Pyroglaze Milk Bottles

Pyroglaze Decorated Milk Bottles

A Hertzler’s Dairy pyroglazed milk bottle from Elizabethtown PA, p4A item D9691542

Pyroglazing, or pyro for short, is a type of silk screening decoration introduced in the early 1930s to put colored labels on bottles. Pigments were fused to the glass during manufacture to create colored text and graphic designs. The process was quicker and more cost effective than using molds needed for embossing.

Thatcher Manufacturing referred to the process as pyroglazing. The Owens-Illinois Glass Company used the term Applied Color Labeling or ACL. The advent of colored labels was very appealing to the dairies and farms for advertising purposes making pyro decorated bottles the bottle of choice by the 1940s.