stone filter idea was connected to two previously unpublished blocky filter packs, that I revisited now.
By compositing two turbulence filter primitives you can generate various patterns -like fabrics-.
These packs are based on the same concept, however I found the rest still a matter for experimenting.
The first pack had built in flood fills to start off, the second one is plain black with smooth alpha and the recent one is using new (in inkscape 0.92) blending modes.
Still I feel the shading lacking, as before.
By simply adjusting the rgb levels, one can get lighter colours but decreased saturation on a darker source. Same applies shading a light source by adjusting the rgb channels.
Overlaying blend mode may be the closest although I'm not satisfied with its results.
Ultimate solution is using different sources for the lighter and darker shades, however that can lead to way complex filters.
svg source 1
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