Sunday, October 6, 2013

Common Pigments in Tube Oil Colors

Part of my paint stash

In my plein air painting workshops, both all-level and advanced, the question of "hues" comes up.  A student will show up with a tube of cerulean blue hue or the like and will wonder how it compares to real cerulean blue.  The common thinking is that a hue, because it isn't the real thing, is inferior.  We all know, for instance, that margarine doesn't taste anywhere near as good as real butter.

Well, that's not necessarily the case with oil paint.  Hues were created because either the pigment became too expensive to mine (manganese blue), too scarce to find (indian yellow, which also had animal cruelty issues*), or extremely toxic (lead or flake white.)  Today, we have manganese blue hue; a replacement indian yellow which is called, simply, indian yellow; and replacement flake white.  In the case of manganese blue hue, Robert Gamblin of Gamblin Colors tells me that he feels the hue is actually superior to the real manganese blue hue.

Hues should not be confused with "student grade" paints, which are without doubt inferior.

Another question that comes up is, What is that odd-named paint made of?  King's Blue, for example.  King's Blue is, in many cases, simply ultramarine blue and white with perhaps a touch of phthalo blue.  Most manufacturers list the pigments on the back of the tube (and certainly on the website).

In all of these cases, I find it handy to have memorized the pigment color index (CI) numbers of my basic palette.  It saves me the trouble of having to go to a reference book when I want to see what's in a paint.  Here are my colors and their components (all Gamblin).  You'll note I use a couple of hues:

  • Cadmium yellow light - PY35
  • Cadmium yellow deep - PY37
  • Cadmium red light - PR108
  • Permanent alizarin crimson – PR177 + PG36 (real alizarin crimson is PR83 and fugitive)
  • Ultramarine Blue - PB29
  • Cerulean blue hue – PW4 + PB15 (real cerulean blue is PB35 and expensive)
  • Phthalo green - PG7
  • Burnt Umber - PBr7
  • Titanium-Zinc White – PW6 + PW4

* Real indian yellow was created by feeding cows a diet of nothing but mango leaves, and the resulting urine was processed into the pigment.

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