Yeah, I'm really wondering if there is a better way to actually implement dodge in one of these timers.
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I just use the Stop Clock metronome to time my burns and dodges. The display changes depending upon what function you choose. For example, it will display the steps the increase/decrease buttons employ in fractions of stops, but you need to confirm that and remember what you have set, because the display pretty much only shows seconds while in use as a timer. It has an indicator that shows whether it's set to spit-grade mode, and which filter the time is set for. And some other things I don't use. You can download the user manual for a previous version that is pretty close to the current one at https://rhdesigns.co.uk/wp-content/uploads/2020/04/StopClock_v3.pdfIf it were simple, it would probably have been implemented a long time agoBurn is definitely easier, but even then I don't like to give up dodge, sometimes 2x dodge replaces 5x burn.
I'm curious what route you take with your timer.
May I ask, do you own a timer from RH design? Can you confirm/refute what I wrote a bit above? What does the sequence/program look like there (StopClock Pro)? Is it rows of numbers (seconds), or is there some information about the stops?
That's certainly another work-able approach, and maybe one that can be expanded on Perhaps a little utility function to tell the user how long each dodge lasts, and then they either just count it out or get extra audio/visual cues during the base exposure.I just use the Stop Clock metronome to time my burns and dodges.
Not sure about your question. I determine the amount of dodging and burning necessary. I just use the metronome to time them.That's certainly another work-able approach, and maybe one that can be expanded on Perhaps a little utility function to tell the user how long each dodge lasts, and then they either just count it out or get extra audio/visual cues during the base exposure.
(The only problem with audio cues during the base exposure is its hard to provide a "warning countdown", and again the issue of overlapping dodge periods. And the problem with visual cues is that you might not be looking at the timer during exposure. But its somewhere to start brainstorming from.)
Disclaimer: I am the owner, dog walker and head bottle washer at Darkroom Automation and the designer of its products.
Choosing Twixt Tweedle Dee and Tweedle Dum:
The decision between the two commercial alternatives - Darkroom Automation and RH Designs - may be made on a few criteria:
- If you already have the DA meter and like it, then the DA timer would be the better choice as the DA timer integrates very well with your existing DA meter.
- If you live in Europe then the RH Designs timer may be your best alternative as it is made for 220V operation out of the box. The DA timer can be ordered wired for 220V for a small fee, but it's not the most convenient thing as the plugs are all wrong for your country (I would have thought von der Leyen would have decreed the use of a 'Euro Plug' by now).
- If you are of an analytical bent the DA system may appeal to you. The DA system is a pure stops timer - everything is in stops, though the timer displays remaining seconds during the exposure as a pacifier. The DA system is more accurate and gives you precisely the tones you desire (assuming, of course, you know what those tones are).
- If you are of a touchy-feely bent then RH timer may appeal as it pretty much a seconds timer that adjusts in stops and thus less of a paradigm shift. Some photographers think the RH's 1/12th of a stop is a better unit than the 1/10 of a stop adjustment of the DA timer. You will get no argument from me that base 12 is far superior to base 10 - but I have used base 10 all my life and think best in that base. Any civilization that got past counting on its fingers and put a bit of thought into the matter settled on base 12/60/360.
- If you like a 'one box does it all' approach then RH may be the best choice - but you have to like the way the box does it.
- DA's two box solution splits exposure determination from exposure control. As the word "Automation" in the name suggests, the Darkroom Automation system has very little automation in it.
- If you do a lot of dodging then you may prefer the DA timer - more on that below. The RH Designs timer does dodges as 'inside out' burns.
- And, finally, the decision may boil down to your taste in timers: There is no accounting for taste; Chacun à son goût; Gustibus non est disputandum and all that.
On Dodging
Yeah, multiple dodges with the current Darkroom Automation timer can be a bit of a PITA - although in this respect the DA timer is still better than any other timer on the market (or, at least TTBOMK, which doesn't have a whole lot of K sometimes - why dodging is missing from other timers is a mystery to me).
The DA timer's "octopus dodging" requires that all multiple dodgers are in the light path at the beginning of the dodge sequence and get removed as the dodging sequence progresses. The timer is designed this way so you can dodge a print to your heart's content and never run out of time. There is no other solution to this (possible) problem.
As an example:
The problem: A 1.0 stop dodge followed by a 1.2 stop dodge can't be done in the conventional manner. The 1.0 stop dodge takes 50% of the exposure time and the 1.2 stop dodge takes 60% - so the combination takes 110% of the total exposure - bit of a bummer, that.
The solution: With octopus dodging the first dodge exposure is for 1.0 stop (50%) with both dodgers in the light path; the second exposure is for dodging the remaining 0.2 stops (10%); the final exposure then exposes for the remaining 40% of the time (all times approx.). I have a few prints that require this sort of dodging - aided by contraptions made from cardboard, coat hangers and sticky-tape - standard DIY dodging fare.
A Dodging Update
There is a software update in the works for the DA timer that will allow 'normal' dodging in addition to the present 'octopus' dodging. Older timers can be updated for a nominal $10 charge + shipping. There will also be a DIY version so not so much shipping is needed.
