f/stop timer?

[Richard Rees]

Looking for the pro's and con's of using a f/stop timer, and what brand would you recommend or not recommend, thanks Richard

[Peter De Smidt]

I have and RH Design Stopclock professional. I love it. I don't know of any con's. I's my favorite piece of darkroom gear. http://www.rhdesigns.co.uk/darkroom/html/stopclock_professional.html

There's also: http://www.darkroomautomation.com/da-main.htm
Mr. Linden is a member here, and he's very helpful. I expect it's a great timer, but I haven't used one.

[kev curry]

Same here best thing Ive bought for the darkroom. The Stopclock pro is an awesome piece of kit. It makes f/stop and split grade printing easy and pleasurable. As far as companies go it dosent get any better for customer service than RH Designs.

[Peter De Smidt]

The main advantage of an F-stop timer is that time changes, and dodges and burns, become very intuitive. In addition test strips become evenly spaced.

[Brian C. Miller]

I bought the RH Designs Analyzer Pro. Really a handy device! :) The customer service is excellent, too.

[Jan Pedersen]

RH Designs Stop Clock Pro is really the next best invention since the cheese :)
I don't nearly use all the features but as said it is very intuitive to use it when you think in camera terms instead of seconds.

[jeroldharter]

I use RH Designs Stopclock Pro. Couldn't do without it at this point. It has two channels which makes split grade printing very easy. It has a test strip mode that allows you to expose each strip at a fraction of a stop more than the previous strip. It has additional channels that allow you to program in multiple burns such as edge burning or any other burn as f-stop increments to the primary exposure. It allows you to adjust the fractional f-stop increments for each step of exposure from 1/24 stop to 1 stop. I use 1/6 stop most of the time. It has a function to account for dry down. Once you test for drydown percentage (e.g. 7%) then you program that number in, generate your final, fine, wet print - then punch the drydown compensation button to expose the sheets of paper that will dry down to look like the wet print.

It is a huge time saver and it allows me to do complex exposure sequences that I never would have attempted with a regular timer, at least without a lot of swearing. There are many threads on this with more details. I think they make regular timers obsolete.

[Richard Rees]

Thanks for all the great info, after reading WAY BEYOND MONOCHROME the idea of a f/stop timer makes sense. Thanks again, Richard

[aduncanson]

I think that there are advantages to each. I own an RHDesigns timer, but sure wish it could display the exposure time directly in stops rather than in seconds. I do not find it intuitive that 13.454 seconds is 1/2 stop more than 9.514 seconds. I understand that the Darkroom Automation f-Stop Timer dispenses with seconds altogether and instead displays similar times as 3.7 and 3.2 stops (relative to 1 second) respectively. After a little practice, I found this handy and intuitive.

Darkroom Automation published a very hand pdf file (http://www.darkroomautomation.com/support/grastops.pdf) of a timer face marked in stops that can be printed, cut out and taped to the face of a common GraLab timer.

The RHDesigns timer has finer resolution, to 1/24th of a stop vs. Darkroom Automation's 0.1 stop, but I find that 1/6th of a stop change is sometimes hard to perceive in the print so this may not be an important advantage.

RHDesigns expressed amusement at my suggestion that they incorporate a mode displaying time in stops, and claimed that nobody had ever asked for that before.

Neither company picked up on my suggestion to use a spin knob to adjust the exposure time. Spinning the knob clockwise past 12 o'clock to the 6 o'clock position would add 1/2 stop, or counterclockwise to the 9 o'clock position would subtract 1/4 stop.

[jeroldharter]

aduncanson,

Interesting thoughts. I think it takes some time to get used to either system, RH Designs of Darkroom Automation. I have never used the DA timer but I suspect it takes time to get a feel for how many seconds are in "3.2" on the timer.

When I do dodges or burns I still like to count seconds in my head because I can't count in stops. On the RH timer, I might want to dodge a face in a photo by 1/3 stop, but I can easily figure out that that is, for example, 4.5 seconds by pushing the down button twice in the 1/6 stop mode which I usually use. So it is a simple matter of counting 4-5 seconds of dodge time during the main exposure. I am not sure how I would do that with a stops only display without extra steps.

