Warning: Urushi And Uv Radiation

[OCArt]

Just found this and thought I'd pass along the warning. http://www.hakuminurushi.com/conservation/light.html

 

"Urushi lacquer is very sensitive to light, especially in the range considered ultraviolet light (below 400nm) and can be damaged by overexposure. Avoid exposing lacquerware to direct sunlight or other sources of ultraviolet radiation such as halogen lamps, black-lights and sterilization chambers and avoid exposing lacquerware to strong or direct light over long periods of time.

Avoid Light Exposure

Avoid Strong or Direct Sunlight, Ultraviolet Light and Long Exposure to Light

Unfortunately this fact is urushi's greatest weakness and is one that any owner of lacquerware should know and understand. Overexposure to light can cause noticeable discoloration and loss of lustre and gloss of the lacquer surface. Severe overexposure (especially to that of wavelengths 365nm or less) can cause additional damage including cracking or crazing of the surface, and as a result, exfoliation of the lacquer layers. This type of damage typically will not happen in an average setting but it is clear that care should be taken to prevent such irreversible damage.

Preventing damage from over exposure to the most damaging range of ultraviolet light is not a difficult task. Simply avoiding the display and use of lacquerware in and around the strongest sources of this range of light will prevent any severe damage. Sunlight remains the strongest source of ultraviolet light will typically be encountered. Avoid using lacquerware outdoors during daylight hours and do not place or display lacquerware in front of a window or in other places where strong or direct sunlight may enter. Halogen lamps may still be encountered frequently for display lighting in stores and sometimes in the home. Although halogen lamps typically come with UV filters which effectively block a large portion of the emitted ultraviolet light, due its strong intensity and high temperatures, it is still recommended to avoid displaying lacquerware under halogen lamps. In is inadvisable to use a halogen lamp with its UV filter removed. Lacquerware should also never be sterilized in a UV based germicidal or sterilization chamber as these use strong doses of ultraviolet light in the most damaging spectrum (UV-C, 280-100nm) to kill pathogens. Other sources of ultraviolet light include various less common light sources such as high intensity discharge lamps, specialty gas discharge lamps, and certain high intensity LED lamps. Most of these particular sources of ultraviolet light would not be encountered in a normal setting, but should be avoided should the case arise.

Ultraviolet light, however, is not the only portion of the spectrum that may damage urushi. Although the level of damage is drastically reduced, light in the visible spectrum can also noticeably deteriorate a lacquer surface. Frequent, extended exposure to the visible spectrum can cause a noticeable change in color and a reduction in luster and gloss in as little as 6 years for transparent or lighter colored lacquer surfaces and 21 years for black lacquer surfaces1. In practice, this type of damage is difficult to achieve in a typical household setting, but it becomes understandable when it is suggested that urushi should not be put on constant display and be illuminated only when they are actually being viewed. Maki-e lacquerware with a heavy layer of exposed metal powder covering the entire surface, as frequently seen in kintsugi repairs on ceramics, will experience very little or no damage from this type of exposure.

Heat is also a factor in damage caused by lighting excessive heat over long periods of time also contribute to the surface deterioration in lacquerware. If lighting must be used in close proximity, only low temperature lamps such as fluorescent lamps should be used and they should be arranged to reduce the amount of heat as much as possible.

However, at times, unintended damage may still occur. If the layer is severely damaged to the extent of cracking and flaking, little can be done to restore the surface and the only measure that can be taken is to solidify the oxidized lacquer layer and prevent additional damage. However, slight damage can be reversed to some extent. Although changes in color may be permanent, a restoration treatment will typically be able to bring a slightly dulled urushi surface back to its original shine.

Nevertheless, this type of restoration effort is best avoided in its entirety and steps should be taken to prevent its need. Avoiding overexposure to light is most important, but a treatment of the lacquer surface is suggested approximately every 20 years. This treatment involves a thorough cleaning, inspection and a re-impregnation of any oxidized or damaged areas with lacquer. However, this type of treatment is not necessary to maintain the beauty of a piece of lacquerware.

