用数学模型解算感光材料的特性数值
The Calculation of Characteristic Values of Photographic Materials by Using a Mathematical Model
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摘要: 在感光测定中,一般都用图解的方法从感光特性曲线上求出感光度、反差系数等特性数值。由于图解的方法精度低,因此,测定的数值很不一致。本文介绍日本犬井正男,柏修司所提出的利用一个数学模型进行数字解算感光特性数值的方法,分析了根据该数学模型计算感光度和反差系数的公式,并推导出平差计算的步骤。在TQ-16电子计算机上计算了10条特性曲线,与图解平均值(5人)进行了比较,其感光度差值在±0.6以内,反差系数差值在±0.06以内,所得结果与犬井正男,柏修司的试验结果一致,因此,可以认为该数学模型是合理可用的。Abstract: In sensitometry,the characteristic values of sensitivity and contrast coefficient are generally,obtained from photographic characteristic curve graphically.Because of the low graphical accuracy,the determined values are quite inconsistent.Masao Inui and Syuji Kashiwa(Japan) have suggested a mathematical model which may be used to calculate numerically the photographic characteristic values.In this paper,the equations to calculate the sensitivity and contrast coefficient by the model are analysed and the procedure of calculation by adjustment is derived.Ten characteristic curves were calculated in the TQ-16 electronic computer and the obtained values were compared with the graphical ones(five persons).It was found that the discrepancies of sensitivity and contrast coefficient were within ±0.6 and ±0.06 respectively.The result was consistent with the experiment carried out by Masao Inui and Syuji Kashiwa.The adopted mathematical model is proved to be very practicable.
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