Next Wednesday we will talk about putting details into our silk paintings.
When using gutta it is hard to get fine details, yes you can get and area and fill it in with color, but something with a fine line or a small detail becomes more of a problem with the gutta and the applicator tip, no matter how fine.
These are Pigma brushes. They also come in pens with a variety of fine tips. They become permanent on fabric after they have been heat set with an iron. I have used them on both cotton and silk with very good results.