Enlarger timer which does fractions of a second

rrusso · Nov 17, 2017

spijker said:
Care to clarify with a numerical example?

Sure - just to clarify and give proper credit, these figures were taken from the chart in the book Way Beyond Monochrome, co-authored by our very own Ralph Lambrecht...

Let's assume a base exposure time of 12s. If you have an area of the image which needs -2/3 of a stop, you will subtract 4.4s, so that area will receive 7.6s total. Another area needs +2/3 of a stop...but you will add 7s, giving that area a total of 19s. Notice the difference in the times in burning vs dodging - minus and plus 2/3 aren't the same number.

But here's the thing...I used a nice round number for the base time, but that might not always be the case. If you're making your test strips in f stop increments (which are easier to interpret), the base time could be 14.3, 22.6, 10.7...whatever. And then your dodging and burning times are all over the place.

Now...I'm not saying your method of rounding the numbers up or down is wrong or bad, but if you're doing it the "proper" way (if there is such a thing), then the tenths are important.

Vaughn · Nov 17, 2017

Measurebaters...

darkroommike · Nov 17, 2017

Vaughn said:
Measurebaters...

Oh that's good.

And for all those chasing perfection:

Accuracy to 1/100th of a second on an enlarger timer?
Do you also compensate for the time the lamp requires to come to full brightness,
voltage variations,
temperature of your developer,
the ratio of light to dark tones in your print,
the reduction potential of your print developer, which changes with every print?

Blessed Ansel used a metronome to time his exposures and processing in the darkroom.

Sirius Glass · Nov 17, 2017

I stop the lens down enough that I do not have to deal with fractional seconds, only integer seconds.

spijker · Nov 18, 2017

Measurebaters ... that's exactly my point. I got the impression from the earlier posts in this thread that people are putting too much importance on the 0.1 s accuracy and I tried to explain with an example that it's usually not that important.

Inspired by the f-stop table on page 508 in Way Beyond Monochrome 2nd edition, I wrote a similar chart in Excel for myself but with a 1/4 stop step size instead of 1/6 stop. Because my experience with the RH-design Analyser Pro (photo club darkroom) was that 1/4 stop increments is small enough for me. I did some error analysis and came to the conclusion that as long as I stay above 10 s (incl dodging) I don't need to bother fractional seconds. I'm no longer a member of the photo club and have a darkroom at home with a simple IC Enlarger Timer that was part of the package that I bought. I'm still planning to build an Arduino f-stop timer but that hasn't happened yet. So I use this paper chart instead and it means that I only use times that are listed on this chart. My exposure times are not all over the place times but always on a grid of 1/4 stop starting at 10 s. So far that has worked well for me. The advantage is that you can use this with a simple timer but also with a metronome and it is accurate enough. Also the math is simple, the numbers are easy to remember and it's less knob turning when I do a test strip. All that contributes to me having a more pleasant experience in the darkroom without sacrificing print quality.

I've attached my f-stop chart for those of you that want to give this a try. The test strip rows show the time increments for 1/4 stop or 1/2 stop.

RalphLambrecht · Nov 18, 2017

rrusso said:
Sure - just to clarify and give proper credit, these figures were taken from the chart in the book Way Beyond Monochrome, co-authored by our very own Ralph Lambrecht...

Let's assume a base exposure time of 12s. If you have an area of the image which needs -2/3 of a stop, you will subtract 4.4s, so that area will receive 7.6s total. Another area needs +2/3 of a stop...but you will add 7s, giving that area a total of 19s. Notice the difference in the times in burning vs dodging - minus and plus 2/3 aren't the same number.

But here's the thing...I used a nice round number for the base time, but that might not always be the case. If you're making your test strips in f stop increments (which are easier to interpret), the base time could be 14.3, 22.6, 10.7...whatever. And then your dodging and burning times are all over the place.

Now...I'm not saying your method of rounding the numbers up or down is wrong or bad, but if you're doing it the "proper" way (if there is such a thing), then the tenths are important.

rounding up or down to the next full second will not stop you from becoming the next photographic super talent.

RalphLambrecht · Nov 18, 2017

darkroommike said:
Oh that's good.

And for all those chasing perfection:

Accuracy to 1/100th of a second on an enlarger timer?

