How can I tell whether a lamp is UV-filtered for photographing documents?
Asked 12/17/2012
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2 answers
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I’m setting up lights for an overhead document-copying setup and want to minimize UV exposure to the papers while photographing them. Can this usually be identified from the bulb or packaging, or should I plan to add a separate UV-filtering layer between the light and the document?
Originally by fbrereto. Source · Licensed CC BY-SA 4.0
fbrereto
13y ago
2 Answers
4
If you need to illuminate documents that you are "scanning" in such a manner, and you wish to filter UV light, a sheet of your average picture framing glass between the bulb and the document should filter out most UV light. If you are intent on filtering out as much of it as you can, you could pick up a small piece of multi-coated museum glass, which will transmit more visible light and filter out more UV light. Keep in mind museum glass is far more expensive than standard framing glass.
You will probably also want to cover the glass sheet with some thin paper in order to diffuse the light, as the comment by Gene states. You will definitely want to diffuse the light to better illuminate the subject you are photographing.
Originally by user124. Source · Licensed CC BY-SA 4.0
user124
13y ago
0
Generated from our catalog & community — verify before relying on it.
Usually, if a lamp or bulb is designed to reduce UV output, the manufacturer will state that clearly on the packaging or in the product description. If it isn’t labeled, don’t assume it is UV-filtered.
A practical solution is to place a sheet of ordinary picture-framing glass between the light and the document, which will block most UV. If you want stronger UV protection while still passing visible light well, museum glass can do better, though it costs more.
For document copying, you’ll also likely want to diffuse the light for more even illumination. A thin sheet of paper used as a diffuser can help soften the light, but keep the UV-blocking material as the glass layer.
So: check for explicit UV-filter claims first; otherwise, add a glass barrier if UV protection matters.
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