I agree that the time measurements are not intuitive values for f-stop differences. However, it rarely matters. For example, whatever my base exposure time is, I might do a 2/6 stop edge burn. I just push the program button for the first edge burn and then the up button twice and repeat for each edge. I don't even have to look at the timer. But I like being able to see the seconds so I don't end up giving myself a 1 second dodge/burn that is impossible to do reliably.

I doubt the differences of 1/24 stop vs. 0.1 stop between the two make much difference.

[matthew klos]

this is crazy, i never even knew these things existed.

[Pavel+]

I'm about to buy a RH f/stop timer but am as of yet undecided between the analyzer pro or the StopClock pro. I do like the idea of dials, especially as described by aduncanson, and wish they would go to that as well as putting in a f/stop scale differential in a larger screen - but I would still like to have the actual time.

They seem to be a great company - something kind of rare.

[jeroldharter]

I think both RH and DA are great companies who design good products and who provide good support.

I have always been fascinated by analyzers thinking that I might measure my way to a good print. But for me, it just does not work that way and offers extra layers of complexity that bog down the process. I am going to do some test exposures no matter what the analyzer says and I know the neighborhood of a base exposure anyway. If I were a production printer and had to crank out many decent prints for a living, then an analyzer would be great. But for trying to make the finest print that I can, I have never found an analyzer to be very helpful (color work is different though). So I use the StopClock Pro for those reasons.

[nolindan]

Claimer: As most know, I am the owner of Darkroom Automation and the designer of the Darkroom Automation timer and meter. Comparisons of features of the RH and DA systems are based on my best knowledge, are certainly subject to correction, and are not intended to be in any way misleading.


I own an RHDesigns timer, but sure wish it could display the exposure time directly in stops rather than in seconds. I do not find it intuitive that 12.996 seconds is 1/2 stop more than 9.190 seconds. ...

Thanks, it is always nice to have a convert.

As you say, it is a lot easier to look at the display and see that 3.7 is half a stop more exposure than 3.2 stops. At least, I certainly find it so.

I have never understood why the RH timers display seconds.


RHDesigns expressed amusement at my suggestion that they incorporate a mode displaying time in stops, and claimed that nobody had ever asked for that before.

Queen Isabella to Columbus: “Sail West? How amusing. Nobody has asked for money to do that before.”

Enough of the cheeky stuff.


... I have never used the DA timer but I suspect it takes time to get a feel for how many seconds are in "3.2" on the timer.

It doesn’t really matter. Though for those of a binary bent the answer is that 3 stops is 2^3 seconds or 8 seconds and so 3.2 stops is at a guess around 9 to 10 seconds; 4 stops is 16 seconds, 5 is 32, etc. etc..

It’s not the time that matters but the exposure. Paper doesn’t care about time, per se, but about how much exposure it gets.

Think about it, what does it matter if the timer says 15 seconds? OK, so you know that you don’t have time for a cup of coffee, but apart from that issue you just set the timer to whatever it takes to expose the paper. Just what that number is has no other relevance - it’s just a number you set on the timer to get a good print. If you have an RH compensating timer for your cold-light head then setting the timer to 15 can result in a 10 second exposure with a ‘hot’ cold light or take 45 seconds with a frozen and shivering lamp. The 15 is just so many units of exposure (and just happens to correspond to the time in seconds for an average lamp temperature).

The Darkroom Automation system works completely in stops of exposure. The light intensity reading from the meter is in stops. Add the light intensity reading on the meter to the timer setting and one has the total exposure in stops. Any combination of meter reading and timer setting that adds to the same exposure produces the same tone on the paper. For the curious, a light intensity resulting in a reading of 10.0 on the meter produces max black on MGIV RC in 0.0 stops (1 second); a meter reading of 9.0 indicates it will take 1.0 stops (2 seconds), a reading of 8.0 will take 2.0 stops (4 seconds), and a reading of 0.1 says it will take 9.9 stops (955 seconds or 15+ minutes [reciprocity will of course come into play...] and you will have time for that cup of coffee after all).

The Darkroom Automation timer shows and counts down seconds when it makes an exposure - but the feature is more a ‘pacifier’, like the progress bar on a computer.


