a deep dive into the deepest blue

Natural Indigo

A blue-hued dye produced bya fermentation and oxidation processthat converts the glycoside indicaninto the blue-hued pigment indigotin

Historically, indigo was produced using one of several species of the Indigofera plant family or, to a lesser extent, tropical mollusks like the Hexaplex Trunculus sea snail. Each source of natural indican compound is known for a particular character of dye: Trunculus snails for the deep Tyrian Purple color of Imperial Rome, the Indigofera Tinctoria plant for a tendency to quickly develop a patina like that of sea-worn ceramic.

Triumph of Tradition

Today, nearly all indigo is derived from petroleum. These synthetics do contain indigotin and are therefore real indigo. In fact, they are nearly pure indigotin, roughly 400% more concentrated than most natural dyes, yet they fail to deliver the depth and intensity of natural indigo—precisely because they are entirely too pure, lacking the complex profile of flavonoids found in nature that enhance indigo pigments.

Natural Indigo - Herbal Remedy for the Blues

Alchemy & Artistry

In addition to plant-derived indigo’s color-enhancing flavonoids which add traces of aquamarine and violet to its primary deep blue hue, fermentation leaves its indigotin compound chemically unstable and prone to random and unpredictable oxidation—this accelerates patination and brings-out tints and shades that highlight existing tonal shifts already present in organic materials such as leather. The wayward chemical properties of natural indigo enable this dye to produce an extraordinary range and depth of color unmatched by any single pigment. However, this unpredictability means effective administration of this dye is more art than science.

Natural Indigo Vat Overdye

Vat Overdyedby Hand in the U.S.A.

Our Chromexcel Roughout has been overdyed in an exclusive formulation of natural indigo, alkali salts, and rainwater that imbue the pigments with an affinity for the oil-rich leather. This is all done not according to any recipe, but by the hand of a master “dexter” familiar with the reactive nature of indigo dyestuffs exposed to complex organic compounds, such as those present in Chromexcel’s tannage. Once dry, the pigments stabilize, preserving the rich color of the natural dye without compromising oils that protect the leather.

Natural Indigo Vat Overdye

Natural Indigoand nothing but

Even the smallest amount of indigo will easily overpower nearly any other dye, so indigo vat dying is never done with equipment shared with other pigments–and that goes for everything from steel vats to rubber gloves. This means indigo-dyed materials tend to be boldly saturated and vibrant compared to those dyed with pigments that share equipment. The depth of a natural indigo is thus limited only by the physical properties of the raw materials and the skill of the dexter.

Trench Boot-Natural Indigo Chromexcel Roughout Patina

Above: Two years of hard wear

Wabi-Sabi

Beneath its indigo-overdyed layer, the Chromexcel roughout retains its natural color, like a tea-core leather, but inside-out. Unlike tea-core, which can take a year or more before the natural core begins to surface, the roughout napp will begin exposing natural tones without superficial scratches or longterm wear.