I made a simplified version of the table in the Way Beyond Monchrome book, see attached pdf. It uses 1/4 stop increments and the times are rounded to the nearest whole second for times more then 10s. That makes it easier to select it on a regular timer and I find that it's accurate enough. I've used this table for a number of years now and it works for me. Test strip increments are listed as well. So if you want to do a test strip from 20s to 40s in 1/4 stop steps, the time sequence will be: 20s, +4s, +4s, +6s, +6s.
I use the Rudman chart too. His chart goes under 5 seconds (Ralph's doesn't) Often I find myself with crazy short exposure times when printing old 35mm negs.There is a chart for this in Tim Rudmans book on printing
We have been using this method for over 30 years. At first using a basic timer and just doing the=math in ones head
The school can’t afford to purchase f-Stop timers but we still use+the method=using newer timers
I also printed out a stoffers 21 step wedge image along with a huge chart from Tim and after explaining how this works my students find it easy to do
I'm quite dyslexic when it comes to math (seriously) Whilst I understand the first part of your post perfectly I was wondering if you could explain the last two lines please."2", "1.4", "1.26" and a calculator. (those are the time multiplication factors for full, half and third stop).
So if your base time is 41 seconds, you know 82, 57.4, and 51.6 are the new times for a full, half and third stop increment.
So, when using contrast grades 0 to 1.5, use "2" or "1.4"
When using contrast grades 2.5 and higher, use "1.26"
"2", "1.4", "1.26" and a calculator. (those are the time multiplication factors for full, half and third stop).
So if your base time is 41 seconds, you know 82, 57.4, and 51.6 are the new times for a full, half and third stop increment.
So, when using contrast grades 0 to 1.5, use "2" or "1.4"
When using contrast grades 2.5 and higher, use "1.26"
I'm quite dyslexic when it comes to math (seriously) Whilst I understand the first part of your post perfectly I was wondering if you could explain the last two lines please.
<5s is not printing time;it's a flash exposure;mine starts at 16s, which I think is the min printing time to allow for some dodging;any less and dodging starts getting tricky.I use the Rudman chart too. His chart goes under 5 seconds (Ralph's doesn't) Often I find myself with crazy short exposure times when printing old 35mm negs.
"2", "1.4", "1.26" and a calculator. (those are the time multiplication factors for full, half and third stop)...
"2", "1.4", "1.26" and a calculator. (those are the time multiplication factors for full, half and third stop).
So if your base time is 41 seconds, you know 82, 57.4, and 51.6 are the new times for a full, half and third stop increment.
So, when using contrast grades 0 to 1.5, use "2" or "1.4"
When using contrast grades 2.5 and higher, use "1.26"
A one-third stop change of exposure for a print on 00 paper is not detectable by my eye.I'm quite dyslexic when it comes to math (seriously) Whilst I understand the first part of your post perfectly I was wondering if you could explain the last two lines please.
I still think you guys are wasting time with f-stops instead of thinking in percentages.
Thanks for the clear explanation. For this next piece of information which may be useful I need to thank Ralph Lambrecht. He spotted this very problem and devised a test strip printer that allows the user to easily expose the same strip each time. It's a great piece of kit. It gives 7 exposures of the same part of the print projection on a 5x7 piece of paper.The problem with the conventional 'test strip' is that each strip is on a different part of the image. This did not make sense to me in 1973 when, I was shown how to do it, and still does not fit my workflow.
believe it or not but, I can definately see the difference of a 1/12 stop in highlights and midtones and f-stoptiming is just as easy as percentages;yet to me,easier to record and remember. A good f-stop timer is an invaluable tool in the darkroom for every dicerning printer.So let's see... a full stop change is 100% more exposure, a half-stop is 40% more and a third-stop is roughly 25% more. I can figure all that without a calculator or a fancy timer.
So, using your example, a base time of 41 seconds plus 100% gets me 82 seconds. Plus 40 percent (4.1 x 4) gets me 57.4 and plus 25% (4.1 + 4.1 + 2.05) gets me 51.25 (really close to the third-stop increment; only 0.35 seconds difference. I defy anyone to tell the difference between prints made at 51.6 and 51.25 seconds...). And I can do all this in my head in a fraction of a second. And, I can easily use intermediate values, e.g. 35%.
I still think you guys are wasting time with f-stops instead of thinking in percentages.
Best,
Doremus
me too and Yes; to each his own;to a photographer, f/stops feel more natural than percentages;f/stops are a key variable for photographic exposures; in the field,exposing negatives,working with filters,belloes extensions;why not in the darkroom too?Ralph,
To each his own. I imagine working with an f-stop timer greatly reduces the amount of mental gymnastics one has to do. I print with a metronome, so percentages work best for me. The result is the same: proportional exposure control. It just seems like a lot of people here like to do a lot of calculating with square roots while in the darkroom. I prefer to make prints.
Best,
Doremus
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