Interest in UV Meter / Integrating UV Meter

I am Nicholas Lindan, the proprietor and chief bottle washer at Darkroom Automation, web address below.

Darkroom Automation makes a precision enlarging meter that reads light intensity in 0.01 stop intervals over a 10 stop range. The present meter is optimized, as one would imagine, for use under an enlarger.

It is possible to provide a version of this meter that is instead UV filtered and calibrated to the range of intensities encountered in Alt-Process work. I imagine noon-time full sunlight would be full scale - or are there people working with brighter lights ?

It is also possible to add an integrating function to the meter. A full scale exposure would be 64 minutes in bright sunshine and the minimum exposure would be 4 seconds in sunlight - I take it this range would cover most alternative materials.

The meter, depending on the options, would cost from $110 for a simple light meter to ~$250+ for in integrating meter with remote probe and output for controlling a printing box, with possibly an exposure complete buzzer for outdoor use.

Obviously, there has to be interest in such a product before development can start - the market for traditional photographic equipment is small and developing products on speculation is not an available luxury.

If you are intereseted, would you be so kind as to reply to this post and/or send email to me at nolindan@ix.netcom.com

Thank you very much.

I wouldn't be interested but that's because I have to make my own tests depending on the day with my UV light. If I print within 12 hours of drying, I get different times than if I leave my paper to dry out fully for 24+ hours. I think this might be the case for quite a few Alt Processes as humidity is important and varies day to day so the exposure times ultimately vary based on that and beyond the UV light exposure times.
But I'm speaking as a lowly cyanotype maker which is more of a POP than DOP so I may be wrong for other processes.

Nicholas,

I would definitely purchase such a meter. I prefer whenever possible to print with the sun, and it would be very helpful to know that if my best exposure time is 4 minutes at noon, that by 2:30 pm it should be 4+X minutes. So an integrating feature would be extremely useful. Even in the cases where there's a need to do some initial exposure testing with a new batch of prepared paper, the meter would be very useful to get consistent exposures as a printing day went on.

Paul

I would also be interested in such a meter. Although I'm mostly a cyanotype person I am assembling the gear to get into carbon and as you cant see anything until after the event this sounds very useful. I'm not that fussed about turning things on and off or buzzers and such, but an integrating function would be nice. The price point sounds fair, and even if I only did cyanotype I'd look to purchase: my guess is the more expensive your process and the more it is a DOP the more useful the meter and the more useful extra functions would be.

I use a 1000 watt mercury lamp (essentially a point source) for carbon. I've never used the sun as a source so I'm not sure how the sun compares to my lamp in terms of output onto my neg. If I was sure I could use it as an integrator I would prolly be interested. So the sensitivity and range of the meter would have to be appropriate. My carbon contact print times vary between 2 minutes and 20 minutes with the mercury arc about 20 inches from the negative. The times vary based on the negative density, the sensitizer and it's concentration.

Would this meter be able to turn on/off the lamp? (Even low voltage low capacity contacts would work)

john



John

Most photoelectric sensors are not sensitive to UV although many are very sensitive to IR, so I don't think you can make a UV meter by filtering out the visible light.

Strict filtering may not be a good plan, but there are UV photodetectors like these

Chan Tran said:

Most photoelectric sensors are not sensitive to UV although many are very sensitive to IR, so I don't think you can make a UV meter by filtering out the visible light.

Click to expand...

Sorry, it's really not that hard to do.

I designed most of nuArc's modern exposure integrators: EZ-1, SM-2100 and EZ-Plus.

Which, though they are state of the art for graphic arts, are very crude instruments compared to the clinical analysis equipment my firm has designed.

hi
sounds intesting, I have often looked at this sort of thing: Dead Link Removed

and wondered if it could be adapted to our uses? (did some one say crude instrument)
maybe a couple of calculations from its readouts could give a starting point? just a thought

but yours sounds like a product that could be very useful, i would probably be in the market for a "simple light meter" model!

take care
pete

This is interesting to me, particularly if you can do something with a probe and a buzzer to meter daylight.

My usual albumen printing session starts around 10 am and I go to about 3 or 4 pm, depending on the season. I'm usually printing in indirect sunlight, and my best negs print at around 1 hour in indirect light, 20 min in direct sunlight. Occasionally, I might have a neg that prints 90min or 2 hrs in indirect light. Beyond that, you start getting strange artifacts like heat marks from the rivets in the print frame.

I usually have up to four prints exposing simultaneously. Are multiple timers a possibility? The way I do this normally is to use a small battery-operated Paterson process timer, which has three timers that can run simultaneously, and maybe I'll use something else like the stopwatch on my iPod for a fourth. I've also just marked the time on a sheet of paper for each frame, so that can work as well. I inspect the print as it prints out. An alternative to multiple timers might just be having a range of, say, 6 hours, where you could just start it at the beginning of the session and write down the start time to keep track of prints as the exposure begins, where the time would not be the literal time, but the time as it reads on a Metrolux timer, expanding and contracting with light output.

Nicholas,
I'd be interested in the simpler version. I make my prints using daylight. Since there are a lot of variables involved in the actual printing process itself (paper, chemistry, coating, humidity, etc.) having some sort of ballpark estimate of how much UV is present in printing in daylight would be most helpful. I've always thought that a version of a regular incident light meter would be of great help. The degree of precision and accuracy would not be as important to me as getting a good feel of just how much UV I have available to work with.

What could be really interesting is a handheld meter that could be used to measure UV in daylight for the purposes of exposing wet plate. Obviously, with wet plate materials not meeting any kind of ANSI standard, you couldn't use it as you would a regular meter, but it would be helpful to have something that could be used as a guide to get you closer to the mark.