Light Bleaching with Light Emitting Diodes (LED): Evaluation of Treatment Procedure and Bleaching Potential

Abstract

ABSTRACT Light emitting diodes (LED) offer a variety of beneficial properties for aqueous light bleaching of paper. They provide an intense light in a controllable setting while eliminating negative side effects associated with other light sources. Due to their low emission of infrared radiation (IR) and lack of ultraviolet radiation (UV), they can be placed closer to the object than any other light source. This multiplies the illuminance on the paper and thereby accelerates the bleaching process. The present investigation evaluates the properties of high-performance light emitting diodes for application in light bleaching treatments of various works of art on paper. A custom-built LED bleaching device with a maximum luminous flux of 30,000 lumens was used. The case studies demonstrate the relative ease of application of the LEDs for aqueous light bleaching. The treatment results illustrate the LED’s immense potential in quickly and consistently reducing local and overall discolouration of paper.