librarycompany: “No blueing required when this soap is used” This circa 1880 eleph
librarycompany:“No blueing required when this soap is used” This circa 1880 elephant-shaped trade card for Kirk’s Blue India Soap claims “no blueing required when this soap is used”. Blueing (or, bluing) is the process of adding trace amounts of blue dye while laundering white fabrics. As white fabric tends to yellow over time, the blue dye counters the yellowing to create the illusion of a brighter white. White fabric is often blued during its manufacturing process.No rewashing - always uniform. Kirk’s blue India soap. No blueing required when this soap is used. [graphic]. Imprint: UNITED STATES. [ca. 1880]. 1 print : lithograph printed in blue ink ; 9 x 14 cm. (3.5 x 5.5 in.) -- source link