After you're finished your blend, make a copy and paste it somewhere, and on that one, go to Colours > Decrease Colour Depth > 2 Colours (1 bit)
Palette Component - Grey Values
Reduction Method - Ordered Dither
Palette Weight - Weighted
Then take that one and paste it on your original blend as a new layer, then on the layer palette set it to soft light, overlay or whatever you think looks good
