Sure, it wasn’t anything fancy and I cheated a little
Line work was uploaded into my editing program. I do color work in Paint.Net rather than GiMP which is more popular but same concept (free, layers, limited filter functions, etc.). Added 2 layers above the linework layer, one for each blocked shade (there was a light grey and a dark grey for the shield/helmet and deep shadows in the folds and so on) and set the layers to ‘Multiply’ so I could still see the linework below for painting and then cleaning up where I colored outside the lines.
Last layer went below the everything else and was a radial gradient from black to white centered on, well, the center. I then used the linework layer as a guide to clean out any space that it would’t be seen. This also could have been done by filling the line layer with white in those spots, but it was a coin flip as to which was more work so I usually err on not touching my lines layer.
Exported to .png, imported to my .svg in inkscape on a second layer, made sure everything lined up good and uploaded to the GF to do the voodoo it do.
Here is where I cheated: Nothing says I have to accept the shading the way it was burned in. A little sandpaper can go a long way to remove color on a burn for a wood as light as this. I usually hit my engraves with a quick pass of the sander at 220 grit just so take off scorch marks where i was to lazy to mask, but it worked awesome to play around the edges with and really feather that gradient out