With proper care, damage caused by overexposure to light is not something that will be encountered over the lifetime of a piece of lacquerware, but knowing how to avoid this damage is important to prevent it from occurring at all.

References:

• Ogawa, Toshio; Arai, Kazutaka; Osawa Satoshi, "Light Stability of Oriental Lacquer Films

Irradiated by a Fluorescent Lamp." Journal of Polymers and the Environment 6:1 (1998): 59-65

• Webb, Marianne, Lacquer: Technology and Conservation (Oxford and Boston, 2000)

• Araki, Tadashi; Sato, Hisayishi, "Relationships Between Exhibition Lighting and Discoloration of

Lacquered Wares." Scientific Papers on Japanese Antiques and Art Crafts 23 (August 1978): 1-24

1. JRank.org Arts, Conservation - 1. Introduction., 2. Urushi., 3. Insect and associated lacquers.,

http://arts.jrank.org/pages/9696/III-Conservation.html (21 July 2010)

[zaddick]

It's the long periods of time that is the issue. Regular use indoors or out is not going to create damage. Leaving pens in a sunny window for a long time will or storing them under constant lighting.

[ethernautrix]

I've taken this information as well-known for granted, so thank you for sharing it.

[Tseg]

I would like to see an example of an overexposed Urushi pen. I’m sure there may be examples of Urushi display pottery with such issues, but have never seen such with a pen.

[PAKMAN]

Not just sun light, if your office has florescent lights and the pen sits in constant exposure it could also lead to issues. It certainly can cause inks to fade away to nothing!

[BaronWulfraed]

Most, if not all, halogen reading lamps include a UV shield lens over the bulb. No doubt some still gets out, but should be much reduced.

[ethernautrix]

I would like to see an example of an overexposed Urushi pen. Im sure there may be examples of Urushi display pottery with such issues, but have never seen such with a pen.

I don't have a picture, but I saw a friend's Nakaya that he usually carried in his shirt pocket, the top of the pen exposed to the near-constant sunlight where he lives, and the cap was unequivocally faded and dulled.

 

Seeing that ensured that I wouldn't be lazy about protecting my Nakayas.

[Karmachanic]

UV is harmful to humans. Cataracts and skin cancer for instance.

[zaddick]

I would like to see an example of an overexposed Urushi pen. Im sure there may be examples of Urushi display pottery with such issues, but have never seen such with a pen.

I hBe a Namiki with this issue. Parts of the black finish look dull or foggy, like some grime you should be able to wipe off but cannot. The pen was a store dispLy for a long while. I can't post photos from my phone easily, but I think I have some still.

[larsm]

On 3/30/2019 at 11:40 PM, zaddick said:

I hBe a Namiki with this issue. Parts of the black finish look dull or foggy, like some grime you should be able to wipe off but cannot. The pen was a store dispLy for a long while. I can't post photos from my phone easily, but I think I have some still.

I would be very interested to see such a photo!

[wspohn]

Interesting article.  Glass does filter UV-B but not UV-A.  I have an urushi coated phono cartridge on one of my turntables, which is fortunately not located near a window.

[Karmachanic]

Besides humans and urushi, UV light can also damage celluloid and Ebonite.

[wspohn]

36 minutes ago, Karmachanic said:

Besides humans and urushi, UV light can also damage celluloid and Ebonite.

 

Is the 'fogging' of ebonite an oxidation reaction or photocatalyzed?

[sansenri]

I would also assume that urushi relies on this characteristic for some of its features (such as the rising dragon).

Certainly I would avoid exposing such pens to strong light (uncoated ebonite suffers similar damage, btw)

[sansenri]

1 hour ago, Karmachanic said:

Besides humans and urushi, UV light can also damage celluloid and Ebonite.

oops, noticed you just said that

[Karmachanic]

11 hours ago, wspohn said:

 

Is the 'fogging' of ebonite an oxidation reaction or photocatalyzed?

 

Oxidation is my understanding.