density = np.load(densityCache)['density']
with open(PHOTROOT, 'rb') as f:
    HUGSPhotometry = pkl.load(f)[1]
color = HUGSPhotometry["F275W"] - HUGSPhotometry["F814W"]
mag = HUGSPhotometry["F814W"]
HUGSPhotometry['density'] = normalize_density_magBin(color, mag, density, binSize=0.3)