I'm hoping to hear from folks who have printed using both methods. I'm choosing a new timer - some can do both with reduced features, some only one or the other. How has working in stops helped your printing? I'm considering a RH LE stop clock (does both). I guess I could do it with a Kearsage, but that seems like a bit of a hassle, with charts, etc. Am I wrong? Thanks Very Much, not planning on buying another for a long time - This will really cut into my film/paper $, but the Gralab 300 amd the guessing on burn times seems less than ideal. Thanks in Advance to EVERYONE - It's been terrific to read and learn.

-- Wayne Brown (wayneb@involved.com), September 02, 2000

Answers

Working in stops with a seconds time is not hard. Just remember to double or halve the time for one stop. If your base exposure is 12 seconds, 1 stop less is 6 seconds, 1 stop more is 24 seconds. 1/2 stop less is 3 seconds, 1/2 stop more is 6 seconds.

-- Terry Carraway (TCarraway@compuserve.com), September 02, 2000.

Wayne, the name of the game is to produce nice prints, using a combination of both time AND f-stops. Generally speaking, you should use the middle of your f-stop range on your lens (usually about three stops down from maximum), and try to keep your exposures within a reasonable range, say about five to ten seconds, whenever possible.

There will be times when this is impossible. A large print from a dense negative will require lots of exposure, and you probably will find that your times climb into minutes, if you try to use that centre range on your lens! Likewise, a small, wallet-sized print from a large negative will call for very short times; you will have to deal with each situation (and each negative) as you encounter them. Neutral density filters, a lower wattage enlarger bulb, or a glass negative carrier for long exposures may be required.

Not to be too much of a nit-picker, but photographic exposures are calculated geometrically, not arithmetically. They advance, in half-stops, by a progression of 2^0.5, which is approximately 1.414.

A half-stop more than six seconds is 6 x 1.414 = 8.484, which rounds off to 8.5 seconds, not nine seconds. A half-stop more than 8.5 seconds is 8.5 x 1.414 = 12.019, which rounds off to twelve seconds, one stop more than six seconds.

By using an aritmetic method, a half-stop more than six seconds is nine seconds (6 x 1.5 = 9); a half stop more than nine seconds is 13.5 seconds (9 x 1.5 = 13.5), which is NOT a full stop more than six seconds. That's an error of 12.5%, enough to consign a print to the waste basket!

-- Terrence Brennan (tbrennan13@hotmail.com), September 02, 2000.

I'm not a regular to this list [ or even a regular lurker ;-) ]but saw your question looking through my 'favourites' list on a slow day - don't get too many of those sadly.

I am a convert from linear timing to f-stop timers and naturally therefore recommend the jump enthusiastically! Gene Nocon, who designed the concept and the first f-stop timer, frequently urged me to try one. Being slow to change for the sake of change I agreed to let him demonstrate it a couple of times but couldn't see any reason why it would be right for me. (this must be over 20 yrs ago so its not that new now). I liked working the way I always had. When requipping a new d'room about 13 yrs ago I decided to get one and make myself use it, - I can't imagine now why I didn't do it right away! I would feel lost without it and automatically think 'stops' when looking at a print and calculating changes required. I think this comes naturally to most photographers. The good things are - apart from visualising density changes in f- fractions which seems more normal than thinking in seconds - the timers are programmable for sequences, easily chageable, no missed steps in complex prints, and above all when you change from any print size to any other size - or a series of sizes - the only thing you change is the initial exposure (many easy ways of working that out) and this is a tremendous boon. All the d & B steps are exactly the same and are already in the timer. Go for it, you won't regret it. Richard Ross's stop clock series of timers are more complex than gene Nocons but they are also more sophisticated and more flexible. They can also be used as linear timers so you really have nothing to lose, and if you don't like it further down the line you can always sell it. They can do other things too, even couple up to an analyser. They are extremely reliable and come with good support and tons of info in written form and on the web. No I don't work for him! (But I do know him and vouch for his honesty) They are good products and I plan to get one shortly as my Nocon timer is now failing. Re your point on guessing burn in times - there is no future in that. You may think buying a good timer eats into your 'paper $' - but so does repeatedly getting the prints wrong. You need a reliable repeatable finely adjustable tool. Sooner or later you may get into split grading or fine D&B on hard grades and you will need fine controls using 1/10ths of a stop or less. There is only one tool that I know of that gives all these facilities. Tim Rudman

-- tim rudman (tim.rudman@virgin.net), September 02, 2000.

The expert speaks! It is nice to get input from THE Dr Tim Rudman.

For more information on the f-stop printing methodology, please refer to www.rhdesigns.co.uk. It is a wonderfully logical system and I regret that it has taken me so long to find out about Dr Ross'es StopClock Timer.

