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 |
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
F-stop Printing
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