Do you also compensate for the time the lamp requires to come to full brightness,

voltage variations,

temperature of your developer,

the ratio of light to dark tones in your print,

the reduction potential of your print developer, which changes with every print?

Blessed Ansel used a metronome to time his exposures and processing in the darkroom.

Actually my RHDesigns timer really does. It's a function of the f/stop timer to wait for lamp and voltage stabilizer ramp up. With my Durst L1200, it made a visible difference especially in the test strips where the delay adds up otherwise.

RalphLambrecht · Nov 18, 2017

adelorenzo said:
The one I use is an Omega digital timer that will do 0.1 second increments to a maximum of 99.9 seconds. It has a knob for each digit so very quick and easy to adjust. Also a footswitch too which I really like.

I also have a basic Saunders IC timer that will do the same although no digital display. Something like this.

I'm sure if you post a want to buy ad here on the forum you'll get something that works in your price range.

I didn't like the foot switch on mine; always stepped on it inadvertently in the dark.

MattKing · Nov 18, 2017

spijker said:
I got the impression from the earlier posts in this thread that people are putting too much importance on the 0.1 s accuracy and I tried to explain with an example that it's usually not that important.

I'm not going to disagree with you about something that works for you.
There are a number of factors that together make it advantageous for me to have a timer that at least offers 0.1 second increments:
- I see a significant difference between 1/6 and 1/3 of a stop exposure change;
- I make extensive use of the f/stop exposure table in "Way Beyond Monochrome";
- I reasonably frequently find myself in a situation where in order to lengthen the exposure time for some or all components of a print exposure past 10 seconds I would have to stop my enlarging lens down to its minimum aperture, which I prefer to avoid;
- I perceive a lot of benefit from being able to work within a consistent framework, and wish to avoid an approach where rounding a time off to the nearest second may have more of an effect on one part of a print's exposure than on another part of a print's exposure; and
- I particularly want to avoid a situation where round off variations end up being cumulative.

For many prints, I can happily get by without the 0.1 second increments. For some of my prints, the option is useful. For some reason, those prints that might benefit from it are often the most complex ones.

By the way, I agree that lamp warm-up and cool-down times are important, but I think having the option of 0.1 second increments makes it easier to take them into account.

Doremus Scudder · Nov 18, 2017

Just to clarify: I'm not saying that 1/10-second intervals are not important sometimes, just that "after a certain point" they aren't. That point is the time at which 1/10-second makes absolutely no practical difference in the final print. Sure, when exposing faster color papers at shorter than 10-second exposures, you might need tenths of a second. But then, you could just use the smaller scale on the timer that allows tenths, couldn't you? (I believe that was the kind of time Doc described in his original post: one with a short-time scale that went from 0-9.9 seconds and allowed increments of 1/10-second, and a longer scale with 1-99 seconds.) My point is: after you get past 10 seconds or so, 1/10-second accuracy makes very little difference in the final print and after 20 seconds or so, nothing whatsoever noticeable.

As for f-stop timing: I find it elegant and intelligent and completely too cumbersome for me to use in the darkroom. I accomplish exactly the same thing without fancy timers or tables or figuring exposures in tenths of a second by simply using percentages. I make test strips in (rounded) 20% intervals. I adjust my exposure by percentages of my base exposure and I figure out my dodging and burning schemes in percentages of my base exposure. It's just as easy to learn to anticipate a 20% or a 15% or a 50% difference in exposure as it is to think in 1/3, 2/3 or 1/4 stop. And, I don't have to do anything but move a decimal point and do simple multiplication in my head. If f-stop timing floats your boat, fine, but I'm doing exactly the same thing with a metronome and basic arithmetic; even more elegant and intelligent IM-HO.

If you find yourself wrestling with fraction-of-a-second exposures, maybe you just need to relax and lengthen your exposure time a bit

Best,

Doremus

Hilo · Nov 18, 2017

To the original poster: indeed you have not gone mad, the Kearsarge 301 does the 1/10th seconds only up to 10 seconds. After that only 1 second steps. Has worked fine for me for about 30 years!

ic-racer · Nov 18, 2017

Did you get a timer yet? I wonder which one you got. I see all the new ones at Freestyle don't satisfy your criteria. I also see all the ones in my darkroom (3 total) can do 99.9, but they are all dedicated units directly connected to the enlarger power supply.

