I’m not sure how widely these were available before the pandemic, but they’re now all over eBay due to the market that was created for testing germicidal wands and lights.

One very useful function of these it to test the ability of materials to block UVC light. By placing the test material (like my glasses) between the UVC source and the sensing surface it will indicate if the UVC is blocked. In my case all my glasses blocked UVC, which is reassuring.

The UVA test surface seems to respond right down to the near-UV LEDs in the 395-405nm range.

To find these on eBay use the keywords – UVC test card.
Price should be around 5 £$€ for a pack of 5 and not much more for a pack of 10.

Scientists say light pollution may be contributing to “worrying” declines in insects seen in recent decades.

In a UK study, artificial street lights were found to disrupt the behaviour of nocturnal moths, reducing caterpillars numbers by half.

Modern LED streetlights appeared to have the biggest impact.

There is growing evidence that insect populations are shrinking due to the likes of climate change, habitat loss and pesticides.

The “blue light” in LED lighting can damage the eye’s retina and disturb natural sleep rhythms, France’s government-run health watchdog said this week.

New findings confirm earlier concerns that “exposure to an intense and powerful [LED] light is ‘photo-toxic’ and can lead to irreversible loss of retinal cells and diminished sharpness of vision,” the French Agency for Food, Environmental and Occupational Health & Safety (ANSES) warned in a statement. The agency recommended in a 400-page report that the maximum limit for acute exposure be revised, even if such levels are rarely met in home or work environments.

The report distinguished between acute exposure of high-intensity LED light, and “chronic exposure” to lower intensity sources. While less dangerous, even chronic exposure can “accelerate the ageing of retinal tissue, contributing to a decline in visual acuity and certain degenerative diseases such as age-related macular degeneration,”

LED light can damage eyes, health authority warns
https://news.yahoo.com/led-light-damage-eyes-health-authority-warns-002221659.html?guccounter=1&guce_referrer=aHR0cHM6Ly9zY2llbmNlLnNsYXNoZG90Lm9yZy9zdG9yeS8xOS8wNS8xNS8xOTQ3MjU1L2xlZC1saWdodC1jYW4tZGFtYWdlLWV5ZXMtaGVhbHRoLWF1dGhvcml0eS13YXJucz91dG1fc291cmNlPWZlZWRidXJuZXImdXRtX21lZGl1bT1mZWVkJnV0bV9jYW1wYWlnbj1GZWVkJTNBK1NsYXNoZG90JTJGc2xhc2hkb3QlMkZ0byslMjglMjhUaXRsZSUyOVNsYXNoZG90KyUyOHJkZiUyOSUyOQ&guce_referrer_sig=AQAAAFLXsMsNb_S7NYr7JCRZFyO2IYitucpm_IAzlJYn6t9ZUFHK4IknvWUTT2tWL56x-_ltFuRLXt4kPdS82fCLzZMTKuh3rxuxsOlN-JQpMkszlq53jP9D6bK7bD14MymkkP-ugjNcqs3kQgyHRiG0lXwyys8xHonbXfc-NGD60kuk

Maisons-Alfort (France) (AFP) – The “blue light” in LED lighting can damage the eye’s retina and disturb natural sleep rhythms, France’s government-run health watchdog said this week.

New findings confirm earlier concerns that “exposure to an intense and powerful [LED] light is ‘photo-toxic’ and can lead to irreversible loss of retinal cells and diminished sharpness of vision,” the French Agency for Food, Environmental and Occupational Health & Safety (ANSES) warned in a statement.

Long-lasting, energy efficient and inexpensive, light-emitting diode (LED) technology has gobbled up half of the general lighting market in a decade, and will top 60 percent by the end of next year, according to industry projections.

LED uses only a fifth of the electricity needed for an incandescent bulb of comparable brightness.

The world’s leading LED light-bulb makers are GE Lighting, Osram and Philips

The basic technology for producing a white light combines a short wavelength LED such as blue or ultraviolet with a yellow phosphor coating. The whiter or “colder” the light, the greater the proportion of blue in the spectrum.

LEDs are used for home and street lighting, as well as in offices and industry.

That are also increasingly found in auto headlights, torches (flashlights) and some toys.

LED cellphone, tablet and laptop screens do not pose a risk of eye damage because their luminosity is very low compared to other types of lighting,

But these back-lit devices — especially when they are used at night or in a dark setting — can “disturb biological rhythms, and thus sleep patterns,” the agency cautioned.

Interfering with the body’s circadian rhythm is also known to aggravate metabolic disorders such a diabetes, as well as cardiovascular disease and some forms of cancer, noted Dina Attia, a researcher and project manager at ANSES.

For domestic lighting, ANSES recommended buying “warm white” LED lighting, limiting exposure to LED sources with a high concentration of blue light, and avoiding LED screens before bedtime.

A research study looking at paint degradation caused by illumination has been misinterpreted to throw LEDs into a bad light.

Museums and art galleries are often touted as excellent applications for high-quality LED lighting, provided that the necessary targets for characteristics such as color rendering can be met. Among the benefits provided by LED lighting, alongside energy savings, is the lack of ultraviolet (UV) and infrared (IR) radiation. The absence of IR means that the LED light source does not produce heat, and can be placed close to the piece to be illuminated. Meanwhile, the absence of UV is said to prevent degradation of potentially sensitive materials.

However, many different materials are used in works of art, and each can respond differently when exposed to different wavelengths of light. In fact, one set of scientific results looking at yellow paints used over a century ago has resulted in some very bad press for LED lighting. But the link between these results and LEDs is tenuous at best.

For example, The Independent, a daily national newspaper in the UK, published an article entitled “Sunflowers wilt: Van Gogh’s masterpiece is slowly turning brown as a result of exposure to LED lighting.”

But on closer inspection, it turns out that the scientists didn’t actually use LED lights at all. Instead, they used a high-intensity Xenon lamp (Cermax 175W) in combination with various wavelength filters.

The link between the results and LED lighting originated with a press release from the University of Antwerp in Belgium, entitled “LED lights may be bad for Van Gogh paintings.”

Soraa, the California-based LED lamp manufacturer, has looked into this issue and provided further technical analysis. Soraa said it was responding to “erroneous reports of painting degradation by LED lamps” and said that the study had been “loosely and irresponsibly associated with LED lighting.”

Degradation of the paint samples was observed under intense irradiation, said Soraa, amounting to more than 1000X the values used in conventional illumination, when the “blue” (335-525 nm) filter was used.

Whatever the reason for the degradation observed in the Van Gogh paintings, it is clear that the people responsible for illuminating art and museum pieces need to be aware of potentially detrimental effects of using certain light sources.