Dainippon Screen Seizo Kabushiki-kaisha

Tsuneo Takagi

Koichi Isono

Hiroyuki Yonehara

Controlling the exposure time in the reciprocity law failure range of a photosensitive material, in a picture reproducing machine, wherein the response time variation cause by variations is corrected according to the operational equation for the reciprocity law when the photosensitive material is in its linear range, by exposing said photosensitive material for a time t.sub.m in accordance with the relationship; ##EQU1## wherein T.sub.0 is the correct exposure time in the absence of reciprocity law failure, M.sub.i is the desired reproduction scale and P is an empirically determined coefficient which is greater for enlargements than reductions.

Method for controlling an exposure time in consideration of the

A method and machine for automatic focusing in a projection system with continuously variable magnification, wherein an original picture is projected onto a photosensitive material by a focusing lens, wherein one of these three members is fixed and the other two members are moved in a direction of a light axis by moving means, wherein the positions of the two moving members are detected by detectors, and wherein control means controls that, when the magnification of a picture image is changed, one moving member having a larger moving rate than that of the other moving member is moved ahead of the other moving member and the other moving member is moved dependent on the one moving member so that the picture image projected may constantly be focused onto the photosensitive material.

Method and machine for automatic focusing in a projection system with

A method and apparatus for correcting the reciprocity law failure of a photosensitive material to be exposed, for use in a picture reproducing machine such as a process camera are disclosed. Luminous energies of an original picture and a standard picture are detected by a light detector, and then the exposure luminous energy is compared with the standard luminous energy by an arithmetic unit. Then, an exposure time is calculated in a calculator by using the comparison result and fundamental data such as the standard luminous energy, a standard exposure time predetermined, and a correction factor predetermined, which are recorded in data setup means.

Method and apparatus for correcting the reciprocity law failure of a

A color correction apparatus for a duplicate camera wherein three color correction filters of three primary colors are provided and are selectively interposed into the exposure light path, is disclosed. An arithmetic unit is connected to a color correction value setup means which sets up color correction values of colors to be removed from an original picture, and it receives these density values as negative values and subtracts the minimum value thereof from each of the other density values to outputs a color correction signal. Then, a control unit connected to the arithmetic unit controls the color correction filters so that they may be interposed into the exposure light path according to the color correction signal.

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Kurita, Japan

Tsuneo Takagi