Watercolor, the most immediate of all painting mediums, is just pigment and gum arabic soluble in water. To use it, all you need is a jar of water, a sable hair brush and some good hot-pressed paper or Japanese sumi on which to work. Oh yes, and a feel for original composition and a lifetime of skilled experience. Watercolor cannot be corrected; mess with it and you are lost. Few, if any, Israeli artists are better at conveying the medium's transparent watery riches than Pamela Silver (b. South Africa, 1948, here since 1973) whose work currently fills three rooms at the Jerusalem Artists House. Silver began as an instinctive painter but her work has become increasing sophisticated over the last decade. Her latest show of many parts contains a few dazzling innovations, particularly the Eye series, in which a few calligraphic stokes of a large brush are placed in relation to one another with the eye of a Japanese calligrapher. These are also rendered in deep, nearly opaque color, lending them a special power. While Silver has learned here that less is more, she shows other successful works that contain a myriad of little experiences and areas of wash, expertly brought off with a variety of brush points. Just look at the three large loosely circular paintings in the foyer. One is a watery spiral, its neighbor a group of washes seen against tiny drawn additions, a case of instinctive beginnings gradually combined into a meaningful whole. Neither is overworked.