friday: Collected Maybe

Posted on Posted in alt photo, collotype, labnotes

many small readings. short hand notes.

st/ages of theory: how-to / what / why

learning from the hobby lobby means you may never know a reason. you probably won’t ask them questions, after-all, you and they are just hanging onto each other’s opinion. You will never ask where he saw that work. Unless you remember, because you were a member of the academy, you wouldn’t realize that geography was a strong barrier to exhibitions in the 70s and 80s.

Dichromated Gelatin

ask the other camps. look in books and journals. maybe google has a bigger, better memory than you realize.

The advantages of Dichromated Gelatin over Silver Halides are:

  • More efficient recording material.
  • Has less scattering.
  • Is more transparent.

as dichromate is exposed absorption spectra changes.

the broader the exposure spectrum, the deeper the hardening reaction.

characteristics are listed below.

  • Initial thickness of the gelatin layer
  • Initial hardness of the gelatin
  • Concentration of sensitizing dichromate bath
  • Drying conditions: temperature, humidity, and time
  • Exposure, wavelength and energy
  • Time delay between exposure and processing
  • Alkalinity and temperature of processing baths
  • Composition of processing baths
  • Time in processing baths
  • Recording geometry

Factors Influencing Light Geometry

(a) Size of the light source. The larger a source, the greater becomes the angle of light rays travelling from its edges and therefore the degree of undercutting.

(b) Position of the light source. The nearer a light source is to the vacuum frame the greater is its effective size. Conversely if the lamp is moved further away, so its effective size is reduced. It is good practice to increase lamp distance when exposing very fine detail work to reduce the effect of light undercutting if at all practical, (do not forget that the exposure time will have to be adjusted if an integrator is not fitted).

the “printing out” tanning is similar in contrast effect as the “developing out” of tanning developers. DAS / Dichromate systems share the exposure effect: judge by depth of “cure” — tanning, hardening of the colloid. DAS exposure should begin with 365nm wavelength.

Absorbance and sensitivity are different. This is partial explanation for why color of exposing light should be broader with a longer (more depth) exposure requirement.

delta Delta100

Posted on Posted in A Symbol Life, minimum daily requirement, the fora, the meta

three thoughts. one thing. A film and answers vs my own impulses.

How we get to something else has been a recurring part of my self-questions- those things we pick at between picking apart other things. Forums have strongly structured layouts, they are software impositions upon interaction. Questions seem to have a pattern of responses without regard to the forum goal or forum topic. All self supporting respondents seem to follow a similar pattern.

An instance (from 2017):

an experienced photographer asks: What developer / dilution gives the longest straight line curve on Ilford Delta 100? They have three developers available (TMAX RS, HC-110, D-76)

the response pattern: first response suggests a change in film. Follow-up is ask what the goal of the photographer is. Next, response to follow-ups. Finally, a proposed answer as they use the product.

Reading this 5 year old thread, I had an initial answer; it wasn’t any of the ones given. Why? Probably because I bring the topic a different reason for using the film: I use it as a separation negative component. Separation negatives don’t like compensating effects. No compression, please.

My answer would have been the TMAX RS. That developer isn’t available. The better developer for separations would be DK-50. If you don’t want to work from skratch then use an Ilford ready compound: Microphen.

He seems to have moved onto other matters. his website has a supporting techniques piece as well as a one month blog (2016)

“ that said, most of my contemporaries find this degree of technical application an extraneous exercise, but I find it essential in the process of making art. The accolades once betrothed to the silver saviors of modernism have long-since faded.” [chriswalkerphoto.com/vitae/supporting-techniques/ ]

These found topics hold interest because they may lead to work I would otherwise miss. It also gives me a chance to question my own response system. To monitor my own need to speak up. Save it. If it means enough: write it.

If it really means something: Do that something.