Category: coursenotes

from lectures and presentations I’ve taught

Time travel

Posted on Posted in coursenotes, film, Theory

imagine you can travel back to the 1940s. You will be an early producer of matrix emulsions. You cannot take equipment with you, although you may take your curent knowledge, as well as  being able to lookup  patents issued before 2000.

Most importantly: you know it is possible, even limited to the engineering,  mechanical, and chemical systems of the 40s, 50s. Always an advantage second movers have — certainty.

If I say “film” how far does that word take you — where? if you are an Internet generation film might only take you to Kodak and Hollywood.. your search might also only take you to saran wrap.

however if you know of more than one film maker and you don’t run that word on or hyphenated you may know of Ilford, Dupont, Ansco,  Agfa, Defender or more. If those names are in your dictionary then you’ll understand the time travel exercise and you’ll understand the notion of film being discussed.

How does the emulsion become — what is included in the kettle, how is it mixed, how does it become a coating on the base, why doesn’t it fall off upon drying… many more questions will sprout — but they were all answered robustly even by 1940. 

Every bit of knowledge needed to make a matrix film was common trade knowledge by 1941 — panchromatic films remained closely guarded insights until 1950. 

There were enough solutions to the problems that engineering and industrial chemists were selecting choices for cost-market reasons.

why don’t you gather a group of three travelers around a studio table to plot your journey — I won’t be going. Safe travels.

Continue reading “Time travel” →

photolab: Ds

Posted on Posted in book shelf, coursenotes, exs notebook, film, labnotes

Old books offer first knowledge.What is the difference between Kodak D11 and Ilford ID-11… don’t let names/numbers trip you. Learning means acquiring references… first sources, old texts are fundamental.
the language of those authors may not be your current language .. the language of this age.. phrasing changes. Learn to play. It isn’t hard.

The D’s offer an arc of contrast .. you must know the concept of paper grade as expressed in corresponding texts and references by the manufacturer. In this case Kodak. Kodak, Agfa, Ilford are quite specific about what a grade is. Just because you don’t know, perhaps you don’t understand, perhaps you haven’t researched it, doesn’t mean it doesn’t exist.. manufacturers and their customers were/are different. That number two is not a universal amongst all 15 1950s manufacturers. The survivors have maintained their definitions and AIM points.

What was once known remains known. What you learned then, you can use now. Even with deeper definition of ISO.


their common ground was logarithms… Density ranges are a 2-point AIM method. Not up to full answer to the requests made of professional dye transfer labs.

AI fails: using Claude Sonnet (apr 2026) I requested pH cacluations for a developer, a stop bath, and a fixer. It failed to calculate any of them correctly. After being told the correct answer to the developer calculation the response was:

Estimated pH: 11.5 – 12.0

Most likely ≈ 11.8

Reconciling the pH Discrepancy

You’re absolutely right — for a color reversal first developer, the target pH of 10.1–10.3 makes perfect sense. This is a more controlled, restrained alkalinity compared to a high-energy B&W developer.

Where My Estimate Went Wrong

I likely over-weighted the NaOH and Na₂CO₃ as if they act independently at full strength. In reality:

Buffering interactions reduce the effective pH:

Lesson Noted

For developer formulations with high sulfite (≥40 g/L), the sulfite buffer must be treated as the primary pH anchor, not a passive preservative. My initial approach overestimated the free alkalinity. Thank you for the correction — this is a valuable calibration point.

Context Check ✓

This formulation is consistent with a high-energy universal or film developer (similar in character to D-76 boosted with extra carbonate and NaOH, or a tropical/push developer). Typical working pH for carbonate-NaOH developers is 11.5–12.2 — this estimate fits perfectly.

⚠️ At pH ~11.8, handle with care — use gloves and eye protection. The NaOH and carbonate make this solution caustic enough to cause skin/eye irritation.

Notice, Cl Sonnet continues to treat the pH as higher than now calculated. It mixes high-activity, low-activity without consistency.

Summary (RL) — the agents remain lacking in “intelligence” — they calculate — but not as well as task designed calculators. They remain low cost party tricksters… that are obscuring the basics of photolabs. In this, they join the bulletin board outcrops of the hobby pool. Beware!

Discourses on Art

Posted on Posted in art school, coursenotes, meaning, studio table, Theory

Book by age, or by contents. How do you choose the text for your table? Mine is filled and emptied by whim; by wandering among the stacks. Like a sleepwalker without slippers. Old books are kept not maintained. They become overlaid with marks upon readings. Reynolds is an old text without many current readers. I never spend more than a frew minutes with it, although it draws me in enough times over the years to remain on in the main stacks.

Joshua Reynolds. [1723- 1792]

Further:

Additional ballast from the “other”:

  • The ONLY ABSOLUTE TRUTH is that there are NO ABSOLUTE TRUTHS (Feyerabend) 
  • I define postmodern as incredulity toward metanarratives … (Jean-François Lyotard)
  • Finally, if nothing can be truly asserted, even the following claim would be false, the claim that there is no true assertion. (Aristotle)
  • If anyone thinks nothing is to be known, he does not even know whether that can be known, as he says he knows nothing. (Lucretius)
  • And isn’t it a bad thing to be deceived about the truth, and a good thing to know what the truth is? For I assume that by knowing the truth you mean knowing things as they really are. (Plato)