Dependence of the Fisher_UGRIZW1 and Fisher_GRIW1 selections on z_spec and for our observed eboss6-7 plates. The dot size scales with the number of objects entering the bin. For each redshift bin (using z_phot), we colour-coded at log₁₀( the ratio of the number of selected photometric objects to the number of photometric objects passing all the cuts in Table 2 except the cut on the Fisher discriminant. The horizontal dashed line represents the approximate of objects with S/N = 3.