In the book "Health and Safety in Welding and Allied Processes", 4th edition, Ed. N C Balchin (Published by Abington Publishing, 1991, ISBN 1 85573 032 4), the following comment is made (p.56)
"provided a matt finish is achieved, almost any colour is equally effective. Pastel shades are less depressing to look at ( than black) and may reduce eye strain by improving illumination at the work."