Tag: film

Answers Hidden

Posted on Posted in da net, meaning, the foraTagged , , , ,

Those who do not show their work have a reason.

Consider the circumstance: you know that ISO 100 film is more sensitive than Ilford Multigrade paper. You may even know by what factors. How you learned to gauge the exposure for paper also applies to film. If your darkroom prints are exposed for 8 to 20 seconds, what would you guess the exposure would be for an ISO 100 film? Certainly not the same time. Film is much more sensitive than paper. You could determine a relationship between the film and the paper used in your darkroom.

The standard light has been a mark of lab experience for more than 70 years.

Direct questions deserve direct answers.

Direct answer: The exposure is 5 seconds at 3 footcandle at the film plane.

Answers which involve much handwaving are smoke screens… cover ups.

As one form of claiming power, of having influence among the Hobby Snobby Forums, you gain points by being obtuse in your answers. The more complicated the answer, the less likely you will have to demonstrate the answer. Hobbyists are filling idle time. They don’t need the answer; if they did, they could test their system, learning the answer specific to their methods and tools.

What would be useful is teaching them how to setup, configure and use their specifics. That can be done using Web2 features. Not interested. The last group I taught has grown onto their own studios… Ask them how.

Key point: learn how to question the answers given. This will free you to find your answers to your questions.

friday: Collected Maybe

Posted on Posted in alt photo, collotype, labnotesTagged , ,

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.

Open Registration

Posted on Posted in coursenotes, dye transfer, labnotes, overnight notes, The PostTagged , ,

Much of darkroom work is hand waving. Aligning images to build a print is part of the world of assembly processes.

Projecting a beam of light through a modulator, such as a piece of film, is the way of the darkroom. The enlarger is light and lens. We increase our control by being able to change the color and intensity of the light. These are the little pieces we build a world with.

Many Added

Here, we see a color print, made from separate BW negatives, using filters, manual registration, and RA-4 color paper.

tricolor type C printing

Notice how casual the assembly is. No film punch; no micro calipered, glass carriers; none of the carping crap posted on the Film Forum by slow moving Flim Flammers.

Many Divided

Next, Jerry Uelsman shows his method of making combination prints. He uses several enlargers, each with a negative of one element of the finished image.

Uelsmann in darkroom

There are people who use the computer to write their essays and there are people who still use a yellow pad and a pencil. They both can write excellent essays, stories or whatever. The process is the means by which you complete the image, but you don’t want it to be the end. There was a point at which the emphasis was on the Zone System that was all so technical. So you had this precise full tonal scale image, but what was the subject matter? It’s a cat or a sunset. So what? I’m committed to the darkroom, but I believe that if I had been 20 years younger when Photoshop came out with its visual options, I might be sitting in front of a computer rather than standing in front of an enlarger.

Jerry Uelsmann