Continuing a discussion by Kuehni, this note examines the problem of fitting as many as possible colors in a 1-JND radius sphere such that each pair of colors is separated by at least _1 JND. Kuehni announced nine. A first estimate yields a maximum of 13, but this is too many because colors populating adjacent spheres will be too close to each other. Accordingly, I derive the maximum number,root 2, of discriminable colors per unit volume of color space, and then formally compute from this number packing density a number of colors inside the unit sphere. That estimate, nearly 6, will undoubtedly erode when discrete color points are chosen within the unit sphere..Kuehni's estimate of 9 is too high. (C) 2016 Wiley Periodicals, Inc. Col Res Appl, 41, 492,.512, 2016; Published Online 22 June 2016 in Wiley Online Library (wileyonlinelibrary.com).