Wavelength Dependence of Light Induced Changes in Reflectance Spectra of Selected Dyes and Pigments

ABSTRACT

Historical objects in exhibitions can be subject to light induced damages resulting in a shift of color and brightness. Besides certain ambient influences the main factor governing these effects is the spectral irradiance applied to the surface. As the photochemical efficiency of electromagnetic radiation depends on its wavelength it is desirable to know the effect of individual spectral components in order to estimate the damage potential of a certain light source. In this work the modifications of the reflectance spectra of 40 dyes and pigments relevant in historical book illumination resulting from irradiation by eight narrow band LED light sources are presented. The LED wavelengths cover the visible part of the electromagnetic spectrum. Based on the measured reflectance spectra, color values are calculated and their evolution is studied as a function of the amount of radiation applied.

KEYWORDS:

• Light induced damage
• spectral reflectance
• pigments
• dyes
• monochromatic irradiation
• light sources
• damage potential
• wavelength dependence

Disclosure statement

No potential conflict of interest was reported by the authors.

ORCID

Beate Villmann http://orcid.org/0000-0003-2819-7055

Additional information

Funding

This work was supported by a grant from the German Federal Government Commissioner for Culture and the Media on the basis of a resolution passed by the German Bundestag and the Cultural Foundation of the German Federal States.