The hottest special printing 11. Stereoscopic prin

2022-09-23
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Special printing (11) stereoscopic printing

today's largest stereoscopic printing is the large stereoscopic animation display screen of the Tokyo Olympic Games, and the smallest stereoscopic printing is the Apollo lunar landing stamps issued by Bhutan. At present, the three-dimensional printing materials often seen in the market are mostly Postcard sized, as well as New Year cards, picture books, product catalogs, decorations, etc. No matter what kind of stereoscopic printing, it should be printed by one of the stereoscopic printing technologies below

stereoscopic printing of double photo method

when two identical photos are placed horizontally at a distance between two eyes, you will get a stereoscopic feeling, which is also the principle of the most classical stereoscopic printing

the so-called stereoscopic printing of two photos is to put two photos together and use a special viewing box (see Figure 1), or glasses, or the naked eye to see the printed matter with stereoscopic feeling

historically, this method is very old. It was invented after the invention of self illumination. The production method of the manuscript is very simple, that is, put two cameras together and shoot at the same time. If it is a stationary subject, you can also take two consecutive shots with one camera, just slightly stagger the angle of the same subject. After that, put these two photos side by side. Later, it will be the same as ordinary plate making and printing. Use the usual color printing

with the photos taken by two photography methods, even without stereoscopic glasses, stereoscopic images can be seen with the naked eye. This is called "stereoscopic viewing with the naked eye", which opens a convenient door for enterprises hiding flammable and combustible problems. It can be roughly divided into "parallel method" and "staggered method", and the differences are explained in detail later

parallel method and interleaving method

for these two methods, it takes a little skill to watch them clearly

1. Parallel method

the so-called parallel method is to look at the image on the right with the right eye and the image on the left with the left eye, as shown in Figure 2. First, look at the nearby objects in the state of focusing in the distance. At the beginning, I always feel a little faint. Looking at the original faint object gradually conforms to the focal length, and soon I see a clear three-dimensional object. At this time, the distance between the object and the eye is preferably 1.8m

2. Interleaving method

again, interleaving method, to the state of esotropia, use the right eye to see the image next to the left eye, and use the left eye to see the image next to the right eye. As shown in Figure 3, if you make the left and right images coincide while staring, you will suddenly feel that the original flat screen highlights the stereoscopic sense. The distance between the picture and the eyes should be 80cm

no matter the parallel method or the staggered method, it takes patience to master certain skills when seeing stereoscopic images with two eyes, but once you are proficient, you can easily watch a variety of stereoscopic images

the average distance between human eyes is about 65ram, so the distance from the center of the left and right pictures to the center is less than 65mm, which is the best viewing distance. In addition, the largest size of the three-dimensional is based on the size of the postcard

recently, from an original or photo, with the help of computer processing for special image processing, it has been possible to make an original that can be seen as three-dimensional

hologram

this is a special and very popular process method that can take three-dimensional effects. Developed in 1962, the laser is diffused to the subject through the convex lens, and the light reflected from the subject reaches the film surface. Another beam of light irrelevant to the subject, namely, the reference light, also reaches the film surface after being reflected by the reflector. After the two parts of the laser are overlapped, thin lines called interference lines are produced. When you zoom in with a microscope, you can see that hundreds of thin lines are recorded in a place 1mm wide. A film with such thin lines is called a hologram. Using laser to irradiate the hologram, the image in the line can be reproduced, and the hologram can be made and reproduced, which is generally called holography

1. play the role of anti-counterfeiting

usually, holography refers to the method of using interference lines to represent stereo images. Holograms are divided into multiple transmission type, rainbow type and other types

the multiplex type is to see the stereoscopic image in the cylindrical transparent film. 360 is 5.6 percentage points higher than the industrial added value of national industrial enterprises. No matter from which angle you can see the stereoscopic image, it can be said to be a real three-dimensional image, and it can also make the image show the characteristics of activity

rainbow type is an image of rainbow color when viewed under white light, so it is named. By embossing, mass production can be carried out on film or transfer foil. If processed on transfer foil, 5 μ M thickness, so it is difficult to forge with the help of copying

in view of this, holograms are often used to print seals, credit cards or tickets for sports conferences and concerts to prevent pirated video software, and can also be used as seals with adhesive coated on the back. Figure 5 is an example

