ATM Blacken bevel?

[Sjoplinh@aol.com]

I saw a recommendation recently to blacken the primary's bevel, if it's
exposed.

I went to all the trouble of bevelling off my little (1 mm) TDE, just to avoid
masking or painting it.  Now I hear I should blacken the bevel, anyway.  Boo -
hoo... The reason I chose not to paint the TDE is because I figured cleaning
the mirror with alcohol / acetone would remove the paint... not only requiring
re - painting, but... maybe getting some on the primary face, then how do you
know when it's all off?  Couldn't traces be left across the face that would
reduce reflectivity, but not be readily visible?

How valuable is blackening the bevel as far as improving contrast?

BTW, I ended up coating the mirror with shellac before bevelling off the TDE.
That worked fine, but one caveat: You don't want to use loose abrasive, e.g.
emery and a piece of glass, with this method.  I did one round of that, looked
at it under the scope, and found that the abrasive was sure enough "piling up"
and removing the edge of the shellac. No damage done, but assume it would
roughen the edge eventually.  Whetstone or equivalent and frequent rinsing
only.

The shellac came off fine with repeated alcohol soaks. I got a little
impatient and hurried things along (gently) with some cotton swabs.  I hope
someone can tell me that Pyrex is harder than AlO overcoats, which I've heard
must be babied to no end.

Scott