Illuminated N - Counterspace and Start of Shading

I've done the counterspace (so's to speak - the counterspace within the vines) in black goauche. It looks positively velvety.

I started doing the shading on the gold yesterday using black.
The flower and vine I've done do look 3D but they also look murky. I'm loosing a lot of the brilliance of the gold.
I did a quick consult to check that Nick was happy with the type of shading, as opposed to perhaps going for a goldvine style letter - for example


which has outlining and some detailing in red - but not actual shading on top of the gold.

Nick likes the black shading, so I need to address the murkiness problem.

I spray fixed the right side of the painting last night and will see how that takes the black.

I'll take the already shaded parts back down to paper and re-do them. I really do want as much bright gold as possible.

Thanks to Elyse Boucher for her paper on Whitevine and Goldvine, from where I learnt the existance of goldvine letters and readily directed me to one of my books for an example
http://www.geocities.com/CollegePark/Library/2036/whitevin.htm