In this study , We made so皿e experiments し o ・ elarify the influence of observation distance and background on the apPearance for stains on external builcling wal 工 , The results may be sum 皿aPized as follows : ( 1 ) For the same stains of wall surfaee, dis しant view with background and close view differ remarkably from each other in discomfort of 〔 iegree 幽 and intermediate view with background and close view also differ from each other in disco 皿fort of degPee close view aceDrding to kind of

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... inishing materials , ( 2 )Aease Df seeing at c ユ ose . range and a case of seeing at a distance differ fro 皿 each other in disco 血fort of de8ree fDr stains , Keyvords : numeration of stains , discomfort , observation distance , baokground , method of 皿agnitude estimation