A tray for a panel exposure machine, and also such a machine, enabling a panel to be retained and pressed down so as to be presented facing an exposure device. The tray comprises a work surface (13) adapted to receive panels of different sizes, said work surface (13) being substantially plane and possessing first and second adjacent edges (13a, 13b) extending along substantially orthogonal first and second directions (X, Y) defining a reference corner (C); and first and second holder devices (30a, 30b) of a first type and at least a first holder device (40a) of a second type, each holder device being actuatable between a holding, first state in which it exerts pressure directed towards the work surface (13), thereby defining a holding position, and a rest, second state in which said pressure is released; a positioning device (14) arranged along at least a portion of the first edge (13a) and along at least a portion of the second edge (13b); the holder devices (30a, 30b) of the first type extend along at least a portion of the first and second edges (13a, 13b) respectively, their holding positions being fixed in a plane parallel to the work surface; the holder device (40a) of the second type is movable in a plane parallel to the work surface (13) in order to adapt its holding position as a function of the size of the panel in use.