My painting style is very detailed and a lot of my work has very small objects with lots of detailing. I also fine line pen on many parts of the painting and at present I also simply use a fine liner brush and cut back in with other colours until I am happy with the finish. I have often thought it would be much easier to use a pen that I can fill with acrylic paint to use just like a fine line marker. Does anyone know if such a thing exists? I know nail artists use pens but I'm not sure if these will be suitable.