When I do dodges or burns I still like to count seconds in my head because I can't count in stops. On the RH timer, I might want to dodge a face in a photo by 1/3 stop, but I can easily figure out that that is, for example, 4.5 seconds by pushing the down button twice in the 1/6 stop mode which I usually use. So it is a simple matter of counting 4-5 seconds of dodge time during the main exposure. I am not sure how I would do that with a stops only display without extra steps.

The DA timer has a dodging feature. If you want to dodge by 1/3 of a stop you enter “d0.3”, insert the dodger and hit the expose button. Less keystrokes than counting out 1/6ths -- and the timer remembers what you did for when you make the next print. I believe the RH timer does somewhat the same thing but you have to do dodges as sort of inside-out burns. The DA timer breaks up multiple dodges so you can do a 2 stop dodge followed by a 3 stop dodge without any jiggery-pokery - something no other system will do.


I agree that the time measurements are not intuitive values for f-stop differences. However, it rarely matters.

Exactly - it’s just a number indicating exposure.

So it is a matter of which you find more convenient: stops or seconds.

To my mind if you are working in stops - it is an f-Stop timer after all - then a display in stops makes the most sense and is the more useful.


For example, whatever my base exposure time is, I might do a 2/6 stop edge burn. I just push the program button for the first edge burn and then the up button twice and repeat for each edge.

Or enter “b0.3” and press the footswitch or expose button - each exposures will burn 0.3 stops over the base exposure. No more keystrokes required - just move the burning card and tap the footswitch for each edge. Possibly the RH design is similar?

You can also use the timer's memory mode and save keystrokes print-to-print by programming a series of base exposure, dodge and burn sequences (and if you are so inclined a split grade filter change and a second set of base/dodge/burn exposures). Each press of the expose key/footswitch makes the exposure and advances to the next dodge or burn. I understand some RH timers have a similar feature.


But I like being able to see the seconds so I don't end up giving myself a 1 second dodge/burn that is impossible to do reliably.

Very good point.


I doubt the differences of 1/24 stop vs. 0.1 stop between the two make much difference.

0.1 stop of resolution means you are never more than 1/20th of a stop away from the optimum exposure. If the optimum sits between two 1/10ths then you are either 1/20th too light or 1/20th too dark. With 1/24ths you are never off more than 1/48th of a stop. Though if you have to add 2 stops by pressing the key once for each fraction of a stop it can be a drag - which is likely why most users seem to find 1/6ths convenient and adequate. An advantage to showing stops directly is one doesn’t have to count key presses and it allows the keys to ramp the exposure up and down.

* * *

The two systems take different approaches to solving the same problem. Though Richard likes to debate the point, the Darkroom Automation system is less automated(*), takes a bit more effort to use, offers more direct insight and control, and is the ‘stoppier’ of the two.

When used with the paper speed charts the Darkroom Automation system allows precise tone placement, with exposure and paper grade matched to the important points in the image. Many systems pick grade and exposure on the shadow and highlights with the result that the areas of interest get a lot of dodging and burning to get them in line. The opposite should be true - the areas of interest should match the paper and exposure and it is the shadows and highlights that should get the dodging and burning.

The Darkroom Automation system uses the actual HD curves for each paper. The response curve for a paper isn't any sort of ideal 'S' curve but is more like the mogul run on a ski course - full of dips and bumps. Only a system that uses the actual paper data for the whole curve can allow precise placement of midtones with concomitant determination of paper grade. If it is the highlights that are important the system can find the optimum paper grade for fitting the highlights, if the shadows the system can determine the best paper for the shadow contrast. A system that bases itself on two-point calibration only at one tone in the shadows and one tone in the highlights can not do an adequate job.

It is possible to use the DA system with its paper speed charts with any timer or meter. Of course, it works best with the equipment it was designed for.

As the saying goes: You pays your money and you takes your choice...

Darkroom Automation Web Page (http://www.darkroomautomation.com/da-main.htm)
--

* What can I say, the name was picked before the product concept was formed.

[Brian C. Miller]

Hi, Nick! Before I bought the RH Designs Analyzer Pro, I really gave serious thought to your product. No, really! ;)

The reason I went with RHD over DA is because of the built-in densiometer. Is it a highly precise tool? No, but it gets the job done very nicely. I had been printing using a Beseler enlarging meter and a Gralab 900. I made a little test strip maker out of some cardboard so I could expose the same strip image.

