In short, the colors are very similar, but the finish and feel are different. The 1723 series features a silky smooth satin finish with a slight sheen. The 1961 has a more matte and textured finish. See the pictures below. For better quality images, right-click on the picture and select “open image in new tab.” If you’re on mobile, long-press on the pictures and select “open image in new tab.”
