View Poll Results: Would you buy a timer/shutter tester?
- 20. You may not vote on this poll
No way, a stopwatch is all I need
Yes, I must have one at any price
Yes, if under $200
Yes, if under $100
Yes, if under $50
Yes, if under $25
Yes, if under $10
I'd have to think that variations in bulb output and color temperature, filter aging, and paper lot to lot variation will matter much more than variations in a timer that is either crystal controlled (any microprocessor controlled timer) or line frequency controlled (gralab 300-type).
A light meter (Ilford EM-10, or one of the high end timers with a light sensing) will allow a basic compensation for those changing parameters. When I do use anything but test strips, I use an EM-10 to get close on the first print, but there is still plenty of testing and tweaking to get a print that I am happy with the second time. I am sure the combined meter/timers are more convenient, but the EM-10 works and is cheap.
10% was mearly being used as an easy example
Originally Posted by panastasia
That being said, picking up an item used, you do not know what you are going to get, how it was treated, etc.
I agree with Jon King on this one. If you come back to a negative a few years after printing it these days, the paper will be different, your developer might be different, and you will be different, and you might interpret the negative differently, even if you thought you wanted it to be the same at first. This is part of the reason I'm skeptical about "editions" of photographs, particularly if the entire edition isn't printed at one time.
Fred Picker used to tell us that when you make a print none of the variables will EVER be the same....as mentioned in previous posts plus the fact of the time of year;water; temp;and whatever else is going on...to actually assume that you can go back to the original conditions is ridiculous....on the other hand when I go back and redo prints they usually end up to be better than the original...go figure!!
The thoughts that come to me...
I like the concept - perhaps not for all the reasons you have come up with. I'm not sure an accurate and precise darkroom timer will control enough variables to save me much future work.
Let's see... developer strength, solution temperature, paper formulations change over time and papers get discontinued, voltages vary, new bulb in enlarger, slightly different enlarger height, hard to set aperture to exactly same opening, close yes, exact ummm, agitation of paper in developer, how much unintended flashing happens when safelight that's maginally safe just barely exposes enough to bring image a bit closer to threshold, age of enlarging paper, any marginal exposure to sulfide fumes etc ... There are a lot of variables.
Nonetheless, I'd take a look at a timer such as you describe - if the control set doesn't require a post doc.
I have taken a quick look at a couple of other timers - not as much of a look as they deserve mind you - but I was left with the impression I would end up using only the top 5% of the functions because the rest would fade from my memory from just a bit too much complexity.
I'm no luddite. I do some VB database design for fun. But I like my tool controls intuitive. My own limited experience coding / designing leads me to believe it is a very different experience to use a device one has designed one's self, than trying to use someone else's design.
Regardless, the thinks I'd look for:
I'd like a timer that reads accurate and precise in chunks of .1 sec to 99 sec.
I'd like a solid shutter tester.
I'd like a timer that allows me to easily control two channels for blue and green lighting for variable contrast papers.
It would be a huge plus to have four channels to also allow controlled flashing on VC paper.
Audible cues for burning and dodging?
Thanks for reading this,
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Not that is interesting.
Originally Posted by CBG
I guess I did not think of the angle, "Why test the time, why not build a better timer"
What you suggest it quite doable.
If for not other reason than I do not have a new house to build a darkroom, I will play with that idea instead.
Here are my thouhgts, based on what you posted:
2 - 4 digit readout banks
push buttons for setting time (cycle through 0 - 9)
One outlet each: Blue, green, safe light, flasher
burn/dodge beep (timescale?)
Anything else? Not asking for the kitchen sink, though. Control layout would be simple and intuitive.
Not to say it would be easy, but we are not talking terrible difficult, either. Even with what little I remember of electronics, I should be able to put together something workable.
> I'm not sure an accurate and precise darkroom timer will control enough variables to save me much future work.
It's not what it controls but how it lets you control it.
> developer strength, solution temperature, paper formulation, agitation ...
It is possible to get identical prints over long spans of time. The hard variable to control is the gradual shift in paper contrast over time.
Precise metering and voltage regulation are key. You can do without a regulator if you print late at night or in the middle of the afternoon when voltage is stable.
Naturally, fresh developer, reasonably constant temperature and timed development are also required.
> I'd look at a timer ... if the control set doesn't require a post doc
I don't know of any post-docs in Darkroom Automation's customer base. A few retired MD's. A _lot_ of retiring professionals printing a final portfolio who are in need of something to make the job go faster (and better and cheaper) -- they tend to be a flinty no-BS crowd.
> I was left with the impression I would end up using only the top 5% of the functions
Same with everybody. Problem is everyone has a different 5%. And that 5% changes with time. For function overload I think DVD players take the cake but everyone seems to be able to get what they want out of their DVD player.
> It would be a huge plus to have four channels to also allow controlled flashing on VC paper.
Now there is a first -- a unique 5%. Should the channels track as two sets of two or as one set of four? If it as two sets of two channels with optional tracking within each set then I have just the timer for you.
On the subject of timer errors:
- The timers most prone to error are the psuedo-digital ones with a pair of 0-9 knobs. The biggest errors are when switching decades, as in 19 seconds to 20 seconds. They also suffer from noise in the switch contacts and can be erratic - Radio Shack contact cleaner usually fixes the eraticity.
- GraLabs and their kin are prone to two errors: You can't set them to much better than 1/3 second; Each exposure is off by a fixed time amount because of the switch/clockwork mechanism. As a result five 2-second exposures rarely equal one 10-second exposure, and test strips are often iffy.
- Many digital timers use an RC time-base and may have a 1% constant fast/slow error. This will have no real effect on exposure as the error is repeatable and 1% is about 1/70th of a stop.
The information that came with my old GraLab 400 series (analog type) timers advises against using voltage regulated current - they wont work properly.
Originally Posted by Nicholas Lindan
"Pictures are not incidental frills to a text; they are essences of our distinctive way of knowing." Stephen J. Gould
Analog timers have synchronous AC motors in them and these may have trouble with the two most common forms of regulation:
Originally Posted by panastasia
- Ferroresonant transformers put out a square wave that may give some motors problems. 'Harmonized'/CVS ferros put out a sine wave that should work OK with any timer.
- Solid-state regulators put out a chopped AC or DC waveform that, again, will give many synchronous motors the fits.
You can use both of these regulators if you put them between the timer and the enlarger.
The motors in drills and most appliances are 'universal' motors that don't care what sort of power they see. Fans use induction motors that, like synchronous motors, want to see well behaved AC.