Been going 14 hours straight on this de-lined cape inside blackening. Let me tell you honestly, I tried dye, paint, leather dye, fabric marker, sharpie, spray paint etc. nothing gonna not wash/rub off. This thing looks/ behaves like suede but its some kind of synthetic creation. Nothing is doing the trick.
But I got it looking great with a few light washes of acrylic paint and a fabric marker over lay then hours and hours of rubbing to break down the fibers to get it to be as flexible as before I coloured it as well as remove excess color so it won't rub off as easy. You could rub for months and eventually it would all come off, nothing's staying on this thing permanately not even straight acrylic paint.
I sprayed the thing with leather protector as well hoping it will act as a sealant but it still rubs off. To the light touch though, it's fine. The suit is black plus I have another body so I could pose this one without worry. Ill get another belt too just in case this one stains. The way I look at it is it should be fine even if its not permanately tinted and I don't think it will stain my fingers when I play with it or anything.
I'm hoping this will know look like the batman I always wanted it to and be deserving of the praise its getting,
For those de-lining. You'll have to make a choice weather you want to color it and risk the color coming off onto the figure or to live with it being gray.