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I'm firing a 10" round of black 000100-0030 over another 10" round of teckta, on thinfire. I use a small piece of paper towel and BE's glass cleaner to clean the glass first. When I fire, I'm going up 400/hr to 1000, 400/hr to 1450, 9999 to 900, off. What I'm getting after firing are tiny surface dents, like a waterskipper (a bug that skates on the surface of a pond) has skidded across the surface of what was perfectly smooth, clean glass. The depressions aren't crud from my lid--just little dents like pin pricks. I've spread black powdered frit over the surface and refired; sometimes this helps, and other times I can't tell if I'm getting other little dents in different places. Frustrating. Probably a non-glass person wouldn't notice them, but I do, because i find they reflect light (like flakes of dichroic). Help, please.

Sometimes due to the manufacturing process, there are small pits squished into the glass.
If you can't see that prior to firing, it just may be small bubbles below the surface that break open during firing.
If it's the latter, there's not much you can do . . .

Thanks. What do you think non-glass people think when they see these? Sometimes, I try to get rid of the inner critic and say "other people" don't see what I see. Then other times, these little pits stand out so much in some light that I just can't stand them! Any feelings?

Yeah, I think they are faults. They make the piece a second.

I think it depends on the design--if the design calls for a smooth, shiny expanse of black, yep, they're faults. If the black is textured or sandblasted, not so much. OTOH, it does give the product that "human hand" look. I hate to say it, but I think it also depends on the price point of the work.

You can alleviate the bubble issues to some extent by firing black-side down (flip-n-fire), sandblasting or grinding to remove the surface texture produced by the kilnshelf contact, then flipping the piece black-side up and firepolishing. Whole lot more work, of course.

Thanks for the suggestions. I appreciate them all.

Cynthia, to your question about price point: about $160 and that includes the stand! We're a small town, so a typical gallery price point here is $200. I'm going to try the flip/fire technique. I chip open a hole in the black to make a mountain range; once fired, the mt range appears to be floating in a solid sheet of glass. Goes over well here. When I drop colored glass chips into the hole I've made, I like to try to hold onto the texture of those chips (post-firing); I'll lose that high/low texture in the flip/fire process. But if I can avoid the pitting on the black, I'd do just about anything.
Thanks for coming into the discussion. I always appreciate your input.

@LauraM:

Sounds like an interesting process - how 'bout a picture of a finished product?

Also: Do the pinprick holes you're talking about exist before firing? Are they a series of closely-spaced holes that appear in curving lines? Or do they only appear after firing? Are they [essentially] randomly placed?