White synthetic brushes are the go-to tool in many artists brush vases. A core brush for acrylic painters especially. A great general duty brush, series 6100 have a soft flexibility that is perfect for low to medium viscosity paint. For heavier bodied acrylics and oil paint we recommend 6200, and 6300 series, both with firmer tufts. White synthetic will still be very effective for blending and smoothing these heavier mediums. Long Handle – A medium-stiff brush that performs well with low to medium viscosity paint. Brush sizes – The length and width of brushes given shape and size may vary by brand as brush sizes are not standardized. Most fine art brushes are handmade and as such some variation is expected even among brushes from within a single brush line.