Now, I grab the meter, read a number of points from the negative, and then push a few buttons and print.

Here's a thought: why not make a model with a USB connection? Then it could be connected to a notebook or iPhone, and publish the API. That would be a great hit, as people would be writing software for your product. That would be leaps and bounds in front of everybody.

[evan clarke]

aduncanson,

Interesting thoughts. I think it takes some time to get used to either system, RH Designs of Darkroom Automation. I have never used the DA timer but I suspect it takes time to get a feel for how many seconds are in "3.2" on the timer.

When I do dodges or burns I still like to count seconds in my head because I can't count in stops. On the RH timer, I might want to dodge a face in a photo by 1/3 stop, but I can easily figure out that that is, for example, 4.5 seconds by pushing the down button twice in the 1/6 stop mode which I usually use. So it is a simple matter of counting 4-5 seconds of dodge time during the main exposure. I am not sure how I would do that with a stops only display without extra steps.

I agree that the time measurements are not intuitive values for f-stop differences. However, it rarely matters. For example, whatever my base exposure time is, I might do a 2/6 stop edge burn. I just push the program button for the first edge burn and then the up button twice and repeat for each edge. I don't even have to look at the timer. But I like being able to see the seconds so I don't end up giving myself a 1 second dodge/burn that is impossible to do reliably.

I doubt the differences of 1/24 stop vs. 0.1 stop between the two make much difference.

I have the Darkroom Automation timer and I got used to f-stop printing on the first print :) :)

[jeroldharter]

Nicholas,

Thanks for taking the time to clarify all of those points. Very helpful.

In regard to my comments about dodging in seconds. That is a holdover of my pre-f-stop printing days. A lot of times when I do my test strips I can see that I want to dodge the face by 2/6 of a stop. After I judge my base exposure, I figure out how many seconds I need to dodge and don't really use timer functions for that.

I did not realize that your timer displays seconds in addition to stops. I think that is a great feature to have both.

[Marek Warunkiewicz]

...RHDesigns expressed amusement at my suggestion that they incorporate a mode displaying time in stops, and claimed that nobody had ever asked for that before...


Funny, I asked them that as well a few months ago... I own one but would like to have it in stops as well and not time.

[jeroldharter]

I have the Darkroom Automation timer and I got used to f-stop printing on the first print :) :)

Evan,

I am disappointed. I figured you would have both the DA and RH timers.

[evan clarke]

Evan,

I am disappointed. I figured you would have both the DA and RH timers.

HaHa, it's on the agenda. I could actually use 3 or 4 more f stop timers, I am continuously moving mine around:D ..Evan

[Erik Larsen]

Yeah, I think having seconds showing as it counts down is a good feature because you can see at a glance how long you have to bob and weave with a dodge stick or burn tool. Nicholas, if you took paypal on your site I would buy a timer and footswtitch tonight:)
Erik

[nolindan]

if you took paypal ...

Try http://www.digitaltruth.com/store/cart/Timers-Meters-p-1-c-102.html

[Shen45]

Or if you made a 220 - 240 volt AC version. Both timers look great by the way.

[Peter De Smidt]

My stopclock professional goes down to at least 1/12th of a stop. For regular grade papers, that's a little bit overkill, but for doing a print at grade 5 it's valuable.

I'm a little suspicious of programmed paper curves or charts of dichroic values, as enlargers vary quite a bit, since filters fade, light boxes yellow... The best thing I ever did to improve my printing was to follow Paul Butzi's method for getting constant highlight density with a specific paper over all of the various contrast grades the paper is capable of. The second best was getting an f-stop timer.

[Brian C. Miller]

The Analyzer Pro and Zone master have a calibration mode, where you can store the properties of up to eight papers. There is a step wedge included, and a calibrated strip. The meter is programmed with both an offset and absolute value derived from the test strips created from the process. (Video link, QuickTime (http://www.rhdesigns.co.uk/darkroom/html/demo_videos.html))

[gbogatko]

The DA timer breaks up multiple dodges so you can do a 2 stop dodge followed by a 3 stop dodge without any jiggery-pokery - something no other system will do.


The instructions for doing multiple dodges says

"To dodge, insert all the dodger(s) and press the expose key. Then remove the
dodger for the completed dodge - leaving the others in place - and press the
expose key for the next dodge.

