What do you mean by "preserve"? Museums have preservation protocols they follow for antique quilts, but I don't think you are asking about that. Light of any kind has a deteriorating effect on fabric, so I am wondering if you are thinking about the spray that protects fabric from UV light. This would not be a preservation technique used on an antique quilt. The only use I can think of for the UV spray is if you have made a quilt that you want to hang on a wall, but that is not meant to be preserved for generations. In that case I might be tempted to spray the quilt with the UV product just so that it would not fade as fast in its position that is exposed to light.
Edit: One method to help antique quilts survive longer is to hand baste bridal veil type fabric (I think it's call "illusion"?) over areas that are beginning to disintegrate.
Most steps taken to preserve antique quilts involve care in how they are cleaned and care in how they are stored.
Last edited by Prism99; 12-05-2014 at 11:18 AM.