SU86823A1 - The method of calculating the determination of correction light filters when printing color films - Google Patents

Description

Selection of corrective light filters when installing light for printing color films is currently being done by test printing, which requires a lot of time, film, chemicals, and masking equipment.

The described method for calculating the determination of correction light filters when printing color films does not have the indicated disadvantages.

According to the invention, the plot part of the object being shot {human face, greenery, sky) or the achromatic table and generally any place obtained on the color positive is measured on a conventional densitometer or a photoelectric densitometer with three-color light filters.

Denote the density in the blue, green and red zones measured

positive colors without correction via DC, D and DK. If the zonal densities of a given color are known, then by designating them by D, D., and D, it is possible to calculate the zonal densities of the corrective optical filters.

: Denoting further the zonal densities of the correction filter through DC, Dj and DK, we obtain

Since the color rendition on a three-layer positive film is not ideal, but optimal, for a better selection of corrective light filters it is recommended to measure the positive images of a number of plot-relevant objects of the survey; the human face, the greenery, the sky, the achromatic table, and a number of other colors encountered when shooting, and express them through

An approximate calculation of the corrective light filters for the object to be removed is trivialized below, the achromatic color of which and the zonal raft D -.: D - D, - D D,

 - D ,,.

D ,, D ,, and D ,.

No. 86823; - - 2 bounds on the positive when printing from a negative without corrective light filters are as follows:

- D 0.96 D 0.96 D 0.42.

These characteristics show that this positive is red, and for achromatic color, condition D - should be met.

 D, - D ,,. Suppose you need to get an achromatic color, v of which:

D, 1.2 D, 1.2 D, 1.2

In accordance with the above formula, the zonal densities of the corrective optical filters will be as follows:

D; 0.96-1, 24 D; 0.96-1, 24 D; 0.42-1, 78

In order to turn each negative value into a positive one, we add in each zone Ox:; well, the same density is 0.78, which is equivalent to adding an achromatic color.

In this case:

These characteristics indicate that a corrective light filter is red, and only when printing a positive with such a light filter, you can get a positive achromatic color from which D ,. D-, D. 1.2.

Sets of corrective light filters: yellow, magenta, and cyan, used in production to install light when printing color films, must be expressed in zonal densities.

Subject matter

The method of calculating the determination of correction light filters when printing color films, characterized in that, in order to find their zonal densities, a negative film of a gray or color field of a certain color is printed on a positive film without the use of correction filters, and then they are subtracted from their zonal densities. specified or known zonal densities.

D 0,54 0,54 D: 0,00