Category: overnight notes

Notes on…

Posted on Posted in overnight notes

Keyed color processes

Avoiding distractions

Dithering and the ink/pigment print. Pounding one contrast into another.

karoshi”, or “death from overwork”

Three Letters… Separated by amateur hours:

did he gain clarity, typing skill, or something else.

26-May-2012, 03:50

 If needed, add more BTZ, in 25ml / liter amounts. However, you can only do this twice or three times more before you kill your developer.

in a thread: Benzotriazole (BZT) use in defogging bromide papers

years later, 2023:

in thread: Benzotriazole Questions

BenzoTriAzole is the way the components should be divided up, hence, BTA is the proper acronym. BTZ is seen often, but is erroneous.

Note: the used acronym, in photoland is BZT, or BZTA, not BTZ. The enthusiastic expert (above) is typing, or thinking, out of sync. Chemists often use BZT as shorthand. The less used form, although the one preferred by emulsion chemists is: BTAZ 

As in: 

Do not use denatured alcohol, as the denaturant can be harmful to photographic processes.

Do use alcohol, iso propyl alcohol or other water miscible organic solvents. I usually use 1% in DW though.

For a 2% solution of BTAZ in alcohol use 2 g BTAZ in 98 g alcohol. This makes 2% wt/wt BTAZ in solvent.

This is true for any mixture regardless of density. That is why weight is better than density.
Be cautious in handling benzotriazole, especially in powdered form. It is extremely toxic so avoid inhaling the powder particles. I recommend you download the MSDS before using.
---
The effects of benzotriazole and bromide are more. detectable at low densities. This is obvious with the observed values for base plus fog. As development time increases or  when agitation is employed the effect of bromide becomes insignificant compared to that of benzotriazole as the density continues to build up with time, the effect of the benzotriazole level ceases to be a significant factor in the resulting contrast and speed values. 

benzotriazole has an effect on the developed density levels with Increasing development time. This is more evident at the lower exposure levels. 

common acronyms to facilitate discussion.

TAI: 4-hydroxy-6-methyl-1,3,3a,7-tetrazaindene
PMT: 1-phenyl-5-mercaptotetrazole
2-MBI: 2-mercaptobenzimidazole
6-NBI: 6-nitrobenzimidazole
MBTA: 5-methylbenzotriazole
Sodium carbonate (anhy)10 g
Benzotriazole10 g
Water to 1 litre
Ilford IBT

[sidebar on use in film is in my PanF for masking post ]

Dmax of BW paper.

is determined by the paper. The shape of the curve is altered by development. Kodak D-72 (Dektol) can be used as a reference developer when discussing curve shape. Reproduction image used by the eye is based upon toe and shoulder shape. Sharp shoulder and high Dmax is less often chosen that a softer shoulder with lower Dmax. Open shadow seems darker even with the same Dmax. Usual Dmax of glossy paper is 2 -> 2.3; with matte paper is 1.8-> 2.0. Specialty papers (lithography) have Dmax of 3.2

Goniophotometry: the measure of density as a function of angle of light and viewing system

John Chiara: Process

Posted on Posted in A Symbol Life, on photographers, overnight notes, Prints, Theory: landscape

American. b. 1971, in San Francisco, California

 It’s rare for a photographer to push the technical edge of the medium. And rarer still to reanimate corners of the world seen and forgotten by hundreds of thousands of eyes every day. — Ian Bourland

After dedicating an extended period in 1995 to making contact prints from his 2-1/4″ x 2-1/4 inch negatives, John Chiara decided that too much information was lost in the darkroom enlargement process. Over the next six years he developed his own equipment and processes to make first-generation unique photographs without using film. 

Chiara developed a process that is part photography, part sculpture, and part event. It is an undertaking requiring invention in his tools and patience in using them. [from his bio]

Process isn’t the same as procedure. Mr. Chiara has extended his process to such an extent that it has become a featured point in discussions around his imaging.

Large. Tonal inversion. Color inversion. Put paper in the wrong place. Expose paper to the wrong light-type. Use the much seen, the much ignored. Take as much time as needed. These are the procedures that he uses.

It is easy to overlook these works. Easier for those of us who can readily understand the means and methods, the mode of this process. We shouldn’t. We should take his work on his terms, trying to get to where he has gotten — not in recognition of his work, but so we can use it to open our own work… or, for some, renew our efforts.

Find your process within your procedure.