Mach bands are illusory bright and dark bands seen where a luminance plateau meets a
ramp, as in half-shadows or penumbras. A tremendous amount of work has been devoted to …

Foveal perceptive fields (center plus surround) for human vision were investigated by means
of contrast illusions in grids and bars. The task consisted of determining the size of the …

The appearances of fields that contain luminance discontinuities (eg, the contour between a
bright and a dark region) do not conform satisfactorily to predictions from models of spatial …

PURPOSE A blurred target presented to one eye may be suppressed when a clear target is
presented to the other eye. We sought to determine how this interocular suppression varies …

The foveal increment threshold is known to be raised at the boundary between dark and
light fields, but there are large differences in the magnitude of the effect reported. In the …

The detection threshold for a target has been previously shown to be affected by the
physical sharpness of the target's edge. The present study confirmed that the detection …

Measurements on the influence of the geometrical proportions of the stimulus on the Bezold-
Briicke hue shift are reported. The hue shift is measured by a comparison of the colour of two …

The spatiotemporal visual response to an inducing bar of a short duration was studied by a
brightness-matching procedure. The apparent brightness of a test line, presented in the …

Increment threshold of a small test probe is found to be elevated by backgrounds of a disk,
bar, or luminance step. The spatial parameters that produce maximum masking are found to …

Increment thresholds were measured for a small, briefly presented test line as a function of
distance from a high-contrast abrupt luminance edge. The experiments were carried out …