@farmerman,
Actually van Gogh was NOT an impressionist. He nd Cezanne, Seurat, Sisely, Toulouse La Trec, Gauginetc rejected the whole concept that color alone would describe their efforts (the basis of impressionist painting). The post Impressionists (as they were later called) futzed around with many things like line, little dots , mosaic structure etc. Most of these guys didnt know that they would be grouped as post Impressionists caue the term wasnt invented until about 1910 and most of these guys were dead by then. (I believe)