What are the steps of stereo printing
The process of stereo printing is generally divided into four steps.
Step 1: stereo photography
There are two common methods for photographing stereoscopic printing originals:
(1) Circular arc stereo photography: the cylindrical lens plate is installed in front of the photographic film to take photos, the optical axis of the camera is aligned with the center of the object to carry out circular arc movement with an included angle of 3-10 degrees, the grating plate in front of the photographic film of the camera moves synchronously with the photographic film at random, after exposure, it is focused into a pixel under each half cylinder of the grating plate, when the camera finishes shooting at a predetermined distance, the pixel is full of the entire grating Distance, three-dimensional photos can be obtained by developing.
(2) Shutter moving method: when shooting, the moving distance of the shutter is about equal to the distance between two eyes (60mm), and the grid plate also moves correspondingly, the moving distance is a grid distance (0.6mm).
Step 2: plate making
The following points need to be paid attention to in the process of three-dimensional printing plate making:
(1) The offset plate making method is usually adopted for stereoscopic photos. Considering the fine pixel of stereoscopic image and the amplification effect of cylindrical grating, the net line density shall not be less than 300 lines / inch.
(2) Since the three-dimensional original is composed of closely arranged pixels, and after plate making and printing, it is necessary to composite column mirror plate. Therefore, the angle of three-dimensional printing and common color printing plus screen is different. In order to avoid moire, three-dimensional printing with different grid spacing should have different combination angles of yellow, magenta, blue and black screen lines. Among them, the angle of blue plate and black plate can be the same, If the three-color printing ink is close to neutral gray after overprinting, in order to reduce the error caused by the fourth overprint, it is not necessary to print the black plate.
Step 3: printing
The paper used for three-dimensional printing must be compact, smooth, flat, small flexibility, and bright and clean without fading after printing.
Generally, high-precision four-color printing machine is used, and the workshop should have constant temperature and humidity conditions.
Step 4: composite column mirror plate
After printing, the surface needs to be covered with a column mirror plate to have a three-dimensional sense. There are two kinds of cylindrical lens grid plate: hard plastic and soft plastic. When the width is large, hard plastic is often used.
Three dimensional printing has the following characteristics:
1. The image has a strong stereo sense.
2. The original of three-dimensional printing can be made of modeling design or scenery shooting, and ink printing is heat-resistant.
3. The surface of the printed product is covered with a layer of concave convex column mirror grating plate, which can directly watch the three-dimensional effect of the panoramic picture.
4. The overprinting must be carried out according to the plan to avoid the paper stretching, resulting in inaccurate overprinting.
Three dimensional printing elements mainly include:
(1) Paper: the paper for three-dimensional printing is required to be compact, smooth, flat, and has small flexibility, and the copperplate paper and paper jam are widely used.
(2) Grating material: mainly including hard plastic and soft plastic three-dimensional grating.
Hard plastic solid grating has high refractive index and good luster.
The soft plastic grating has good chemical corrosion resistance, but its thermal stability and light resistance are poor.
(3) Ink: because any visible degree of foaming will affect the clarity and three-dimensional effect, so three-dimensional printing ink is not foaming ink. The curing temperature of three-dimensional printing ink conforms to the curing range of plastic ink. After the ink layer is cured, three-dimensional printing ink has the same good elasticity as standard plastic ink. The image printed with this ink has distinct fine layers and clear edges, which are suitable for fine layers and screening quality.
(4) Adhesive: the function of the adhesive is to make the printed matter and the grating firmly stick together, and to protect the ink layer from discoloration under high temperature.