Influence of area effect in color appearance at the pictorial image observation.

“面积，色彩效应”是指一个色场的色彩外观的饱和度和明度随着色场面积的增大而增加的现象。本研究项目的目的是了解这种区域效应的特点，探讨颜色区域效应的影响因素。我们在这项研究中所做的第一步是“量化颜色的区域效应”。我们展示了一种颜色的一对色场作为视觉刺激，它们的色度相等，但面积大小不同。观察者调整一个小的匹配刺激的颜色，使匹配刺激的颜色外观与一个大的测试刺激相同。通过对测试刺激各区域大小的匹配，计算了亮度和饱和度方向上区域效应的大小。结果表明，亮度和饱和度随面积效应的增加而增加。但我们观察到区域效应对色相的依赖性，红绿方向的区域效应强于蓝色方向。第二步，我们进行了“色彩面积效应的空间特征考察”，明确了面积效应的影响因素。在这个实验中，我们用暗线将大的测试场划分为小的彩色芯片。我们做了同样的实验，只是用了这个刺激。结果表明，面积效应随着测试刺激的分割而减小。在大的测试刺激中观察到的面积效应的色相依赖性也被保留，并且在所有条件下亮度和饱和度增量的下降近似成正比。这意味着被中央凹捕获的小色块不足以保持区域效果。今后需要进行新的实验，将非线性空间和效应纳入面积效应的建模中。

"Area, effect of color" is the phenomenon that saturation and lightness of color appearance of a chromatic field will increase, as the area of the field becomes larger. The purpose of this research project is to understand characteristics of this area effect and investigate factors of the area effect of color.The first step we did in this research was "Quantification of Area Effect of Color." We exhibited a pair of chromatic fields in a single color as visual stimuli, those were equal colorimetrically, but area size was different. The observer adjusted a color of a small matching stimulus so that the color appearance of the matching stimulus became the same as a large test stimulus. As the result of matching task in each area size of test stimuli, we calculated the magnitude of area effect in lightness and saturation directions. In the result, increment of the lightness and saturation as the area effect was observed as expected. But we observed the dependency for hue in the area effect, and the area effect of red-green direction was stronger than blue direction.As the second step, we performed "examination of spatial characteristic of the area effect of color" to clarify factors of area effect. In this experiment, we divided the large test field to small color chips by dark lines. We performed the same experiment except using this stimulus. As the result, we found that the area effect decreased with the divided test stimulus. The hue dependency in the area effect observed in large test stimulus was also preserved, and the decline of the lightness and saturation increments was approximately proportional in all condition. It means that small color patches caught by fovea are insufficient to hold the area effect.It is required to perform the new experiment that will incorporate nonlinear space summation effect in modeling of the area effect in future.