contrast of that paper. So it requires thinner negatives than for most other papers, although most papers of course are VC.

apologies. I was working off my-own-4decadesexperience printing-on-1940s,1990s and 2000s AZO-Grade III. negatives with contrast-and--density that-would-yield-a 20 second exposure, like "1930s-drug-store-negatives" I sometimes re-print. I unfortunately have printed on-silver-chloride and-VC with thin-negatives, I do-not-wish-that-on-anyone. I have no experience with current ADOX or Lodima-Production-Papers. I thought everyone-used contrast-and-dense-film for silver chloride paper, maybe it is just everyone-my-teacher-taught?

It's a shame that forum is unavailable - probably lots of good info there.

I hope the-rest-of the AZO-information was-helpful at-least. I-make-a dense-negative-with-contrast, I seem to-be-a-minority.