This is nothing special and I have mentioned it in another thread but I thought I would put it here because it's very handy to know, although I'm sure others do this too, I've never seen it mentioned. Anyway, I had so much fun doing the hair on my Jessica painting and the success of that has moved me to share how that was possible. I used the Zwaan-Morton No, 10 blade, that's this one; Whilst I'm sure everyone has and uses these, it's not so much the blade that is important as what I did with it, firstly I used old blades that literally did nothing more, but, I dragged the tip of the blade along a piece of 600 wet & dry (dry of course) sand paper, I do this with the blade leaning flat at roughly a 30 degree angle and dragging always in one direction, what's important here is if you do that the blade works only in one direction, so I did two blades one dragged to the left and one dragged to the right, this mean I can scrape in the backhand as well as forehand. Doing this allows your blade to slice easily through the paint, even if the paint is days old, because there is so little pressure required for it to do what it does, there is less chance of it damaging the paper, how it works is that after dragging it the other side of it acquires tiny microscopic hooks which can't be seen with the naked eye, but it's these hooks that do the cutting. Using this system will allow you to achieve super fine lines without having to change to another blade type, all the fine fly away hairs on my Jessica painting are done with this with unbelievable ease. Give it a try and let me know how you get on, and remember because this works on old blades as well as new, you'll be forking out for new blades a lot less frequently.