Seconding the gouache idea for speed.  I use watercolor pencils with 
watercolor rather than traditional colored pencils.  That's an option.  What 
kind of substrate were you planning to use?  As for the fading, do you need 
it to be long-lasting?  I don't look for longevity because 1) I have a high 
rez scan made & 2) sell the giclees, not the original piece.

As an aside, my clients generally balk at any colored background in the 
final digital image.  Because it takes so long to professionally "cut out" 
the colored background to make a white background, I've stopped using a dark 
ground to save time.  I might use it for other effects but definitely not 
for the time savings.

Gina
http://www.scientificillustrator.com/


----- Original Message ----- 
From: "Maia Sanders" <[log in to unmask]>
> I am looking for a relatively painless way to render a light subject
> on a dark ground, and still be able to reproduce it.  I am trying to
> see if watercolor is a good medium for this, but it is looking like a
> combination of WC and CP is going to be better...
> I think a dark ground will be difficult to work on as they seem
> smoother and harder, somehow, than my preferred substrate, strathmore
> 500 plate.  I also worry about substrate fading.   I could do a
> different substrate if I needed, but I prefer to do some
> layering/burnishing with the CP. 

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