Annual UV Exposure Limits for Baseball Cards

The intensity of visible light is measured with a light meter which gives a reading in lux. 1 lux = 1 lumen per square inch.

Here are some examples of lux at the surface area of a baseball card under different conditions:
• Direct Bright Sunlight – 100,000 lux
• In Shade of Direct Bright Sunlight – 10,000 lux
• Direct Bright Sunlight in a Room – 5,000 lux
• Typical Florescent Lighting – 300-500 lux
• Typical 100 Watt Bulb at 3 Feet – 100 lux
• Museum Lighting – 50 lux
• Candle at 1 Foot – 10 lux
• Full Moon – 1 lux

For most vintage collectables ranges vary from 50,000 lux-hours for sensitive materials to more than 500,000 for more durable materials such as wood and leather. One recommendations called for a max of 150,000 lux-hours for colored photographs and color work on paper. This seams like a reasonable proxy for new or modern baseball cards.

The Illuminating Engineering Society of North America call for a maximum illumanence of 50 lux and a total exposure of 50,000 lux-hours for water color works. Since these materials are more sensitive I would presume that these are solid guidelines for vintage baseball cards. Reciprocity is the principle by which exposure time is multiplied by exposure intensity to determine total exposure. In this example you would want to limit your baseball cards to 1,000 hours at 50 lux.

Ways to reduce lux-hours per year:
• Lighting - museum quality lighting with lower microwatts per lumen
• Display – use museum glass that filters most UV radiation
• Exposure – limit exposure by displaying in rooms with no natural light or rotate the cards in your baseball card display periodically

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