Im looking to start alternative processes, beginning with cyanotypes, and perhaps going beyond that.
My plan is to use a halogen work light as a UV source.
From what I understand, the output of these varies over the life of the lamp, and even to some extent of the duration of a printing session, which seems to call for a UV light meter.
Does anyone have a suggestion for a reliable light meter that is not too expensive? (a relative term, I know.)
Is it possible to save any significant money by trying to make a DIY version wthout sacrifgicing reliability?
And does anyone have any thoughtds as to whether here would be a better choice for a light source?
Ordinary glass blocks UV radiation of wavelengths shorter than 360 nm. This is barely into the UV region which starts at 400 nm. For shorter wavelengths fused quartz must be used instead of glass. For any UV source you need to check its output before use.
Probably the best source of UV is from a mercury arc lamp such as used for tanning. Once it warms up its output should be quite constant. They typically have a very long life. This would remove thae need for any metering.
Have you looked at alternative process sites they have some useful information?
You will be far better off, and richer, to buy, or build a good UV source instead of the hot, low UV output work light. Then you won't need the expensive meter.
Google "alternative photography" and you will be directed to more good information than you can absorb in a short time..
I don't think you need a UV meter. All you have to do is run tests with your alternative process along with your UV light box. If the output of your box is consistent, your test prints should reveal the speed of your materials. Just take good notes. I did my test on my UV light box with a Stouffer step wedge and a densitometer. Just like with any photographic material, the aim is to expose the minimal amount for the maximum density in the darkest part of the print. My LED UV light box for cyanotypes has been consistently 7 minutes with my brand of OHP film if you want to go that route.
You don't *need* a UV meter, but you might find one useful. I have been making alt prints of various kinds for many years, and I just got one of these: Dead Link Removed
My UV tubes are very consistent, but I think I will find some creative uses for this (for example: moving between sun and BL tube exposures).
Back in the good old days, when I was in prepress and working the "rubber stamp" department... This is what I used to check the UV output of fluorescent tubes in the photopolymer platemaker.