Thom Rozendaal asks: "Why don't we use flowers to make pigments? I understand it would be hard to separate the biological matter from the pigments so maybe it would be possible to study how flowers produce these colors and recreate the processes in a lab? Has this ever been attempted before? Are there any pigments that are already made from flowers? It seems most are made of some type of mineral or something, and I guess I'm just worried we'll some day over-mine some of them as we are already doing with so many other things, whereas flowers are already being produced on a mass scale and are a renewable resource."
Thom, There are two main types of pigments in flowers: carotenoids and flavonoids. Scientific American says: "Carotenoids include carotene pigments (which produce yellow, orange and red colors). Carotene pigments are also found in vegetables, which is what gives carrots their colors. Flavonoids include
anthocyanin pigments (which produce red, purple, magenta and blue colors)."
Both of these are
natural organic pigment compositions that
fade quickly because the large molecules are easily broken by ultraviolet light. You can
make ink out of anthocyanin pigment, but it will be subject to photodegradation. People who collect dried flowers keep them pressed in books to protect them from ultraviolet light.
One organic pigment that has been traditionally been used as an artists' pigment or a vegetable dye is madder root, made from the dried root of
rubia tinctorium. The root pigment is "laked" which means "bonded chemically to a colorless, transparent, insoluble salt that often acts as its own mordant — which turns the dye into an insoluble pigment. The gum arabic in watercolors then binds this complex but chemically stable pigment to the paper." (
Source)
Natural organic pigments are rarely used in modern paints because of issues of lightfastness, so paint manufacturers use synthetic organic pigments or inorganic pigments.
This webpage explains more about that process.
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Scientific American:
Springtime Science: Exploring the Pigments in Flowers