The Influences of Direct and Indirect Sunlight Intensity on Baseball Card Preservation

When planning to display your cards external conditions influence the amount of ultraviolet radiation from both direct and indirect sunlight. The time of year is an important factor when considering the intensity of UV rays. For the northern hemisphere ultraviolet radiation levels peak on June 21 with the lowest levels occurring on December 21.

The time of day is also important to consider as UV levels max out as the sun reaches its highest point in the sky - solar noon. The levels decrease to 50% of this peak 3 hours before and 3 hours after solar noon. Also influential is time of day.

Locations closer to the equator, the south, will receive greater amounts of ultraviolet light due to a more direct angle of the sun. The intensity of UV radiation increases by 4% for every 1,000 feet in elevation so be careful where you display your cards if you live in the mountains.

Here's a link to TEMIS - Tropospheric Emission Monitoring Internet Service which overlays the daily UV Index over the world wide map. This can help you to determine the relative UV light for your area compared to others and at different times of the year.

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