What's the easiest and most affordable way for obtaining UV reflectance images?

petrochemist wrote:

Just to be clear, I was in no way indicating anything you said seemed wrong. I have a reasonable bit of experience with multispectral imaging, but very little with UV; everything you said sounded right for as much as I know.

ProfHankD wrote:

petrochemist wrote:

UV imaging is neither easy or cheap.

You said it all there... but....

I'll just mention that decoding multispectral information can be cheaper and easier than you'd think. ... extract the bands is primarily a matter of calibration and a bit of math.

I know it can be cheaper than I described, The OP want cheap & easy, so I thought suggesting a self modified compact & combining filters which might be the cheapest way wouldn't fit.

Your post does suggest I'd could get much better results from my poor mans UV set up if I learnt to process RAW better. Differencing is not something I'd ever considered I can see several potential applications for it in IR photography (where i already have a wide range of cut offs) I'm not a fan of extensive processing so even with that I'll probably never try it. I don't think any of my gel sample books have the wide range of long pass filters you mention - I'll have to keep my eyes open for other types...

It can help, but SNR is the big issue. If some channels are lots weaker than others, you get some channels with really poor DR. On the other hand, you can use filters to balance strength over a sampled spectrum, thus increasing SNR and DR. It just gets to be a pain.

Most of my experience with UV is in organic spectroscopy where I can clearly see how much UV is blocked by glass. The glass cells used for visual light have walls about 1mm thick, 2 of these walls effectively blocks all light below about 320nm, while UV quartz cells of the same dimension go right down to about 190nm about the point where air itself becomes opaque to UV..

Yup, quartz lenses are the "right answer." That's why old EPROM chips used to be so expensive: to get enough UV to erase 'em, they needed a little quartz window and a ceramic package to mount it in. UV is also scary in that bright UV lights are a serious health hazzard, so compensating for poor response by boosting light levels is a really bad idea.

I've played around with the works spectrometer for some of my photographic gear & have found a few of my lenses actually block all UV (blocking everything below 410nm) more effective than some UV filters. Without careful research the RAW files you try processing could have no significant UV data even in the 'unfiltered' shot.

Absolutely can't recover what's not there... and calibration can be a huge pain. Here's one example of what we did.

Of course, multiple shots are not suitable for some photography no matter what, so expensive filters that directly select the band you want can be the only option.