Quote Originally Posted by Patrick Robert James View Post
I have been using glass carriers for the last 15 years. Combined with a laser alignment tool, the glass carriers deliver the best overall sharpness without a doubt. Cleanliness is certainly an issue, especially if you use a condenser enlarger, but it is worth it in my opinion. I would love to replace the lower glass in my Saunders 4550xl glass carrier with coated glass but haven't found any likely candidates yet. I doubt I would see much improvement at this point with the coated glass but every little bit helps.
You can get coated optical glass from Schneider Optics (Schneider's U.S. arm), cut and bevelled. For pieces in that size they will source it from their cinema/TV filter division. That's what I ended up going with in my Saunders 4550xl 4x5 carrier. In my 35mm carrier for the same enlarger I was able to use Schneider/B+W MRC "Multi Resistant Coating" glass cut from a clear B+W filter. As noted earlier, however, I can't see any difference in print quality compared with the non-coated glass that came with the carriers. And these modifications were not cheap.