The colour changes imposed by the application
of siloxane + 1%w/w SiO2 correspond to values lower the JND (Just
Noticeable Difference)limit of 2.3 [48],thus implying thatthe use of
these coatings do not affect practically the aesthetic appearances of
the treated silk specimens. However,the use of more SiO2 nanoparticles
(2 and 3% w/w) in the protective coating results in larger E*
values, according to the results of Table 1