Vaughn · Nov 18, 2017

I am sorry for the measurebater comment -- in the end it is about getting the print one wants in the way one thinks best.

When I was silver printing, I aimed for an exposure time of around 20 seconds. This would give me a slightly light print, then I burned in spurts of that exposure time for the few minutes (up to 15 minutes) to bring the print up to the image I wanted (usually no dodging). I saw it as using chisels of light to dive deeper into the paper, spending 10 to 12 hours exposing 10 sheets of paper to get (hopefully) 3 copies of one image.

Probably was a strange way of working, but it kept me at an intersection of art and science where I felt the magic happened. I am at a different intersection of the same paths now -- straight printing in alt processes, but still with the magic in mind.

An older 16x20 silver print from 4x5. Truman Cove, West Coast of the South Island, NZ

Sirius Glass · Nov 18, 2017

Vaughn said:
I am sorry for the measurebater comment

I am not. I was amused. The point is that a tenth of a second accuracy is rarely needed.

Vaughn · Nov 18, 2017

All siriusness aside, if worrying about 1/10th seconds get in the way of making the image one wants, then it is a danger...but if doing so helps one create the image one wants, then it is a blessing.

Kawaiithulhu · Nov 18, 2017

ND filter works wonders if times are too short: I'm just sayin' that there are many ways to think outside the diffusion box beyond cranking down the f-stops.

When I used to have a very amateur darkroom my exposures typically ran 10-20 seconds, lots of time to even out variables I couldn't control like tenths of seconds or lamp startup times. The whole point is to make variables you cannot control, like those mentioned, a small portion of the overall sequence and short exposures exaggerate that portion.

Now I'm wondering if there can be a reasonable DIY timed relay with light probe that can measure the total actual exposure including lamp startup and dimming to aging to give 100% repeatable results despite un-filtered power and different lamp temperatures, etc... Time would be a matter of light and not seconds.

RalphLambrecht · Nov 19, 2017

MattKing said:
I'm not going to disagree with you about something that works for you.
There are a number of factors that together make it advantageous for me to have a timer that at least offers 0.1 second increments:
- I see a significant difference between 1/6 and 1/3 of a stop exposure change.

Oh, definitely; It shouldn't be too difficult to se a 1/12 -stop difference in the highlights; That's what my f/stop timer goes down to and I need and use it.

Doremus Scudder · Nov 23, 2017

RalphLambrecht said:
Oh, definitely; It shouldn't be too difficult to se a 1/12 -stop difference in the highlights; That's what my f/stop timer goes down to and I need and use it.

That's about 8%. I agree, that can make a noticeable difference in some prints. I can see a 5% difference at times. Like I mentioned above though, it's often easier and more repeatable to simply increase print development time for such small changes. E.g., it I have a print with a 30-second base exposure time and need to increase the exposure by 5%, that ends up being 1.5 seconds additional exposure; not undoable, but maybe a bit inconvenient, especially if I have complicated dodging and burning already worked out that I have to tweak by 5% too. However, an extra 15-30 seconds in the developer will do the same thing and I don't have to change anything in my already-worked-out print scheme. Extending developing time from 2.5 minutes to 5-6 minutes doesn't cause any fogging, but will effectively speed up the paper. You can pull a print anywhere in between, or pull one at 2 minutes if you've overexposed a bit.

As I'm working, I'll often make a couple of identical prints and pull them at different developing times just to see what that 5-10% difference makes. I find that easier than adjusting the exposure time by very small increments.

Best,

Doremus

CMoore · Nov 23, 2017

MattKing said:
I'm not going to disagree with you about something that works for you.
There are a number of factors that together make it advantageous for me to have a timer that at least offers 0.1 second increments:
- I see a significant difference between 1/6 and 1/3 of a stop exposure change;
- I make extensive use of the f/stop exposure table in "Way Beyond Monochrome";
- I reasonably frequently find myself in a situation where in order to lengthen the exposure time for some or all components of a print exposure past 10 seconds I would have to stop my enlarging lens down to its minimum aperture, which I prefer to avoid;
- I perceive a lot of benefit from being able to work within a consistent framework, and wish to avoid an approach where rounding a time off to the nearest second may have more of an effect on one part of a print's exposure than on another part of a print's exposure; and
- I particularly want to avoid a situation where round off variations end up being cumulative.

