Colour selection of high-redshift sources. Top panel: IYJ diagram for z ~ 7 candidates (cyan points: sources with 1σ detection in B₄₃₅ or V₆₀₆, which we exclude from the selection; green dots: H-detected sources, undetected in B₄₃₅ and V₆₀₆; blue stars: IR-detected sources, undetected in B₄₃₅ and V₆₀₆; red dots: H-detected z ~ 7 candidates; magenta stars: IR-detected z ~ 7 candidates; empty black circles: Atek et al. (2015)z ~ 7 candidates; arrows represent upper limits). Bottom panel: YJH diagram for z ~ 8 candidates (symbols have the same meaning as in the top panel, except that the cyan points represent sources that we exclude from the selection because they are detected in B₄₃₅, in V₆₀₆, or in I₈₁₄).