-- Erik X (xx@xx.com), September 02, 2000.

You are right, I should have put the website in - it was a long day! Apart from www.rhdesigns.co.uk you may want to look at www.users.znet.co.uk.ktphotonics. Chris woodhouse works with Richard Ross on the products. Richard has a Phd in electronics as well as being a photographer - so you can see the background to these products - Chris does the software side and is also deeply into curves and sensitometry, so the 'marriage'is good for the products and the users. You will find data on support and use of the system via these pages. It's really nice to see someone putting up this sort of support and data rather than just putting products out to a designer and letting the user get on with it. Tim Rudman. (P.S. by all means mention my name if you want to if you contact them - but I promise you that I'm not on commission!)

-- tim rudman (tim.rudman@virgin.net), September 03, 2000.

BTW three stops down from maximum is NOT necessarily the sharpest point. In fact with most enlarging lenses anything more than f5.6 is starting to get into loss of sharpness due to diffraction. Anything less than 1-2 stops down from maximum also looses sharpness.

Read Ctein's "Post Exposure" for some serious enlarging lens testing.

-- Terry Carraway (TCarraway@compuserve.com), September 03, 2000.

All these guys know far more about this than I, but when I converted from my (much loved) Gralab 300 to a digital, it was night and day. Put the 300 to work for film processing where it belongs and make the jump. At the very least you'll never have to ask yourself "what was the exposure for that test strip I just did?"

-- Conrad Hoffman (choffman@rpa.net), September 03, 2000.

Having learned the decimal system for counting, I find it easier to think in terms of percent changes than in fractions of stops. However, once you learn either system, there is probably no difference.

-- Chris Ellinger (ellinger@umich.edu), September 05, 2000.

I have an article on making test exposures in 1/4-stop intervals at http://unblinkingeye.com/Articles/TestExpo/testexpo.html. I use a regular Graylab digital timer, having never heard of one that automatically calculates in stops (I'd like to know more!). Typically, if your exposures are 20 seconds or below you can make your test strip in 3-second increments with few problems, but much above 20 seconds you will do better to use accurate 1/4-stop increments.

-- Ed Buffaloe (edbuffaloe@unblinkingeye.com), September 05, 2000.

Far be it from me to correct the very great Tim Rudman but the correct URL is

http://www.users.zetnet.co.uk/ktphotonics/

We are not worthy, we are not worthy... :-)

-- Mani Sitaraman (bindumani@pacific.net.sg), September 11, 2000.

Who's Tim Rudman? Some point and shoot jockey? James

-- james (james_mickelson@hotmail.com), September 11, 2000.

Just found this site and was browsing around. for what is worth, i have been teaching my students to use the fstop approach for years. then found out a year or so ago that someone was making a timer that work with fstops. I came upon my method by accident when it became clear that beginners had a very hard time decideding on burning in time and usually gave up before getting even close. I teach them to relate the hightlights to middle grade (zone v) and then decided which shade of light gray to white they want the area. I don't use Zone system termnogoly(as to scare off folks) but teach them to make decision based on those zones. It helps them make a better starting stab. As others have mentioned use the 300 for film and paper, not printing. We are using beseler repeating timers, some old some new. understanding the concept in my opinon is the important thing, not the timer. however, i have not used the fstop time and might change my mind . if you have any other questions please don't hesitate to email me.

-- Ann CLancy (aclancy@mediaone.con), October 13, 2000.

Dr Tim Rudman is NOT some point and shoot LUMBERJACK, that is for sure.

-- Erik X (xx@xx.com), October 13, 2000.

Terrence Brennan seems to claim that a print exposed for 9 seconds instead of 8.5 seconds would be thrown out because it's not precisely 1/2 stop more than 6 seconds? Are we making prints or tuning pianos?

I set enlarging time in approximate f-stops with a conventional timer but stick with whole second steps. Yes, I am of the 1/2 stop is 50% more ROT school, but I don't carry it past one step. I don't blindly follow the rule to conclude that 6 doubled is 13.5 or I work in 1/2, 1/4 and ocassionally 1/8 stop increments. To move up or down approx. 1/2 stop in whole seconds I need to start with at least a 12 second base exposure. When I'm moving in full or 1/2 stop steps I'm at the test strip stage (test square for me actually). For 1/4 stop I move in 20% steps, 1/8 stop in 10% steps.

-- Tim Brown (brownt@ase.com), October 14, 2000.

I got one! I got one! Lumberjack. PS- Tell Tim that Gene says Hi.

-- james (james_mickelson@hotmail.com), October 14, 2000.