there are many small kaolin deposits in iran , which are extracted and used in ceramic industry without any treatment. this investigation was aimed to study the ore and to find whether a fine material can be produced for paper usages. the ore was studied by xrd, dta, optical and scanning microscopy. physical properties, such as brightness were also examined. the main minerals , presented in sem...

Abrupt changes in luminance trigger and restrict brightness filling-in. If brightness was actively filled-in and mediated by cells signaling both luminance borders and surface brightness, then brightness spreading could also get disrupted by changes in texture. We measured psychophysically the brightness of a uniform luminance disk, which was segmented into two parts by different textures. The ...

Recent physiological studies show that neural responses correlated with the perception of brightness are found in cortical area V1 but not earlier in the visual pathway (Kayama et al., 1979; Reid and Shapley, 1989; Squatrito et al., 1990; Komatsu et al., 1996; Rossi et al., 1996; MacEvoy et al., 1998; Rossi and Paradiso, 1999; Hung et al., 2001; Kinoshita and Komatsu, 2001; MacEvoy and Paradiso...

Changes of annulus luminance in traditional disk-and-annulus patterns can be perceived to be either reflectance or illuminance changes. In the present experiments, we examined the effect of varying annulus reflectance. In Experiment 1, we placed test and standard patch-and-surround patterns in identical Mondrian patchworks. Only the luminance of the test surround changed from trial to trial, ap...

revolution the distinction between energy and information was less clear, and the term brightness was used to refer to both lightness and brightness, without distinction. Sometimes the term brightness is used for the perceived brightness of the illumination level. But perceived illumination and perceived luminance are separate, and by consensus, the term brightness is now used to refer only to ...