Actually the reflection density-equation of halftone product is not satisfactory. In this essay, the author has investigated the relation between the halftone product with various degrees of dot percentage acorrding to vision and the continuous gray-scale with measured density.
The results obtained are as follows:
(1) The reflection density of halftone product is higher than the density of each equation.
(2) The following equation is made as a formula that agrees with visual density.
D=Pv-n′log{(1-a)+k⋅a⋅10^-d/n′} Pv: visual density (a=0) k: factor of paper and ink

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連続調画像を網点画像に変換した場合の網点画像の周波数応答 (Describing MTF) を測定するために, フラウンホーファー回折計を用いた光学的なスペクトル解析法を応用した。コンタクト・スクリーンと真空密着したリスフイルム上にコントラストの小さい矩形波像を投影・現像し, 網点による矩形波像を得る。得られた像のフーリエ成分は入力矩形波像のフーリエ成分に網点変換したときの網点の周波数応答を乗じたものに等しいと仮定すると, 網点像のフーリエ成分をフラウンホーファー回折計を用いて測定することによって網点画像の周波数応答が求められる。フラウンホーファー回折計を用いる利点として (1) 網点画像のスペクトル成分である信号波, 搬送波, および側帯派などの分離が容易となり, エッジ走査法などに比較して測定精度が向上する, (2) 広い面積部分の平均値を測定できるので, 網点に対する信号の位置や方向が種々に変化した場合の平均の特性を求めることができるようになる, の二点があげられ, 網点画像の解析に適した測定法であると考えられる。

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Methyl Vinyl Ketone (MVK) is a colorless, irritating and reactive liquid.
Photo-polymerization of MVK was reported by H. W. Milville et al and Y. Tabata et al.
Now, we have investigated the photo-polymerization kinetics of MVK which carried out in liquid phase by the light of longer wavelength than 300n.m..
The photo-polymerizations with azobisisobutyronitrile (AIBN) and without initiator have been studied in various solvents such as ethyl acetate, dioxane and acetone.
This reaction was considered to proceed by free radical mechanism from the fact that the polymerization is retared by radical scavenger.
The overall rates of polymerzation (Rp) were expressed as follows:
Rp=k[MVK]^2.2 in dioxane Rp=k[MVK]^3.8 in acetone Rp=k[AIBN]^0.6[MVK]^1.6 in dioxane Rp=k[AIBN]^0.6[MVK]^2.2 in acetone
This results did not agree with usual first order reaction on monomer.
Also, the apparent activation energies were measured to be 3-6kcal/mole.
Good results were obtained on application of MVK to graphic arts for photo-polymerizable compositions.

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