Hardness ratio as a function of the normalised count rates for the variable AGNs described above. 1H 0707–495 data are shown as light blue open stars, CGCG 229–015 as black open squares, NGC 4395 as blue open circles, Mkn 335 as green open triangles, and IC 3599 as filled red circles. Count rates are normalised to the minimum rate observed. The hardness ratio is computed as the ratio as (H − S)/(H + S),whereH is the number of counts in the 2–10 keV energy band and S the number of counts in the 0.5–2 keV band.