In article <825230296snz@x-ferret.demon.co.uk>, you say...

>Just accidentally touched my Shutter Curtain in my EOS 500. How do I >know if I have done any undetectable damage. Just in case it fails
>when I least need it/it's not taking quite as good pictures as an >un-touched one is?

If nothing is visibly bent, or not fitting as before; if it doesn't
leak light (fogging part of the film); and if it gives even exposures
at the flash synch. speed with flash, and at the top shutter speed
with available light, it is fine - don't worry about it.
Hope This Helps