Light Duration Guidelines

National Museum of Asian Art – Smithsonian Institution Light Duration Guidelines for Exhibited Works of Art

The following guidelines were written by members of the Department of Conservation and Scientific Research and the Curatorial Department to establish a procedure for determining the length of time that works of art may be safely exhibited, providing for a balance of public access with long-term preservation.

• UV light in galleries is either completely blocked or will not exceed 75mW/L.
• Objects in poor condition in categories A – C may need their exposure duration or level curtailed as determined on a case by case basis by conservation assessment.
• The light category for an object is determined by its most sensitive material component.
• Exposure duration records for each object will be kept updated in TMS.
• If display time for an object is extended past exposure duration limit, there will be an extended rest time to compensate.

CATEGORY	MATERIALS	EXPOSURE DURATION LIMIT	MAXIMUM LIGHT LEVEL
A	Extremely fugitive pigments & dyes Highly degraded paper & silk 19th C & earlier woodblock prints w/color	3 months over 5 years	50 LUX (5 footcandles)
B	Watercolors Paintings and/or papers with organic pigments & dyes Pastels 20th C & later woodblock prints w/color Lacquer (incl. large ungilded kintsugi repairs & lacquer lids for ceramics) Textiles, including painting mountings	6 months over 5 years	50 LUX (5 footcandles)
C	Paintings with light stable pigments or carbon ink with no textile mountings Leather, dyed Pencil drawings Tempera paintings	12 months over 5 years	50-100 LUX (5-10 footcandles)
D	Ivory & bone Wood Leather, not dyed	24 months over 5 years	50-150 LUX (5-15 footcandles)
E	Oil paintings Stone Metals Glass Ceramics	Unlimited	300 LUX (30 footcandles)

National Museum of Asian Art- Smithsonian Institution Light Duration Guidelines For Exhibited Photographs

CATEGORY	MATERIALS	EXPOSURE DURATION LIMIT	MAXIMUM LIGHT LEVEL
A	Salted paper Albumen Cyanotype, Diazotype, Brownline, Van Dyke Photographs on resin-coated paper (pre-1980) Pre-2000 inkjet prints (and all Iris prints) Color photocopy (dry or liquid toner) Dye sublimation print (also called direct thermal transfer or D2T2) Dot matrix and Line plot	3 months over 5 years	50 LUX (5 footcandles)
B	Chromogenic prints (including Laserchrome & Lambda Dye-bleach prints (including Cibachrome) Collodion silver POP (Printing out paper)* Gelatin silver POP (Printing out paper)* Platinum & Palladium prints Inkjet prints (pigment and dye) Cased photographs* (daguerreotypes, ambrotypes, tintypes)	6 months over 5 years	50 LUX (5 footcandles)
C	Gelatin silver DOP (on fiber-based paper)* Collodion silver DOP (Developing out paper)* B&W photocopy (dry or liquid toner) Photogravure, halftone, collotype* (carbon or earth pigments ony – others category A) Carbon prints, Gum bichromate, Woodburtypes* (carbon or earth pigments only – others category A)	12 months over 5 years	50-100 LUX (5-10 footcandles)

*Anything that is hand colored, has a tinted base or Baryta layer, is on colored paper or mount, has other components should be in category A

Direct thermal transfer (type D1T1) and Autochromes should never be displayed- facsimile only.