Those silks that cross over into other collectables areas, such as billiards, are desired by more people, and therefore demand a greater price. Other collectors collect the silks in series, and the Perez series is is particularly popular. Religious NF tapestries tend to sell for less, as they seem to have less interest at this time. Notably, most of the Neyret Freres woven silk pictures are in black and white, but some have been hand-painted to add splashes of color. I have no information as to how some came to be painted, and I would be interested to receive any information regarding this.
Condition is extremely important.
The ideal is to get the pictures in perfectly preserved, unframed condition. The next best condition would be framed in a way that has preserved its color and condition. Framed silks, exposed to light over many years, often become faded, particularly the colored ones. Many of these tapestries were purchased as souvenirs during wartime and may have been unknowingly damaged by the soldiers who handled them and left oily residue behind on the pictures. Others of these tapestries were placed in family scrapbooks, and were again touched again and again or damaged by acidic pages.