Star cluster aperture photometry errors and uncertainties of CIs F336W − F475W and F475W − F814W versus aperture radii. Top panels show the median of errors arising due to aperture positioning and size biases (σ_APT); middle panels – the median of scatter due to projection effects (σ_ROT); bottom panels – the median of scatter due to the stochastic IMF sampling and the spatial distribution of cluster stars, σ_GEN. Results for clusters with radial profile parameters, r_c = 0.2 arcsec and γ = 2.8, and 4 different cluster age and mass combinations (see legend) are shown.