Preventing Discoloration in Films of Acrylic Artists' Media by Exposure to Ambient Light
| Main Authors: | , , |
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| Format: | Article |
| Language: | English Slovak |
| ISSN: | ISSN 0039-3630 |
| Online Access: | http://www.viks.sk/chk/studcon_2_03_95_102.doc |
| Abstract: | SUMARRIES. Acrylic polymer dispersions, regularly used as artists' media or varnishes, were monitored for the development of yellow discoloration under natural aging conditions for a period of two years. Films of a number of water-based acrylic artists' media were kept under visible light of either moderate (150 lux) or low (50 lux) intensity (cycled on 10 hours per day) and were compared to films kept in dark storage, which have been observed to yellow. Results after two years show that exposure to visible light at 150 lux effectively prevented film discoloration in a number of products, and seemed at least to slow the rate of yellowing in others. Exposure to low-intensity (50 lux) lighting was found to be less effective in preventing this yellowing. CONCLUSION. It is evident from these results and from prior studies that many acrylic dispersion films yellow slightly over time when stored in the dark. Moderate-intensity (150 lux) visible light seems effective at preventing or at least slowing the rate of discoloration in all of the acrylic dispersion films. Lower-intensity (50 lux) light exposure was less effective at preventing the discoloration. Some products assumed a constant level of discoloration intermediate between that of films stored in the dark and exposed to 150 lux illumination, while other films yellowed at a rate intermediate between the films stored in the dark and exposed to 150 lux visible light. Further, one product seemed unaffected by exposure to the low-intensity lighting. Previous studies showed that moderately intense light was capable of bleaching only a portion of the intrinsic yellow discoloration of a severely discolored acrylic medium [5]. This study shows that ambient-light exposure of a work containing an acrylic medium film, by exhibiting it or by storing it in an illuminated facility, may be capable of preventing or ameliorating the problems arising from discoloration. For artifacts that contain other light-sensitive materials that preclude prolonged exhibition at moderate (150 lux) light intensities, the results obtained here suggest that exposures to low light levels (50 lux) may prevent the discoloration in some products. Unfortunately, the effectiveness of this strategy may depend on the specific product that is present on the work. The casual and unintended light bleaching of acrylic media films on artworks may have fortuitously prevented the discoloration of the acrylic media from becoming a widespread problem warranting treatment, and one might surmise that yellowed acrylic media might be observed mainly on works that have been maintained in the dark or in very dim light. It would be prudent to be more aware of the presence of these acrylic films on artifacts, and to make decisions about the lighting of these works with this potential problem in mind. |
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| ISSN: | ISSN 0039-3630 |
