https://wiki.hacksburg.org/index.php?action=history&feed=atom&title=OrganicDye OrganicDye - Revision history 2026-11-06T17:40:13Z Revision history for this page on the wiki MediaWiki 1.43.8 https://wiki.hacksburg.org/index.php?title=OrganicDye&diff=1782&oldid=prev Dan Barlow: Organic Colors 2022-09-30T23:21:16Z <p>Organic Colors</p> <p><b>New page</b></p><div>Natural materials have been used to color objects for 40-170 thousand years (that we have [https://en.wikipedia.org/wiki/Pinnacle_Point evidence] for). &lt;br&gt;<br /> The observed ancient pigments:&lt;br&gt;<br /> <br /> [https://en.wikipedia.org/wiki/Iron(III)_oxide &#039;&#039;&#039;Iron&#039;&#039;&#039;] based natural colors&lt;br&gt;<br /> Formula Fe&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt; - three oxygen atoms bound to two iron atoms, AKA &#039;&#039;&#039;ferric oxide&#039;&#039;&#039;.&lt;br&gt;<br /> In this formula it can crystallize into Hematite, grey to black in color, and commonly found in rocks and clay; when weathered it can become Maghemite, as a brown to yellow color often found in sediment layers; or grayish blue or even white.&lt;br&gt;<br /> When hydrated (Fe&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt;*H&lt;sub&gt;2&lt;/sub&gt;O) it can form complex minerals of varying color.&lt;br&gt;<br /> * Red Ochre is hydrated ferric oxide and has additional Hematite.<br /> * Yellow Ochre is hydrated ferric oxide.<br /> * Hematite is dehydrated ferric oxide.&lt;br&gt;<br /> [https://en.wikipedia.org/wiki/Manganese_oxide &#039;&#039;&#039;Manganese&#039;&#039;&#039;] based natural colors&lt;br&gt;<br /> * Manganese Oxide II MnO forms green crystals or powder<br /> * Manganese Oxide II/III Mn&lt;sub&gt;3&lt;/sub&gt;O&lt;sub&gt;4&lt;/sub&gt; can be brownish black<br /> * Manganese Oxide III Mn&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt; brown or black crystals or powder &lt;br&gt;<br /> [https://en.wikipedia.org/wiki/Carbon &#039;&#039;&#039;Carbon&#039;&#039;&#039;] based natural color&lt;br&gt;<br /> * Charcoal Black - unfortunately can cause cancer in specific forms (soot, charred food).&lt;br&gt;<br /> <br /> We know about these because they have survived for tens of thousands of years in caves and sheltered areas. The gold standard for &#039;&#039;archival&#039;&#039;.<br /> Other colorants are less permanent, but still useful on a human time scale.&lt;br&gt;<br /> <br /> I&#039;m specifically going to call out tannins and berries here.</div> Dan Barlow