fstop printing has been used since digital timers entered the darkroom. In 1985 Gene Nocon introduced a timer designed specifically for the f-stop timing method of printing.
In making prints setting a starting point on the timer (and lens aperture) is first estimated. Using prior experience, yours or others, will get you going. All the emulsion makers provided booklets, guides, even calculators that could get you a good start point.
The “step test” is a basic skill shared by all printers. Making this test strip provides visual estimate of print density (exposure) on a single piece of paper. The timing sequence can be in increments of the same amount or in varying amounts. Linear scale printing can make judging intermediate amounts more difficult than fstop method. When dodging / burning, this is harder with a linear scale.
5
+5 =10
+5 =15
+5 =20
+5 =25
4
8
16
32
linear or fstop scale
With split filter printing using fstop timer with 1/4 stop gradation provides most of the control used in exposing BW prints.
Nocon patent June 1985 for timer element. He made use of British government grant money to make the first ones.
He also had a design patent for the key layout. Simple calculator style system with fractional stops .
His patent spends much of its text describing the calculation method.
[https://www.asmp.org/articles/gene-nocon-passes.html ] 404 link
Mr. Nocon, whose photograph of Prince Andrew and Sarah Ferguson was used as the royal wedding commemorative stamp in Great Britain, died after suffering a heart attack Nov. 20 ,2011 at his home in San Diego. He was 65. born on Dec. 26, 1945. lived in London from 1973 to 1990 and earned the Ilford Printer of the Year award in 1980
what does the fresh stuff look like? does the color of the powder make a difference in the resulting developer?
Just another post fight on the bragboards, but it also reminds you, check the internet. Whatever the posters with more posts than pictures say— verify it. don’t get trumpd again.
glycin color [TCI] White to Gray to Brown powder to crystal. Notice that color correlates with size of — crystal is darker. Preparation see: Meldola, Foster, Brightman, J. Chem. Soc. 111, 552 (1917) It’s prepared from p-aminophenol and chloracetic acid. [ basis note: Chemical Storage InfoLIGHT SENSITIVE, AIR SENSITIVE: Keep tightly closed in light-resistant containers]
So, Amidol in the US comes from Artcraft or Formulary. December 2022
https://artcraftchemicals.com lists Amidol — chinese. Interestingly, this is the store that as of today is being boasted about as supplying the good English brand, not the evil chinese brand. Can’t say much about the company’s description. No SDS. They also say this: “Chinese Amidol, much better pricing than other Amidol sellers who are selling the Chinese stuff at a premium.”
Glycis / N-(4-Hydroxyphenyl)glycine / CAS 122-87-2 [over 97% purity] color is white – grayish yellow red
Using the CAS numbers will get you to different datasheets. color is seen in purity. the less pure the material the more color the chemical takes on. In purist assay Amidol and Glycin are mostly clear. This last only hours after the kettle.
Each of these absorb water; amidol darkens with exposure to light. Amidol works long past its darkest changes. Tray life is shortened, very little print stain occurs. Not the case with glycin which picks up moisture going darker and tending toward ‘dye’ form which will stain photographic paper.
These are items to keep in cold, dry, dark store. Freezers are the likely place. Date your purchase. Use the glycin within 2 years. Amidol keeps for decades. The Chinese stuff can, should be filtered. It was purchased as dye precursor so was intended to be purified further. It wasn’t contaminated by bad metal kettles nor storage drums.
Personally, having seen Formulary storage, I’m surprised anything works. Although Bryant Lab wasn’t much better back in “the day.”
notes from 2004 ” The stain is most evident when the amidol print is compared to the MQ print on the same paper. The Bryant amidol is the lightest I have among several samples. Based on my previous experience with amidols from various sources, I do not believe that a better result would be obtained with any other sample yielding a colored solution. On the contrary, I think most if not all solutions, acid or otherwise, whose color is owed to amidol are likely to stain the fiber print, and I would venture that the darker the working solution happens to be, the more pronounced the stain will be, regardless of what formula is used.
AND
“British Journal of Photography” on March 13, 1914 (p 198) in which the writer, one “T. Trevelyn,” claims that both potassium and chrome alum added to the developing solution will prevent amidol stain.
the staining seems more related to Ilford papers than to the Amidol. [2004]
from original meanings: photo lab chemistry from the middle of last century.
these terms have been modified in this century.
from my wall.amidol spoonful method. add KBr
or 2-3 ml of your 1% BZT solution per liter of developer — image tone.
recall: amidol is called a “depth” developer.
for glycin alternate developer consider Foma’s PW warmtone
Reminder: most amidol formulations are effective, working the same, so pick any and apply. Amidol is the easy way to make developer. Water ,Sodium sulfite, and amidol…
The lesson: ask bigger google searches until you find bigger sites. I found the apenas site looking at Youtube. Rather than spending time on the devoted but declining photrio/largeformat 20th century enthusiasts of all things, check this century; then, read a book. Search using google books, and the internet archive. Much will become clear. Last century is well preserved.
To make the bleach first part you can use: only Part A is needed.
Working on: LED again. 9th street. the StarBergs. Steichen’s only picture.
A book to consider:
Book Building: Dayanita Singh
Dayanita Singh is a book artist who stretches the imagination of what a book can be, transcending the spaces between publishing and art. Book Building traces the journeys of Singh’s books, from the first, Zakir Hussain (1986), to her latest, Zakir Hussain Maquette (2019), showing the spectrum of her book-building process, from idea to material object and how she inventively circulates them in the art world and beyond.
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