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If white LEDs produce that much UV, what will it do to colors over time? I know sunlight and fluorescents will fade many materials.
I have a feeling that many of the problems in color rendering may be due to how different materials respond to the UV component of white LEDs.All white LEDs use blue/UV emitters that excite a layer of phosphors above the emitter, which then transform it into some variation on "white" (not unlike how fluorescent lamps work). The problem is that white LEDs release far more UV light than any tungsten lamps, or even many fluorescent lamps.All of that UV light causes different materials to react differently, although this isn't as evident to the eye because the white light tends to drown out this response. But many cameras will pick up on this, resulting in shifts and distortions in colors that may not be seen under normal conditions.
Interesting.LEDs emit relatively narrow wavelength (color) of light. While there are some LEDs which can emit light in the UV wavelength, it is usually very long-wavelength UV light, close to the visible violet/blue.Vast majority of the white LEDs (available in a wide range of color temperatures) utilize a common and inexpensive visible-light blue LED die coated with a phosphor which converts portion of the blue light to longer wavelengths light (yellow, red, etc.). The combination of the blue and longer wavelength light fools the human eye into seeing it as white light. But those LEDs emit very little (if any) light in the UV range. The temperature of the white light is controlled by the specific phosphor formula and by how much of the blue light is allowed to pass through the phosphor. Near-UV LED and phosphor based LEDs do exist, but are relatively rare.But a white LEDs which emit the higher temperature (more bluish white) light, can dramatically affect the color of the objects they are illuminating. But I don't think that there is much (if any) UV light in play.I would actually venture a statement that incandescent (especially halogen) light bulbs emit more light in the UV range than a blue die based white LED.Some good reading material is https://en.wikipedia.org/wiki/Light-emitting_diode#Phosphor-based_LEDsIt shows a graph of wavelengths emitted by a typical inexpensive white LED based on blue LED die and phosphor.There is very little light emitted in the UV region.
The problem with that graph is that it doesn't show emissions below 300 nm, and just because the graph is flat at 300 doesn't mean it stays that way, depending on the particular source. Although UVC (100 - 290 nm) from the sun is normally filtered out by the ozone layer, that doesn't apply to artificial sources.
Because it is a graph of a white LED which uses a blue LED die as a light source. There will be no emissions below 300nm from that LED die. There is no reason then to show that part of the graph.
How do we know that? Note that I edited my previous post, unfortunately after you replied to it. Check out that link. BTW, we are contaminating Lashedup's layout thread ...
Thread drift is totally fine with me. Some light reading...https://electronics.stackexchange.com/questions/290187/do-cool-white-leds-emit-uv-light
I suppose, then, that one must clarify and say, "near-UV" instead of just plain "UV" with respect to some "white" LEDs. But then there's anecdotal experience, such as one I had at a friend's home where he had some cheap white LED strip lights, and I noticed a printed graphic nearby that had some fluorescent inks in it lit up like someone was shining a "black light" ("true" UV) on it, when it didn't do so under normal room (tungsten) lighting. And it would be valuable (if someone hasn't done so already) to look at the behavior of various digital cameras under various "white" LED lighting conditions. I know I've been noticing some subtly odd color rendition myself...
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