Ultraviolet Photography: lighting

This post is all about lamps for UV photography.

Studio Photography. UV Black light tubes

If you work in a studio you will probably need just 2 UV fluorescent tubes. They are very cheap and you can mount them on any fixture for the normal visible light fluorescent tubes. Choose fixtures whose materials are not UV fluorescent. These tubes are very economical which means you can have more than two and have as much UV lighting as you need. Drawbacks: since the tubes are big there is no way to filter out their violet visible light and infrared light. This is not a big deal if your examination is limited to detect inpaintings (which will look darker than old paint and varnish). Though, the violet light will not allow you to appreciate the subtle UV fluorescence colors from old paints and varnishes.

My first UV lamp. Sirchie TigerUV

I do provide on-site art examination and documentation with, what I call, lightweight-low-cost-Ryanair-approved-luggage plan. So, being light, for my specific work, is mandatory. For a couple of years, until last month, I used the Sirchie TigerUV lamp. This is a spot light and is much more compact and lightweight than UV fluorescent tubes. It’s a 150W Mercury vapor lamp with internal ballast and long wave filter cover. Weight just 2,4 Kg and has a sufficient UV lighting: power density 4000uW/cm^2 at 15”. This is enough for  “light painting”. Indeed, since this is a spot light you don’t have uniform lighting over a painting so you have to quickly move the lamp during a long exposure, generally between 5-8 seconds, in order to have a final uniformly UV exposed image.

Sirchie TigerUV. My first portable UV lamp for on-site documentation. It has inside a mercury lamp and the VIS light cutting filter.

Fabrizio – Super lightweight. High-Flux 365nm LED

We made Fabrizio, the Ultraviolet (UV) lamp for Technical Art and Archaeology examination. Fabrizio is the UV lamp specifically designed for art and archaeology professionals. At CHSOS we tested a number of UV lamps already on the market but none was matching our standards. Fabrizio. is packed with features we need in daily art examination for conservation and scientific research.

Fabrizio, it’s a quite common Italian male name.  Used by the Romans the name Fabricius comes from faber, which indicated somebody that could make things, such as a craftsman.
Appius Claudius Caecus used this term in his famous sentence: Homo faber suae quisque fortunae (Every man is the artifex of his destiny).
At CHSOS we are more and more enjoying making tools for art examination. So, we named our new UV lamp, Fabrizio., another advanced tool proudly assembled and crafted in the CHSOS workshop.

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CLICK HERE for more info. Visit Fabrizio’s page.

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Features

UV LED Technology

Fabrizio’s core is a new UV LED emitting at 365 nm, the standard UVA spectral region used for UVF and UVR technical photography.

 

Intense UV lamp with superb high power.

Fabrizio has a stunningly strong Radiant Power of 14250 mW­ which distributes on a large surface. This is double the power of our previous lamp. Fabrizio can boost this strong power thanks to the new AlInGaN-based thin-film vertical LED chip technology. It has a grid of 10 series by 5 parallel micro LEDs for a total power consumption of 50W and 1500 mA operating at 32V.   AlInGaN-based thin-film vertical LED chip technology.

High-quality pure UV output

Fabrizio mounts a special filter to cut off all the visible light and allow only suitable UV radiation for perfect UVF photos. The UV LEDs produce UV radiation but also a lot of undesired visible light.

Hand-held and standard tripod adapter.

Fabrizio comes with and handle and an adapter for photographic tripods, just as a camera. How convenient! We work on scaffoldings and on-site, not just in laboratories, so we need a versatile handling of the lamp.

 

 

Spectroline MiniMAX UV-5F Short-Wave

UVF254 is the acronysm for UV fluorescence excited by a short wave UV lamp (254 nm). There are not LEDs at these short wavelengths so we still need to use mercury lamp. There are just small hand-held lamp on the market that deliver about just 5W. Though, it is fine to work with this low power since UVC radiation is harmful for eyes and skin, please read this before use UVC lamps.

I use a Spectroline MiniMAX UV-5F Short-Wave Hand-Held UV Lamp. UVC 254nm unit complete with LONGLIFETM glass filter. UVC light excites fluorescence that UVA lamps (365nm) don’t; some examples are given in the posts on madder lake and on postage stamps.

Spectroline MiniMAX UV-5F. A practical UVC (254) lamp.

UVR 254?

As a note, we cannot do UV Reflected with the UVC (254 nm) lamp since the digital camera detector can see UV light until about 350 nm.

 The Infrared tail

UV fluorescent tubes and mercury bulb lamps, such as Sirchie TigerUV have a sizable IR emission.

UV fluorescent tubes exhibit IR emission.

This IR emission doesn’t affect Ultraviolet Fluorescence photography, if the X-Nite CC1 filter is used together with the BW 420 (UV Fluorescence) and BW 403 (UV Reflected) to cut off that IR reflection. The UV 365 nm Nichia LEDs have another advantage here. They have a negligible IR emission.

Nichia 365 nm LEDs turn useful also for UV Reflected since they have a very small IR emission.