Comparison of the change in multiplicative bias and additive bias when some of the charge is trailed during the readout process. The amount of trailing is determined by the value of f_trail. The light coloured points show the (small) detection biases, whereas the bright coloured points show the −Δc₁ (black), Δμ₁ (blue) and Δμ₂ (red). The amplitude of the additive bias is about half of the multiplicative bias, but has the opposite sign, as predicted.