2. Making method of hologram

laser should be used when shooting the original. Light must have the wavelength property of a certain period, and the coincidence of two beams of light has the property of mutual interference

when the laser phase is complete, the interference lines formed with the light irradiating the laser (reference light) and the reflected light reflected from the three-dimensional object are recorded on the photographic film. The specific method is to use a semi reflector to divide a column of laser into two beams. The so-called semi reflector is a lens that allows half of the light to pass through and the other half of the light to reflect. One of the two laser beams is cast on the subject, and the reflected light is recorded on a high-resolution dry board. At this time, when projected onto the subject, the reflected light with phase shift and the reference light with complete phase interfere with each other and become interference lines to form a stereo image

the rainbow hologram shows the interference lines of light in the form of concave and convex, and the fine concave and convex recorded on the high-resolution dry plate are sprayed with metal to make a metal prototype. Use this metal mold to heat press the transparent polyester seal. According to this, a large number of holograms can be made repeatedly

after that, if aluminum is evaporated on the embossed surface sealed by transparent polyester, the stereoscopic image can be seen by the light reflected on the embossed surface

in addition to making physical models for shooting, holograms can also be made from three-dimensional images drawn by computer graphics. This is the use of computers to calculate the interference lines during light projection, which can be applied to holograms

two color stereoscopic printing

when viewing this kind of stereoscopic printing, you must use special two-color glasses, as shown in Figure 6

1. red and green are the key points

as long as you wear red and green cellophane glasses, you can see three-dimensional prints. Generally speaking, looking at the printed matter itself, only red and green are printed by misplacing the same picture. Wearing glasses pasted with red and blue cellophane gives you a three-dimensional feeling

the eyes on the side of the red cellophane see the red printed picture, which is a technique to use this kind of eye illusion to express the suspected three-dimensional

there are also three-dimensional films made using this principle. It can no longer be said that only printed matter has this kind of expression. In addition, from the perspective of printing alone, Neco printing (New enlarging color operation) can now be used to produce oversized prints. At present, it has been applied to large posters or advertising screens outside the house

2. stereoscopic printing that cannot show continuity

the production method of two-color stereoscopic printing is particularly simple, using photography or the original painting depicted, and printing with two-color dislocation. In order to set off the sense of distance, the width of dislocation is divided into 5 ~ 6 stages

the regret of two-color stereo printing is that you can't see three-dimensional images without wearing red and blue glasses. Moreover, because it is a technique to express the sense of distance and proximity in several stages, it can't express continuous three-dimensional

to say that the printing cost of two-color printing is not expensive, but the color filter of glasses should use high transparency quality, plus the type and processing cost of glasses, the total cost is relatively high. Nevertheless, as a technique to appreciate the simple stereoscopic screw image, it can still be said to be quite popular. Cylindrical stereolithography

this is stereolithography using concave convex cylindrical mirrors,

is also the most common stereolithography at present

1. stereoscopic printing without tools

when viewing with stereoscopic glasses, some people are not good at watching, or they can't see the picture clearly without stereoscopic glasses. According to the viewing environmental conditions, they are easy to be affected by personal differences

compared with this, there is a simple way for anyone to value three-dimensional. This is the method of using a plastic called cylindrical lens to make concave convex convex lenses with a thickness of less than 1mm and paste them on the printed matter with the gradual warming of the power market, and then seeing the object image with the right eye and the left eye respectively to feel the three-dimensional, as shown in Figure 7

for images used for cylindrical mirrors, if you want to use a stereo camera dedicated to stereo printing to shoot objects, you must align the lens with the images used for the right eye and the left eye, interlace them, and make plates correctly. The pattern itself is mostly printed by four-color offset printing. When the printed surface is mounted with plastic sheets, the cylindrical mirror is formed at the same time. The pre made column lens can also be spliced to the surface of the print with transparent adhesive. However, this method is more labor-intensive. It is reported that there is a more advanced method, that is, the plastic film is shaped into a cylindrical mirror while being printed on the surface of the printed matter

2. Change the viewing angle. The picture also changes.

the reason why stereoscopic printing of cylindrical lens is regarded as stereoscopic is that the cylindrical lens sends stereoscopic information to the left and right eyes from all angles. This stereoscopic printing effect has been widely used in color postcards, invitations, display screens, packaging and so on

in addition, as an example of the application of cylindrical lenses, changing the viewing angle produces a continuous sense of image movement, which is called "pocket animation". It is often used in the appendix of children's magazines. At this time, it is not limited to the two kinds of information for the right eye and the left eye, but also can be combined into a completely different picture of the third kind

3. Production of three-dimensional moving laminations

now, we can not only print three-dimensional pictures, but also print dynamic pictures on this basis. It is a thin concave convex plastic plate with a concave convex spacing of 0.6mm on the same picture. Depending on the different pixel lines reflected to the left and right eyes, or changing the viewing angle, the viewer can see a moving picture in an instant, or two pictures with different pictures and related contents. For example, if you look at a closed box from the left, it will become an open box from the right

for another example, from the left, it is a girl with eyes closed. If you move your position a little, you will become a girl with eyes open, as shown in Figure 8

how is this dynamic animation printed? First of all, we need to prepare a different animated photo, which is 18 film frames overlapped and made into one photo at a time. Take this photo as the original, add a concave convex thin transparent plastic plate in front of the photographic plate of the camera, and then place a 300 line, inch screen in front of this plastic plate at an appropriate distance. When everything is arranged properly, the reflected light of the photo passes through the screen and plastic plate and reaches the photosensitive sheet, that is, a photographic negative composed of pixel lines is made. With this plate making and printing, it can be made with dynamic

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