black light + UV filters

I have a friend who wants me to take portraits lit by black lights only. This has me seriously wondering - do UV filters affect black light photography?

It depends on the precise nature of the "black light" sources and of the "UV" filter. It's entirely possible that a particular type of UV filter could block the UV light from the "black light" source.

Why do you ask? Do you use a UV filter on your lens(es) all the time for "protection"? If so, this would be one time to remove the filter.

SkipD wrote in post #15394179
It depends on the precise nature of the "black light" sources and of the "UV" filter. It's entirely possible that a particular type of UV filter could block the UV light from the "black light" source.

Why do you ask? Do you use a UV filter on your lens(es) all the time for "protection"? If so, this would be one time to remove the filter.

I've been seriously pursuing photography as a hobby for about a year now. When I started I left UV filters on for protection all the time. But I keep running into more and more situations where they are harmful to image quality, such as the topic of this thread or in scenes with light sources in the frame:

HTTP response: NOT FOUND | MIME changed to 'image/gif' | Redirected to error image by FLICKR

I have never once used a filter for anything but the special effect that could be provided by using the filter. In other words, I don't use filters for "protection" from anything. I still have every lens that I have purchased since 1967 and every one of them (though all have been heavily used in a variety of situations including on-track motocross photography) has nearly pristine glass in them. In other words, I don't feel that I need any "protection" beyond using common sense and proper lens cleaning techniques/materials.

SkipD wrote in post #15394179
this would be one time to remove the filter.

Then sell it on E-Bay.

I'm with Skip. Use hoods for protection.

your question pretty much answers itself.
When in doubt leave it off

'Black light' stimulates fluorescence in some things, which will then themselves EMIT visible light.

UV filter might filter out UV light from the source that enters the lens, but the UV filter cannot not filter out VISIBLE light emitted by the object.

It used to be that there was no UV filtration coating on the electronic flash xenon tubes of some flash units (Buff White Lightning had optional UV coating, for example). So the UV would cause optical brighteners in fabrics to glow, and the glow would be visible in the photo.

Hoods for me, too. But isn't there already a UV filter over the sensor?

PhotosGuy wrote in post #15395396
Hoods for me, too. But isn't there already a UV filter over the sensor?

No, there is an IR filter - other end of the spectrum. Silicon based sensors are naturally not very sensitive to UV.

They actually make special UV filters to be used in conjunction with fluorescence photography. As Wilt said the materials emit visible light. The filter cuts any reflected UV that would tend to degrade the image.

tzalman wrote in post #15396262
No, there is an IR filter - other end of the spectrum. Silicon based sensors are naturally not very sensitive to UV.

I believe that the IR filter also cuts out a lot of the UV. Then again, most lenses will absorb the vast majority of UV light as well.

When I had my 20D altered for IR I asked the guy doing it about adaptation for UV. He said there was a lot of interest from the forensic community, but that it had a lot more problems than conversion for IR. He said they were hoping to get something on the market in two years, but that was four years ago.

UV and IR are on opposite ends of the visible light spectrum and therefore a filter for one has no effect on the other. Blacklights produce UVA which the phosphors in the shirt convert to visible light. You can try photographing with and without the UV filter but the glow is from visible light which your eye sees. You camera sees more than your eye. That is why some use a filter to block it from a camera sensor.

ChunkyDA wrote in post #15401401
UV and IR are on opposite ends of the visible light spectrum and therefore a filter for one has no effect on the other.

Nope. UV/IR cut filters are quite common. LINK

Indeed, one might just as well say that red and violet light are at opposite ends of the visible spectrum, therefore a filter for one has no effect on the other. Which would make all ND filters impossible.

hollis_f wrote in post #15402014
Nope. UV/IR cut filters are quite common. LINK

That, in electronic terms, would be a band-pass filter which cuts off frequencies below a band of frequencies and above the same band.