When I read that, I imagined an octopus holding 2-4 dodging wands each of which was moving in a different pattern at the same time. Could you explain a little more about what you are talking about?

Thanks,

George

[Peter De Smidt]

Don't forget to get a foot switch whichever you go with.

[nolindan]

"To dodge, insert all the dodger(s) and press the expose key" ... Could you explain a little more about what you are talking about?

The situation arises when you have multiple dodges that add up to more than the exposure time.

As an example, if you have a 1 stop dodge and a 2 stop dodge then it is very hard to do them in a serial fashion: you would insert the first dodger for first 1/2 of the exposure and the second dodger for the remaining 3/4 - which is a bit of a problem as there isn't a 3/4 of an exposure left.

Instead you need to insert both dodgers for 1/2 the exposure time and then leave the 2 stop dodger in for 1/4 of the time and then expose with no dodgers for 1/4 of the time. There is no other way to do it. The need to be an octopus is the downside of multiple dodging.

The timer does the partitioning for you: You set the timer to the shortest dodge time put the dodgers in and expose; set the timer to the next dodge time put the remaining dodger(s) in and expose; and repeat as desired.

If there is only one dodge then you insert the dodger, make the dodged exposure and then make the finishing exposure and you are done.

These techniques are shown graphically in the quick guide:
http://www.darkroomautomation.com/support/mfsquicks.pdf

If you have only two short dodges then they can be done serially. To avoid being an octopus you can set the first dodge as a base exposure and the second dodge as a burn exposure.

As Peter recommends, a footswitch makes things a lot easier - with any timer.

[gbogatko]

Thanks!
And I have the gear on order already!!

George

[coops]

The timer i got from DA is the best peice of equipment I ever bought fro my little darkroom. And the footswitch is great also.You will love it.

[David Aimone]

I have to agree. I just purchased one, and in the two darkroom printing sessions I've done it's transformed my printing process.


The timer i got from DA is the best peice of equipment I ever bought fro my little darkroom. And the footswitch is great also.You will love it.

[David Aimone]

Nicholas,

Is there any way to convert f-stops or 1/10 of an f-stop (on your timer) to percentage for drydown? I'm finding that I'm darkening somewhere between about .1 to .2 f-stops between wet and dry.

David

[nolindan]

The timer has dry-down compensation as a percentage.

1/10th of a stop is about 7%. So try 10% as a first go, not a very original number, I'm afraid. You can often get to the same end by decreasing the wattage of the inspection light.

[David Aimone]

Just came from a printing session. LOVE this timer...

[ac12]

I'm trying to understand how you make a multi segment test strip w an F-stop timer. Each segment will have a significantly different time of exposure to be 1 stop apart, i.e.,
2-4-8-16-32 seconds

[David Aimone]

I'm still fairly new to the process, but if I understand your question correctly:

With the f-stop timer, you can adjust the exposure by as small as 1/10 of an f-stop, but yes, the time intervals won't be the same. They will increase for each subsequent test strip segment.

So with the darkroom automation timer, you would select a base time to begin at in f-stop intervals, say 2.0. Then you can select the interval for each segment, say 0.2.
So your first exposure is the 2.0, the second is 2.2, the third, 2.4, etc. If you start with a base of 2.5 for example, with a segment interval of 0.5, your first exposure is 2.5, the second is 3.0, the third is 3.5 and so on.

The base number can be varied based on the aperture that the lens is set to. For example, 2.0 at f/16 is the same as 3.0 at f/22, so it's easy to change the timer base or the lens aperture. If you're at 2.0 and f/16, but you want to stop down to f/22, just change your base to 3.0. All the subsequent time intervals change automatically. In this case they would get longer.

So, the timer does count down seconds and fractions thereof when running, but everything is based on f-stops. On a test strip, each segment will be a fraction of a f-stop, so times will vary. In fact, as I said, they will increase for each segment as each additional exposure will take longer to apply the equivalent f-stop interval.

I hope this helps a "bit".


I'm trying to understand how you make a multi segment test strip w an F-stop timer. Each segment will have a significantly different time of exposure to be 1 stop apart, i.e.,
2-4-8-16-32 seconds