A strip of LightCheck ® is placed close to the artefact in order to get the same light exposure conditions. Every day, week or month depending on light levels, evaluate the Lightcheck by comparison of the colour to the calibration card. Choose the most similar colour, which will give a code i.e. 1S, 2S, 3S, 4S or 1U, 2U, 3U, 4U. Use this code to obtain an equivalent luminous exposure (ELE) from the tables below.

To estimate the annual exposure, multiply the ELE figure by 365 and divide by the number of days for which the Lightcheck has been exposed.

If a LightCheck® becomes white, the maximum luminous exposure has been exceeded.

LCU	Equivalent luminous exposure (lux h)
4U	75 000 - 100 000
3U	45 000 - 75 000
2U	30 000 - 45 000
1U	5 000 - 30 000
0U	0 - 5 000
LCU	Equivalent luminous exposure (lux h)

LCS	Equivalent luminous exposure
4S	Above 340 000 lx.h
3S	200 000-340 000 lx.h
2S	80 000-240 000 lx.h
1S	60 000-100 000 lx.h
0S	Below 60 000 lx.h

LightCheck® is a product of a European Commission funded project "A light dosimeter for monitoring cultural heritage - development, testing and transfer to market" (LiDo, EVK4-CT2000_00016).

• contains dyes that might migrate and produce stains or spots. Do not place in direct contact with an artefact and be aware of volatile organic compounds that may be emitted. Do not touch the surface of the strip.
• is not intended for monitoring high illuminance level such as camera flashes, nor has it been tested for long-term use over years of exposure.
• is not intended for use in an oxygen free environment