SU1190348A1 - Method of additional measured exposure of colour negative photographic materials - Google Patents

Description

The invention relates to the field of professional cinematography, in particular to sensitometry and photographic methods and processes, and can be used for pre-processing of film photographs immediately before the main exposition in order to take into account the optical and spectral characteristics and light scattering in film optics and movie camera that expands the information and visual capabilities of cinema and photo materials, increases the completeness and accuracy of the decryption, image rendering.

The aim of the invention is the expansion of informational and visual capabilities of film photographs by taking into account the optical and 20

spectral characteristics of the used filming equipment.

Figure 1 and 2 shows the characteristic curves of ϋ = G (1 ₆ .n). . 25

. Conducting additional dosage illumination on the proposed method is as follows.

First spend sensitometriches- ³⁰ Kie tests selected for the particular motion picture color negative film, which subsequently will be processed by additional metered exposure. For 35 of this:

1. Choose the type and axis number of the color negative film (for example, a film of the type DS-5M, axis 31817).

2. A piece of DS-5M film is charged with a sensitometer, such as the CS-2M, and a densitogram is printed on it.

3. An exposed piece of film with a sensitogram is shown

in the developing machine in standard tech- ³ technologically mode.

4. Then, densitometric measurements of the optical densities of the densitogram fields behind the optical filters are made on a standard densitometer-50 meter, for example, MACBET-TD504. Based on the obtained densitometric data, three characteristic curves are constructed for the yellow, magenta, and blue layers of color negative film.

5. Based on the obtained densitometric data, calculate

sensitometric characteristics

selected film. (Received

sensitometric characteristics

and the curves are called primary).

6. Determine the parameters of the additional dosage of light, taking into account the light scattering in the film. the camera and in film optics, for which the following operations, measurements and calculations are performed:

a) as a physical model of an absolutely black body, they use a box glued inside with black

 velvet, on one of the sides of the box there is a hole; The box has a hole in front of the white screen to the lens of the movie camera;

b) select the type of film camera and film lens, which will produce the film, and carry out their tests;

c) filming with metered exposures of a black body on the white field of the screen - with a given color temperature

and the directivity pattern for the color negative film selected by π.1;

g) carry out chemical-photographic processing of the exposed film in p., make a densitometric control of the developed film according to claim 4, based on the obtained densitometric data build three characteristic curves according to claim 5, calculate the sensitometric characteristics from the results of den-.

'simetric measurements.

¹ 7. Calculate the layered imbalance

film layers introduced by film optics and light scattering in film optics and in the camera, in contrast and in sensitivity to light. These input operations are designed to certify the used film optics and the camera of additional dosed illumination according to color and gradation characteristics.

The imbalance and the parameters of the additional dosage illumination are calculated as follows,

Choose a reference gradient of 8 _{σ [} , ₀ ρ _Η ·

Additional dosage method

the flares balance the film

matching gradients between dot3

1190348 4

Kami 1β Н _{о <} , corresponding to the density level 0 = 0.1 over the veil of the primary characteristic curves of the layers of the selected film axis and a point (1β H _{0 | (} + A). The value of the coefficient A is chosen equal to 1.1 of the process conditions. This is the interval 1d N exposures, on which the difference between the optical densities of the characteristic curves of the film in the last metered additional illumination, and the primary one, obviously exceeds the error of densitometric measurements. the stiff curves of the layers, so among the gradients of the characteristic curves of the layers obtained with regard to the action of light scattering in optics and in the camera, the minimum gradient is chosen as follows: on the captured motion picture of an absolutely black body, after chemical photographic processing and densitometric measurements, the values of optical densities above the veil and mask Pr where ΐ = 1,2,3, which characterize the action of light scattering in optics and in the movie camera.

Determined by the primary characteristic curve exposure levels, giving the value of optical density

ten

15

20

25

thirty

35

According to this gradient, the selected axis of the color negative film according to π.1 is balanced by the method of additional dosage illumination.

The parameters of the additional dosage illumination are determined as follows: from a point on the primary characteristic curve (FIG. 2) corresponding to the value (ΐ £ H ₀₎ +

+ 1,1) hold a straight line ΐβц £ = b _Ojori 'to the intersection with the vertical at point 1b _? H ₀₁ . The result is a point ϋ * _Οι, calculated characteristic curve of film (PG). subject-; newer extra dosage illumination balancing the selected film material

= αί_ίΐΛ! ΐ_Σ_Ρ ° .’_

®0PORN T, 1 ~

\ = g (1e n _{0> 1} + 1,1) - 1,1 · b

support

On the primary characteristic curve find a point corresponding to the optical density * - (3 _{0 <} ), which corresponds to the total exposure (+ H ^ ^{, p} + H? ^PE ). Consequently

-% ⁺ “L N; = H, ( _{0 <m} ).

Determine the parameters of additional dosed illumination of color negative film (claim 1) on the result of the tests (paragraph 2-5) and the results of the calculation of the layer-by-layer balance introduced by optics (paragraph 7) according to formula ⁷

where Γ · is the initial characteristic curve.

Determined by the calculated characteristic curve obtained by pg taking into account light scattering, the value of optical density corresponding to the point H _{o <>} i.e.

sr

0. "

'D ¹ ® ^<Η .ζ

one

Determined by p.d the gradient of the calculated characteristic curve by the formula

d. - - - _T - _,.

Choose as reference gradient

e ₀ ROHN = ^MIN KCH

Conduct a trial additional

40 metered illumination of color negative film.

Repeat sensitometric tests according to claim 2-5.

Calculated based on the results of densito45 metric measurements

coefficients and final parameters of additional dosage exposure.

Conduct final additional dosage of the entire

50 batches of selected color negative film of this type and axis.

Carrying out additional dosage flare on the proposed

55 way allows the operator to clearly

and uniquely manage the color and color characteristics of the motion picture.

I190348

1190348

Claims (1)

THE METHOD OF ADDITIONAL DOSED LIGHTING OF COLOR NEGATIVE CINEMA PHOTO MATERIALS, mainly when working with filming equipment, based on a preliminary determination of the sensitometric characteristics of the selected color negative? film photography before and after carrying out a test dosage exposure and determining the correction coefficients used to determine the final magnitude of the dosage exposure, which is the fact that, with the aim of expanding and information-. According to the optical and spectral characteristics of the used filming equipment, the amount of dosage illumination is determined by carrying out a preliminary filming of a reference source with a measured dosage on a white screen field on a color negative film. 5CP, 1190348 And 90348 2