Brightness functions were determined for the dark-adapted fovea and periphery. In one series of experiments, observers matched numbers to the brightness of a 1° white target at various intensities, presented half the time to the fovea, the other half to one of five peripheral loci: 5°, 12°, 20°, 35°, and (;0°. In a second series, observers matched the brightness of a 1°white target in the fovea...

The relationships between lightness and brightness responses under the condition that achromatic "surface color " appears and the relationships between perceived illumination and brightness were examined. The Ss were required to make categorical judgments upon both lightness and brightness of the test patches presented on black and white backgrounds and upon the over-all illumination in the vis...

We investigate anisotropy in 1.4-GHz brightness induced by a field corn vegetation canopy. We find that both polarizations of brightness are isotropic in azimuth during most of the growing season. When the canopy is senescent, the brightness is a strong function of row direction. On the other hand, the 1.4-GHz brightness is anisotropic in elevation: an isotropic zero-order radiative transfer mo...

A series of experiments was performed to evaluate the effect of substituting sodium carbonate for the sodium hydroxide used in peroxide bleaching of spruce CTMP. Three peroxide levels were tested: I , 2, and 4% HzOz, and two levels of causticsubstitution; SO% and 80%. At both the 2% and 4% peroxide levels, substituting 50% of the caustic charge with sodium carbonate decreased the initial bright...

We present measurements of focal spot size and brightness in a focused ion beam system utilizing a laser-cooled atomic beam source of Cs ions. Spot sizes as small as (2.1 ± 0.2) nm (one standard deviation) and reduced brightness values as high as (2.4 ± 0.1) × 107 A m-2 Sr-1 eV-1 are observed with a 10 keV beam. This measured brightness is over 24 times higher than the highest brightness observ...

Most vision scientists are comfortable with the idea that perception is a multi-level process. For example we take it for granted that the two best understood properties of human colour vision, trichromacy and colour-opponency, are underpinned by physiological mechanisms operating at different stages in the visual pathway. The observation that any colour can be matched by a suitable mixture of ...

which had Galileo among its members. He commissioned artists to record plants, birds and animals for his museum and a pictorial encyclopaedia that attempted to understand and classify both the natural and ‘man-made’ world. Alexander Marshal’s floral paintings were compiled at a time when the cultivation of gardens had become a pursuit of scholars and collectors, keenly interested in exotic spec...

Rod modulation of an annular surround can produce brightness contrast in a test field centered at 100 from the fovea. In our research, stimuli originated from a colorimeter that provided 4 primaries in both the circular test and the annular surround fields, and allowed independent modulation of the rods and each of the short (S)-, middle (M)-, and long (L)-wavelength-sensitive cone types. The c...

The production of unprecedentedly high brightness electron beams is a critical aspect of many applications, from free-electron lasers to advanced accelerators. The preferred method for obtaining these beams is the radiofrequency photoinjector. The physics and technology aspects of this device are reviewed here, along prospects for future progress in high-brightness beam development.