Early textiles were dyed/printed with natural products. Dyes were extracted from roots and stems, leaves, berries and flowers as well as some insects and shellfish. Indigo has a natural affinity for cotton, most other natural dyes require a mordant for printing. ( A mordant is metal salt which binds with the coloring agent in the dye and also the cotton fiber. Some mordants are alum, iron, tin, copper and chrome). The mordant/dye combination forms a 'lake' of color which permeates the fiber.
The dyes are seen on the back of the fabric...in a slightly different intensity.
Todays' fabric are usually printed with pigments. The colors are bonded to the fibers with resins. The result is a printed fabric whose color is resistant to fading on laundering but which does not show on the the back side of the fabric.
The dyed example is from the Dargate book, c. 1830. The pigmented sample is a reproduction of a Dargate Indigo.
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