I made slow progress with my de-saturated Sisters.
First I highlighted the reds.
Then a coat of Baal Red wash to smoothen the transitions and some work on the dark greys.
I worked a bit on the faces (almost invisible in all the greys) and highlighted the "white" - speak the greys :)
For this I'm grinding Pastels and mix the powders as I need them.
First I apply the powders with a dry brush,
and then I use spirit to fixate the pigments.
You must be very careful when applying the spirit, so it doesn't strip any of the colors.
Once everything was dried I placed the Sisters on the base.
Here you can see that the pigments work really well.