What is printing dot

What is printing dot

As we all know, people working in the printing industry have had more or less contact with dots, and mastering a wealth of dot technology is essential.

What are outlets?

Dot: The basic printing unit that constitutes a continuous tone image. The contrast between this image unit and the blank space on the printed matter achieves the effect of reproducing continuous tone. According to the screening method, it is divided into AM dots (AM dots: the image level is expressed by the size of the dots, the dot spacing is fixed, and the dot size changes) and FM dots (FM dots: the image level is expressed by the density of the dots rather than the size of the dots)

What are the functions of the network points?

Dots are the basis of the printing and reproduction process and the most basic unit of graphics. The main functions of dots are:

1) Responsible for the color, brightness and saturation of printing effects;

2) It is the smallest unit of lipid sensitivity and water repellency and is the basic element of image transmission;

3) In color synthesis, it is the organizer of image colors, layers and contours.

How to identify the percentage of outlets?

The dot is the basic unit to achieve the natural division of the printed product in terms of the different levels of the published surface and the shades of the color scale (light and dark). It plays a role in determining the color, level and image outline of the printed product. Therefore, only when the dot size is accurate during plate making can the original color be faithfully reproduced, ensuring that the printing process achieves a good effect.

Since the lightness and darkness of the printed page is expressed by the size of the dots, dots of different sizes are technically called "dots". Only by accurately understanding the concept of dot ratio can we better use dots to print out printed products that are closest to the original color. Therefore, knowing the dot ratio is knowledge that printing operators and quality inspectors should master. There are two ways to identify the dot ratio: One is to use a densitometer to measure the integral density of dots, and then convert it into a percentage of the dot area. For example, if the integral density of dots is 0.3, the dot area is 50%. This method is more scientific and accurate.

Another method is to use a magnifying glass to visually measure the ratio of the dot area to the blank area. This method is more intuitive and convenient, but due to experience, the error is large. Specifically:

The identification of the percentage of dots within 50% is based on the number of black dots of the same size that can be accommodated in the gap between the two black dots on the opposite sides. That is, if three black dots of the same size can be placed in the gap between the two black dots on the opposite sides, it is a 10% dot;

If the distance between two dots can accommodate two dots of the same size, it is called a 20% dot;

If 1.5 dots of the same size can be placed between two dots, it is called a 30% dot.

If 1.25 dots of the same size can be accommodated between two dots, it is called a 40% dot.

If there is a dot of the same size between two dots, that is, the black dots and white dots occupy half of the unit area, that is, 50% dots.

The judgment of more than 50% dots is measured by how many white dots of the same size can be accommodated between two white dots on opposite sides. According to the dot arrangement rules, the number of dots contained in the distance between two white dots is exactly the same as 60% and 40%; 70% and 30%; 80% and 20%; 90% and 10% respectively.

The above situation shows that the so-called dot ratio is the percentage of the unit area. For example, 10% dots are 10%, 20% are 20%, and so on. 100% is the solid layout. From the rough analysis of the arrangement of dots in the positive film, if the black dots are larger than the white dots, it is more than 50% dots; if the black dots are smaller than the white dots, it is less than 50% dots. The larger the dot ratio, the darker the ink color of the printed layout, and vice versa. The size of the dot area determines the change of the layout level. Usually, the levels on the picture are divided into three gradation levels, that is, the high-tone level is composed of 10% to 30% dots, forming a bright part on the picture. The middle tone level represents the transition between light and dark parts of the picture, usually composed of 40% to 60% dots. The dark picture composed of 70% to 90% dots is the low-key level. The brightest place on the printing plate, that is, the highlight part, is less than 10% dots.

To sum up, only by accurately understanding the proportion of dots can we better utilize the law of dot changes, produce printing plates that conform to the originals, and print color printing products with accurate colors and satisfactory quality. This is also the goal of quality management.