Mixing a neutral 'black' glaze - quick tip

I recently discovered the use of an ND (neutral density) filter as reference when mixing a neutral transparent glaze.

I needed to make some minor adjustments in some shadow areas without affecting the hue, and found no pigment that was both neutral in colour as well as transparent enough for subtle glazing. Then I saw my ND Filter on my desk, which gave me an idea. ND Filters are made to reduce light in photography without affecting colour and are completely grey to almost black in appearance. Mine are pretty dark, because I use them for long exposure during day time. A somewhat lighter one would be better for this purpose. Seeing that a glaze works pretty much in the same way than most optical filters, the ND filter served as an excellent reference to mix a neutral transparent glaze. The pigments that worked the best were Ultramarine and Vandyke Brown. I tried Burnt Umber; that however shifted towards green and never really became neutral.

This mixture is only neutral when used as a glaze and will shift towards blue when mixed with white, unless yellow is added, in which case Burnt umber would be the better choice.


Stellar idea Peter!!! Thank you so much for sharing. I will definitely try this. :smiley:

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Hmm… interesting. Perhaps one could construct a shading series with such a tool.