For many prints, I can happily get by without the 0.1 second increments. For some of my prints, the option is useful. For some reason, those prints that might benefit from it are often the most complex ones.

By the way, I agree that lamp warm-up and cool-down times are important, but I think having the option of 0.1 second increments makes it easier to take them into account.

Wow.....i would sure like to be in the darkroom with some of you guys.
Maybe it is because i am just a beginner, or maybe i will never be a Master Printer, but it is hard for me to imagine using tenths of a second.
There are many times, when i can hardly see a hard line on a test strip with a difference of 5 Seconds.....if you know what i mean.

Vaughn · Nov 23, 2017

CMoore said:
Wow.....i would sure like to be in the darkroom with some of you guys.
Maybe it is because i am just a beginner, or maybe i will never be a Master Printer, but it is hard for me to imagine using tenths of a second.
There are many times, when i can hardly see a hard line on a test strip with a difference of 5 Seconds.....if you know what i mean.

And don't forget about dry-down!...LOL!...without mistakes there would be no masters.

barzune · Nov 23, 2017

RalphLambrecht said:
Actually my RHDesigns timer really does. It's a function of the f/stop timer to wait for lamp and voltage stabilizer ramp up. With my Durst L1200, it made a visible difference especially in the test strips where the delay adds up otherwise.

Actually, http://www.darkroomautomation.com/fst.htm is the best that I've used, as a timer.
Far better than the RHD timer, from my experience.

pentaxuser · Nov 23, 2017

barzune said:
Actually, http://www.darkroomautomation.com/fst.htm is the best that I've used, as a timer.
Far better than the RHD timer, from my experience.

For anyone interested there is a very long thread that turned into a heated debate between Mr Lindan of darkroom automation and Mr Les McLean, who wrote the book "Creative Black and White Photography" and who was a famed printer and contributor here who championed the RH Designs meter.

pentaxuser

Doc W · Nov 23, 2017

Wow, thanks for all the responses! I will sort through all of this and ponder it. I use f-stop timing but for now, I am just rounding off. No disasters have ensued.

MattKing · Nov 23, 2017

CMoore said:
Wow.....i would sure like to be in the darkroom with some of you guys.
Maybe it is because i am just a beginner, or maybe i will never be a Master Printer, but it is hard for me to imagine using tenths of a second.
There are many times, when i can hardly see a hard line on a test strip with a difference of 5 Seconds.....if you know what i mean.

There are lots of times when I too have trouble seeing a difference between two segments that are 5 seconds apart.
But to pull an example out of just yesterday, I was printing some 5x7 prints and using some split grade techniques.
My two different exposures used Grade 1 and Grade 4. While Grade 1 was on, I dodged some areas. While Grade 4 was on, I dodged others.
Nine seconds of each yielded too light a print. Ten seconds of each yielded too dark a print. 9.2 seconds of each (plus a couple of extra seconds of low contrast burn) worked out just right.
I could have accomplished the same result with the lens stopped down another stop (to f/22) but the Grade 4 image on the easel was already pretty dim.

CMoore · Nov 24, 2017

MattKing said:
There are lots of times when I too have trouble seeing a difference between two segments that are 5 seconds apart.
But to pull an example out of just yesterday, I was printing some 5x7 prints and using some split grade techniques.
My two different exposures used Grade 1 and Grade 4. While Grade 1 was on, I dodged some areas. While Grade 4 was on, I dodged others.
Nine seconds of each yielded too light a print. Ten seconds of each yielded too dark a print. 9.2 seconds of each (plus a couple of extra seconds of low contrast burn) worked out just right.
I could have accomplished the same result with the lens stopped down another stop (to f/22) but the Grade 4 image on the easel was already pretty dim.

Hey Matt.....Thanks.
Yeah, OK.....so just my inexperience with Nuance/Details. I can see that sometimes those Tenths are probably Very Handy to have.
Thanks Again

Enlarger timer which does fractions of a second

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Enlarger timer which does fractions of a second

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