UV handheld meter

I am looking for a handheld UV meter, my friend Ian Leake did make one but has decided not to proceed in production, I find
it very helpful and as we are teaching this summer beginner classes in Alt printing I would like to have a source to direct interested students.

There are several/many offered on Amazon, in the $150-250 price range. I’ve not explored them in detail, however, so can’t recommend or vouch for any in particular.

UV meters are fickle. The problem is that not all UV is created equal, and the differences are much more pronounced than they are in the visual spectrum. Differences in the spectrum itself if you're talking about sunlight (direct, shade, light clouds), transmission of optical elements (lenses/glass), the sensitivity of the target process (iron salts, silver salts, diazo, dichromate etc.) They all make very huge differences.

Then there's the issue of sensor spectral sensitivity. There's no agreed-upon standard of what the spectral response of a UV meter should be. Every sensor manufacturer just makes their own choices depending on what is technically feasible and what they believe might be useful. Take for instance these plots, that are the 3 sensitivity curves of a single AMS sensor and a low-end ML8511 sensor overlayed on top of each other:

Note how totally different they are, and in particular how the cutoff is at each end.

So you can meter UV, but what does the result tell you? In reality, you can only really say something sensible if you also know spectral distribution, the spectral sensitivity of the sensor, the transmissive qualities of the optical elements used and the spectral sensitivity of the recording medium. And even then you'll be juggling too many parameters to make really good sense of it.

This is not like a regular light meter for visible light photography, where there's an ISO standard and a reasonable expectation of uniformity across different meters. With UV meters, you'll be stumbling in the dark, although you may feel you know what's going on. In reality, you don't. It's perhaps even trickier than actually not knowing for sure what you're dealing with - at least you'll then be aware of the uncertainties involved!

The only applications where UV meters really make sense is where you can reasonably well control for the parameters I mentioned. In a photographic context, e.g. alt. printmaking in the sun or under different artificial light sources, the usefulness of a UV meter is very, very limited indeed.

BrianShaw said:

There are several/many offered on Amazon, in the $150-250 price range.

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I feel that's a lot of money for something that effectively has the dependability of captain Jack Sparrow's compass - but without the entertainment value.

Hi Bob. Here is something you might want to look at. Seems close to what you would like to explore. Or maybe its a bit mroe leabrate than what you may have in mind.

Hi Bob, just checking… have you abandoned this line of thinking?

Hi Brian.. no I do not want to build it myself as I have 4 thumbs on each hand. I own one of Ians system but
I teach workshops for beginner gum over pd and it would be great to pass on to others.

Hi Bob,

I have designed one for use in my darkroom and will be offering them for sale.
It uses an AS7331 and a temp/humidity sensor on a custom board.
It will be battery/usb powered and will be able to control an off the shelf wifi switch to manage exposures.
The sensor is on its own at one end of a cable, and the battery, screen and controls are on the other.
I'm still finalising the design and features - shall I keep you posted on my progress?
If there were particular features you'd want on there - it would be a good time to make suggestions!

Cheers

B

BenjaminAustin said:

Hi Bob,

I have designed one for use in my darkroom and will be offering them for sale.
It uses an AS7331 and a temp/humidity sensor on a custom board.
It will be battery/usb powered and will be able to control an off the shelf wifi switch to manage exposures.
The sensor is on its own at one end of a cable, and the battery, screen and controls are on the other.
I'm still finalising the design and features - shall I keep you posted on my progress?
If there were particular features you'd want on there - it would be a good time to make suggestions!

Cheers

B

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Hi Benjamin- I am interested to purchase one now to see how it works and spoiler alert I will be doing outdoor workshops for beginners learning alt printing and I believe a consistend hand held device would sell well.

bob

I trust that you'll be able to get in touch directly with each other to work things out - which is to say that regular threads we like to keep free of commercial transactions. Please feel free to get in touch through private messaging for this purpose. Thanks!

While @koraks has it right, if you do come to an agreement and end up using the device, feel free to share your experience here.

Would a Blak-Ray J-221 work for you? These seem to pop up from time to time.

Ah - Apologies. I didn't mean to flout the rules.

@Bob Carnie - I'll contact you privately.
@koraks - If I do end up making these - where would be the most appropriate place to let people know?

Thanks all

B

BenjaminAustin said:

@koraks - If I do end up making these - where would be the most appropriate place to let people know?

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As a paid Subscriber, start a Classifieds thread offering them for sale.

I've seen this thread pop up lately, wondering why anyone would need a UV meter. Giving some thought, I suppose the only practical photographic use that could possibly crop up. Perhaps being able to print cyanotypes in a contact frame on a daily basis using sunlight instead of an electric UV light bank, regardless of the weather? Maybe, if indeed such a meter was entirely insensitive to visible light, allowing a measure of accuracy in any daytime situation, sunny or cloudy. Is that the idea? Thank you.

F4U said:

I've seen this thread pop up lately, wondering why anyone would need a UV meter. Giving some thought, I suppose the only practical photographic use that could possibly crop up. Perhaps being able to print cyanotypes in a contact frame on a daily basis using sunlight instead of an electric UV light bank, regardless of the weather? Maybe, if indeed such a meter was entirely insensitive to visible light, allowing a measure of accuracy in any daytime situation, sunny or cloudy. Is that the idea? Thank you.

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Yes exactly.

I think many of us are using UV LEDs these days - and they're of varying build quality with output is not exactly consistent due to poor cooling design.
So unless you're careful - two exposures of the same time may yield different results.
One thing we do not need as alt printers is more variables...

And yes - exposing outdoors regardless of time of day or cloud cover is precisely the use case.

The sensitivity to visible light isn't so much an issue as the predominant wavelengths for UV sensitive processes are well below visible wavelengths.

Ultimately - you'd use a UV meter to calculate arbitrary 'units' of exposure that work for your process - and then be able to achieve repeatable quantities of light with good consistency.

Back in the day there was the Nuarc platemaker and a Stouffer's scale. Kinda big and I doubt now they even make the carbon sticks for it. Some of them had a curly bulb, but they lasted only so long and cost a fortune. I doubt now they even make them. Now I just use my Luna Pro with the incident cone. Better than nothing I suppose. Thanks for the reply.

F4U said:

Perhaps being able to print cyanotypes in a contact frame on a daily basis using sunlight instead of an electric UV light bank, regardless of the weather?

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Cyanotypes and all other UV-based processes, which is quite a range. The problem is that the 'regardless of weather' condition is a tricky one to meet even with a UV meter. See #3.
Another use case for a hand-held UV meter is to have a little more confidence in wet plate collodion exposures in daylight conditions, since most of the exposure will be constituted by violet and UV light.

BenjaminAustin said:

@koraks - If I do end up making these - where would be the most appropriate place to let people know?

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In addition to @MattKing's response, we're considering a place on the forum where small businesses can present a product. But this is not yet the case; for now, the Classifieds is the best spot if you're going to sell something.

F4U said:

Back in the day there was the Nuarc platemaker and a Stouffer's scale.

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These are still around but many people have been switching from their NuArcs to other exposure units. Anyway, this is offtopic.