Hi folks, I'm another newbie having just acquired a Crown 4x5, SN 942799 ('59 or '60?) a coupla weeks ago. I've been having fun learning all I can about these things. I immediately discovered that, as I'd read, that ground-glass screen is DIM! On a hunch (boredom, actually), I disassembled the panel and noticed a fine layer of grit between the GG and the Fresnel. (All the rest of the outfit was very clean). I don't know if the grit was dirt, broken down plastic from the Fresnel, or what.

After a careful cleaning and reassembly, I noticed a marked improvement in clarity while focusing - even without a loupe.

Now, if I could just brighten that puppy by 2 stops!