FR2478335A1 - System of relief effect photography - involves use of double negatives taken with offset and use of intermediate grille plates - Google Patents

Abstract

The system produces transparent images, giving an impression of relief. Two successive views are taken of a three dimensional object. The optical axis is displaced parallel and the two negatives are fixed together to obtain the offset effect positives. The two positives are fixed together. An intermediate transparent part (3) is used with a negative grille (1), complementary to the positive (2) one and the superimposed surfaces, are fixed together. When taking the negatives a negative grid (2) is superimposed on the unused film. The amount of offset depends on the contrast desired.

Description

The present invention relates to instruments which allow the highlighting of a transparent image from its photographic originals.

There are other highlighting methods that are
- - Stereoscopy, visualize through polarized glasses
- The anaglyphs, see through See-Buse two transparent and chromatic screens
- A system of parallel lines engraved on a plate of transparent material directly applied to a binocular image.

These processes entered
- either a lack of comfort for viewing the relief,
- - either fatigue for the eyes,
- either the use of equipment that is too expensive for industrial production.

The highlighting according to the invention avoids these drawbacks. It is in fact associated with the photographic system in its most elementary form and uses conventional equipment, The reading of the image, is done without intermediary. It is a direct relation between the "image light" and the eye. To obtain this highlighting, we will proceed as follows
We take two same shots by shifting the optical axis of the camera, parallel to itself. The distance varies according to the sides of the subject to be photographed. Preferably from 5 to 20 mm.

 The printing is carried out by positioning the blank film on the exposure plate of the enlarger or of the reproduction bench.

 A frame is used with the characteristic network due to the perpendicular crossing of two lines and the transparent squares obtained by this crossing have the same width as the black lines. The ratio of this screen is therefore 1 to 1. The positive of this screen, the linearity of which is 25 lines per cm or 57.5 lines per inch, is applied to the blank film.

 We put the first negative in the film carrier.

 The film is developed by observing an average contrast difference of 1.25 in density.

 We put the second negative in location on the first in the film carrier, before removing x this one. The exhibition and development process will be the same as for the first film.

 The two positive films, obtained in the half-tone negative frame system, are superimposed, making the subjects and the two frame systems one on the other as best as possible. We shift a line in the direction of the diagonal of the transparent points, taking care to make each semitone point of an image appear in the white reserve of the other image.

We will possibly match the whole to form only one image (1/1 Fig. 2 sketch 2- 1/2 Fig. 4 sketch 4-4 ')
We will thus observe a positive frame, by the combination of the offset of the two images and a binoxular image integrated into a positive frame thus formed by black dots.

 A transparent material with a thickness of 1.5 to 2 mm is applied to the binocular image. The format of the material corresponds to the format of the image.

 The original weft is applied to the transparent material (black white) which was used to execute the positive to integrate the semitone positives. Its function is to provide parallax with the binocular image and to create interference (1/2 Fig. 3).

 We will appreciate the relief after a good inclination of this frame.

We will thus observe the image, with the elements assembled in
this order and taking care to put a diffusing material behind the plate. (preferably white) (1/1 Fig. 2
1/2 Fig. 4)
1/2 Fig. 3 Reading principle
I) 4 = image of the left eye.

 4 '= image of the right eye.

The images perceived by each eye are said to be monocular.

 II) Framing (grid or grid) on the corresponding single-image images of sketch I.

 III) Assessment of the monocular system of each eye of the images 4-4 'of sketch I through 2-2' of sketch II.

 IV) Result at brain level on the unification of images; a binocular image is thus obtained.

 Fig. 4 Reading appreciation.

 1-1 'Eyes in direct communication with the brain.

2-2 'Frame ensuring parallax, by its space with the basic image 4-4', p for the appreciation of the image corresponding to each eye and of the interference obtained.

 It makes it possible to obtain, through the unification of images, a three-dimensional expression.

3-3 'Result on the sensation of relief in the brain 4-4' Basic binocular image recorded in a frame system.

This system has the advantage of being inexpensive, of being easily reproduced and thus allowing a wide distribution.

It can be suitable for light type panels
- advertising
- preventive (general security).

It may also be suitable for the observation of all binocular documents on a negatoscope, or viewer.

The process can also find its application in underwater, terrestrial and aerial photography.

This process can satisfy the graphic arts by the attractive side of the relief design and the field of printing for its execution.

Claims (3)

REVEhDICATIONS 1) Process for producing transparent images, giving the observation, the feeling of the relief, characterized in that  we take two successive shots of an object  three-dimensional by shifting the optical axis of shooting  parallel to itself; we draw each negative by inserting a 1 on 1 screen in contact with the sensitive film, we superimpose the two screened positives obtained by shifting the images in the diagonal direction of the transparent points, we fix the two positives together, or we perform a counter-type of this assembly (1/1 Fig. 2 sketch 2).  A transparent intermediate is superimposed (1/1 Fig. 2 sketch 3) and a negative weft grid complementary to the positive weft of ratio 1 on 1 and we fix together the superimposed surfaces.  2) Method according to claim 1 characterized in that at the time of printing of the two negatives, it is superimposed on the report frame. 1 on 1 another frame with a coefficient lower than 2.5 to 3.  3) Method according to claim 1 characterized in that at the time of the prints of the two negatives, one superimposes on the blank film at a variable distance, according to the contrast difference that one wants to obtain from the negatives, a negative screen of 1 on 1.