So I had my 3 calico girls all sewn up and painted with gesso in all the areas that I want to paint with acrylics, or sculpt with paper clay: the faces (leaving the scalp un-gessoed to sew on the hair) the hands and the boots. Without gesso the paper clay will just fall right off your doll, it cannot adhere to the cloth. Some people use PVA glue as a bonding layer but I prefer Gesso as it takes paint better in areas that get left exposed. I only paint to just above the ankles on the boots as I make the upper parts from leather with a tongue, so I just paint the lower part of the foot to match. Simples! Here they are drying out after they have been finished, I tend to cover the paper clay with another coat of gesso, when the doll is all white it's easier to see if you need to fill any craters or adjust features you don't like...
Somebody dust that mirror and don't even get me started on that ghastly light fitting! You will have to forgive the truly awful photos but I can barely walk at all plus it's still very cold so don't tend to venture far from the fire and it's also very dark most of the time. The second pic shows where I apply the paper clay to my dolls faces. I am basically smoothing out the fabric puckering on the jawline and creating a chin. With these dolls, I will leave the face completely flat, on the larger dolls I create shallow sculpted features. I usually make a dome for the eyes, let that dry then sand the surface to make it nice and smooth. The eyes are just little bulges on the surface and then I add eyelids on top of the dried eye bulge. It gives that buggy eye effect that I'm so fond of!
This pic shows 2 dolls drying out by the fire. I use the paper clay (called papydur, a powder you mix with water which sets absolutely stone-like) very dry, mixing in hardly any water, but it still takes ages to dry. I just apply it to the gessoed areas with a small craft tool and then smooth it into the shape I want with a wet finger. My first attempts were to use a wetter mix and I got great results but as it dried out, the sculpted features would just evaporate with the moisture, sinking into the gesso somehow. There is a lot of shrinkage, so now, the drier the better. I have also found by trial and error that with Papydur, you need to smooth out the surface as much as possible before leaving it to dry, as once it's set it is difficult/impossible to sand. The reason I am using Papydur as opposed to LaDoll or one of the finer ready mixed Paperclays that sculpts well over an armature, is the simple fact that I am working over a 'soft sculpt', it needs to be rigid in certain areas if you want to paint or sculpt on top or you will get cracking.
As well as the jaw/chin, I also fill in around where I have sewn the head onto the neck. If you decide to do this you need to apply the clay quite heavily or it will just crack and detatch itself from the neck the first few time the head moves. I like the head and neck to look all one even though I create them separately. Lastly, I model a flat platform under the boots and heels and fill it in, smoothing it up to the stuffed calico foot. This will need sanding later but try to create a smooth level surface and then your doll may be able to stand unaided if you are using tight button knee joints. It's quite cool when they do that!