On Test Strips
Of all the features of f-Stop timers I consider test strip generation to be the least relevant. An auto-reset clockwork Time-O-Lite and a foot switch make short work of linear test strips. f-Stop and linear test strips that hover near to the final exposure are indistinguishable. One made at 16 seconds in 1 second intervals will look exactly the same as one made at 4.0 stops in 0.1 stop intervals.
That said, I find the unlimited test strip feature of the DA timer to be really useful for determining the sensitivity and HD curve of a paper. In doing this I may make test strips going from 0.0 stops (1 second) to 5.0 stops (32 seconds) in 0.1 stop intervals - that's five 10" length test strips with a total of 50 test patches.
* * *
On wishful thinking - I like to think that if Ansel Adams were to be alive today he would be using an f-Stop timer. Edward Weston, not so much.
On "investing" in the higher priced alternative rather than merely "purchasing" the lower priced product - I have always held that in investing the rule is "buy low." To this end, counting elephants is your best investment in a timer; put the money you save in your 401K or the S&P 500.
On the high price of both f-Stop timers - all I can say is that if f-Stop timers sold in the 1,000's they would be priced at $29.95 each.
There is a software update in the works for the DA timer that will allow 'normal' dodging in addition to the present 'octopus' dodging. Older timers can be updated for a nominal $10 charge + shipping. There will also be a DIY version so not so much shipping is needed.
Here's how I did one of my last dodges using the DA F-stop timer ... A 4 stop ... base exposure is 16 seconds. When I first set the ... dodge to 4.0 stops, I was expecting the timer to give me the equivalent amount of time to carry out my dodges. However, it stopped short (about 14.?? to 15.?? seconds) and gave me the finish prompt i.e. 'FIN" to expose the remainder of the base exposure.
I was surprised that the timer allowed it, but to recover that bit of remaining time for dodging, I was able to set a dodge time longer than the 'H' channel 4 stop base exposure.
... do you have an estimate when the software update might be available?
Dodging can get a bit, er, strange sometimes. But the timer did things correctly.
I have always admonished myself to never, ever pre-announce a release.
Its a lot easier to make a timer do super-short exposures than an actual enlarger, though. At least with an enlarger that uses an incandescent light source, it takes a certain amount of time for the bulb to turn on and turn off. This can be measured, and in my own case is approximately 300-500ms (I think, I haven't checked in a while). So there is a minimum exposure time in practice.What follows is a mathematical diversion and is not relevant to using an f-Stop timer. You never see any of this when using a timer. Skip it all if you aren't into all the geeky stuff.
You can dodge for 99 stops if you like. The math, that the timer does for you, is 4 stops - 99 stops = -95 stops, or 2^-95 = 2.52 * 10^-29 seconds for the finishing exposure.
The timer will do very short exposures, though not that short. Quettahertz microprocessors being thin on the ground.
Its a lot easier to make a timer do super-short exposures than an actual enlarger, though. At least with an enlarger that uses an incandescent light source, it takes a certain amount of time for the bulb to turn on and turn off. This can be measured, and in my own case is approximately 300-500ms (I think, I haven't checked in a while). So there is a minimum exposure time in practice.
It seems to me that while the filament is heating or cooling, its spectrum will be shifted toward red, emitting proportionally less blue, reducing contrast. So I would expect an incremental test strip to have lower contrast than a strip with a complete exposure on each patch. Have you seen this effect with short incremental exposures?
Mark
Darkroom Automation has an application note for determining lamp delay time: http://www.darkroomautomation.com/support/AppNotePH212LampDelay.pdf The method can be used with any timer to determine the effect in your setup. Compensating for lamp delay is possible in the Darkroom Automation timer, I don't know about the Dektronics design - I believe these are the only two timers in the running.
For a standard PH212 bulb the effective warm-up time is ~50mSec. This is pretty trivial in the grand scheme of things.
On my LPL 7452L, the "effective warm-up" was measured at 317ms and the "effective cool-down" was measured at 55ms, giving a total "lamp delay" of 372ms. (some minor difference from last time, either due to different equipment or environmental conditions) Of course the actual warm-up/cool-down time was longer than that.
I have the LPL 7452 but what is the "L" designation that you refer to?
Comparing the specs of the two models on KHB, it seems like the main difference is the column height. Otherwise the specs look identical.
The LPL Enlarger Guide: LPL model 7452 4x5 Enlargers
a guide to the LPL 7452 (Saunders/LPL 4550XL) 4x5 enlarger and accessorieswww.khbphotografix.com
These don't seem to come around that often. I'd say it's worth whatever price the buyer and seller agree upon. Likely in the several-hundred-dollars range, but I don't know how to define "several".What is a 120v RHDesigns Analyzer Pro in excellent++ (almost like new) condition - complete with cables, footswitch, and probe worth these days?
Mike
On the desk lamp, the "effective warm-up" was measured at 45ms and the "effective cool-down" was measured at 5ms, giving a total "lamp delay" of 50ms, exactly matching the numbers mentioned above. Again, the actual warm-up/cool-down time was a bit longer, as expected.
Though I have the DA timer, this thread has me interested in learning more about setting the lamp delay for my LPL's quartz-halogen lamp using the application note provided above by Mr. Linden.
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