* Bill Jacklin
* Hiroshi Sugomoto
* Josef Albers
* David Teniers the Younger
None of them are black.
Edit: As eyko pointed out below, these are not in the 'n' category. So I searched for people in that category, and all the ones I checked turned out to have been black (other than Mati Klarwein).
Howardena Pindell,0.7686921,n Mati Klarwein,0.7066092,n Barkley L. Hendricks,0.69986427,n Carrie Mae Weems,0.6645416,n Barkley Hendricks,0.6883637,n Yinka Shonibare,0.68256056,n Zanele Muholi,0.58554715,n Kehinde Wiley,0.66218376,n RETNA (Marquis Lewis),0.47963,n Wangechi Mutu,0.6394607,n Kadir Nelson,0.5669006,n Amadou Opa Bathily,0.5536976,n Juliana Huxtable,0.5364195,n Chinwe Chukwuogo-Roy,0.49445248,n Teophilus Tetteh,0.46064255,n Bruce Onobrakpeya,0.42588046,n