Light damage calculator

The light damage calculator provides an estimate of the fading of colours exposed to light, based on the best available data. There are several sources of uncertainty:

  • ambiguity in the identification of the colourants in the object
  • imprecise fading data for that colourant
  • inaccuracy in the representation of colours on a computer screen

Despite these uncertainties, the calculator can show the wide sensitivity range of coloured objects and the influence of exhibitions on the future appearance of collections. Original and faded colours are presented as patches on the computer screen. Since some computer screens and many computer projectors, do not distinguish small changes in colour, the height of the faded colour patch also changes in proportion to the amount of fading.

There are three different uses for the light damage calculator. The three calculators are the following:

  1. Fading of a single colorant

This provides an estimate of the fading of a single colourant under a single set of conditions. For those interested in the scientific measurement of the fade, the colour difference, ΔE, is also provided.

  1. Fading of a single colorant in three different scenarios

This provides a side-by-side comparison of the fading caused by three different exposure scenarios.

  1. Fading of a collection of coloured objects

This presents the fading of collections of colours. These may be collections in the conventional museum sense (such as a textile collection or a watercolour collection), or they may be collections of colours in a particular type of object (such as the three dyes used in a particular kind of colour photograph).

Want to know more?

View a Tour of the Canadian Conservation Institute’s Online Light Damage Calculator by Stefan Michalski, Senior Conservation Scientist, Preventative Conservation Services. Presented by the Connecting to Collections Online Community.

For further information on the topic of light, see the web page Agent of Deterioration: Light, Ultraviolet and Infrared . For problems or mistakes concerning the content of the Light Damage Calculator, please contact CCI.

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