Leaving colors behind

A parallel that I've recently pondered between a living leaf and one drawn in pastel is that both are enjoyed in virtue of the colored pigments present in the surfaces.  Fall leaves, like oak, lose their Chlorophyll as fall progresses, leaving other pigments visible that were overpowered and masked by the green photosynthetic molecule. Carotenoids (accounting for yellow, orange and brown) and Anthocyanins (responsible for reds and purples) remain after the Chlorophyll's green diminishes.  So a leaf's autumnal allure results from a subtractive process that removes and degrades certain molecules, presenting a visual experience that subtly changes as the days pass.  

Autumn has a progressive quality that unveils waves of color; revelations of reds, yields of yellows, occasions of orange and presentations of purples.  Autumn leaves loose their green utility and fail to "sing" with one green accord.  The many species of trees re-emerge, visually, no longer verdant voices, singing in unison.  We are increasingly aware of the new song being sung by the poly-chrome chorus.  The conductor that is nature cues a decrescendo of green, while the other colors, there all along, are given full voice for the climax of the fall performance.   

So the natural process of leaf color change relies on subtraction, whereas drawing often relies on the addition of color to produce the effect.  Producing a pastel leaf entails the application of colors to an abrasive surface (pastel card in this case).  This process is preservative because it is additive, each mark a record of a memory.  The final effect results from a visual and physical blending of colored areas.  

Two ways then, leaves are seen singing.  The drawing serves as a record of the performance, mediated by memory.