Question about Flashed Glass

We're all just wild about Harry (Clarke)

Q: When you blast off a flash, do you prefer to then trace and matt on the blasted side or on the clear side?

or get down and dirty and trace into that rough stuff, but keep the images "registered"...

WWKLD??

WWHCD????

A: Well, Harry Clarke would acid etch the flash with hydrofluoric acid leaving the surface brilliant and eminently paint-able. I mix it up. If the panel is going to be viewed at very close range and I am concerned with "registration" then I put the flash to the inside sandblast it off and fire polish it in my kiln. What is fire polishing you ask? Getting the glass hot enough to melt down the rough surface left over from sandblasting. Usually 1350 with a 20 minute hold will do the trick. Watch out for shrinkage. The result is not as nice as acid etching but a lot more manageable in my studio step-up. (Read - Sigh, I would prefer to acid etch). When registration is not a concern then I put the flash to the exterior, sand blast and paint on the smooth, non-flashed side.