Light damage can be incredibly invasive, though if you aren't aware of it and don't look for it, you might not notice that it has occurred. That is, you might have to look between the pleats or folds of a skirt to see the contrast in color. However, light damage isn't always so subtle...
Take this display of an 1860's crinoline, c. 1905 wool bodice, and possibly mid-20th century petticoat (firstly, not only is this arrangement extremely anachronistic, it was also awkward due to a piece of fabric wrapped around the crinoline but left open in back to display the crinoline...). The mid-20th century petticoat beneath, originally a bright coral, had faded to milky white where the striped fabric "skirt" exposed the crinoline.
|So much going on in one photo: the plastic "grass" of the display, the cage crinoline, the faded mid-20th century petticoat, the striped decorator upholstery fabric camouflaging as a skirt...|
|That streak of brown is actually dirt. The same dirt particles were found on the plastic bag covering the dress form.|
To cover up some of the silk shattering on the collar of this bodice, someone had wrapped a piece of wide black velvet ribbon around the collar and decorated with a brooch. When I removed the ribbon, I realized the full extent of the damage on this small subject; where the ribbon had overlapped, it retained it's original color, but where it was exposed to the sun, it had faded to a dull, dirty brown.