5 1920s engineering plates 23x17 Pittsburgh Plate Glass Co. Easyset Storefront designs

Engineering Plan Plates, Pittsburgh Plate Glass Co. EasySet All-Metal Storefronts, five 23 by 17 plates, suitable for framing. Plate 1 has a double-crease where it was misfolded but all would present well (better matted than on my fridge, as pictured) when mounted, or even as is. A couple of minor tears to folds, one creased corner, paper is slightly yellowed but no foxing to speak of. (It's on watermarked, bonded paper, so high quality.) This company evolved into what is now PPG, so it's still around, just more chemicals than glass. Undated, but the text style (and other material in my archive) puts it pretty clearly in the 1920s. Comes with the original mailing envelope and index of plates; not a repro, and they've never been digitized to my knowledge.