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Inventory: eight color knowledge that affect the printing effect

eight color knowledge of printing:

1. Color consistency. An important way to ensure color consistency is to let customers observe color samples and printing samples under standard lighting conditions and obtain their approval. 3. Fully automatic sample clamping. In order to reduce the changes of color in the process of transmission and reproduction, the printing industry has specially formulated standard color observation conditions, that is, standard color observation pool (a light source control area with a stable environment set up for observing samples or other prints)

this color observation pool has two key elements: one is lighting (color temperature is 5000K); The second is neutral gray environment (munselln8)

it is very important to check the color on the observation pool, because the lighting conditions and surrounding environment when we check the color will affect our perception of the color. If there is no standard observation pool, we can also watch the samples in the indirect sunlight

2. Influence of lighting. When we observe colors under different lighting conditions, we see different effects. Another problem we need to pay attention to when observing colors is the same color spectrum. The so-called metamerism is that when two samples are in one light source, the color is the same, while in another light source, the color is different

when observing the color, it is very important to keep the lighting conditions stable and consistent. The reason why we choose a light source with a color temperature of 5000K is mainly because this light source is a mixture of red light, green light and blue light, which can provide a stable and consistent observation environment for people

3. Influence of surrounding environment. Do we observe whether the surrounding environment when printing samples will affect the color? Proximity color, that is, the color similar to the observed sample or print, can affect people's perception of color

this is the so-called critical effect, which to some extent reflects the importance of using a neutral environment when observing samples. It is understood that the use of standard gray paint (munselln8) in the surrounding environment can effectively reduce the influence of adjacent colors on people when confirming colors

4. Paper. Subtraction refers to the method of mixing yellow, magenta, cyan and black inks in a white environment (usually paper). In the process of color reproduction, one element will have a significant impact on the printing effect of color, that is, paper

the same ink color may produce different printing effects on different papers. The whiter the paper, the larger the gamut that can be reproduced on the printer. If the baidu of paper is not enough, then the color gamut it copies on the printing machine is relatively small

5. Spot color. Each spot color corresponds to a special ink (except yellow, magenta, cyan and black), which needs to be printed by a separate printing unit on the printing machine. There are many reasons why people use spot colors in printed matter. One of them is to highlight the brand image of an enterprise (for example, Coca Cola's red should initialize the setting parameters before the power on test machine or Ford's blue). Therefore, whether a spot color can be accurately copied is of great importance to both customers and printing plants

another reason may be the use of metal inks. Metal inks usually contain some metal particles, and can make printed matter show metallic luster. In addition, when the color requirements of the original design exceed the color gamut range that yellow, magenta and black can achieve, we can also use spot color to supplement

6. Convert the color to CMYK. When we convert the color of an image from RGB to CMYK, we usually generate halftone dots of black ink through two methods, one is background color removal (UCR) and the other is gray component substitution (GCR). Which method to choose mainly depends on the number of yellow, magenta, cyan and black inks to be printed in the image

base color removal refers to the removal of a part of the base color from the yellow, magenta, and cyan primary colors to form a neutral gray, that is, the approximate black base color formed by the superposition of the three primary colors of the pigment yellow, magenta, and cyan, and replaced by black ink. Background color removal mainly affects the shadow area of the image, not the color area. When the image is processed with the method of background color removal, it is easy to appear color deviation in the printing process

gray component substitution is similar to background color removal. Black ink is used to replace the gray formed by color ink overprint, but the difference is that gray component substitution refers to that the gray components within the whole tone range can be replaced with black. Therefore, when the gray component is replaced, the amount of black ink is small, and the image is mainly printed with color ink. When the maximum replacement amount is used, the amount of black ink is the largest, and the amount of color ink is reduced correspondingly. The image processed by gray component substitution method is more stable in the printing process, but its effect also depends on the color adjustment ability of the printer operator to a large extent

7. Technical terms. The reason why we think color is difficult to describe is mainly because it is a feeling. Just as smell, taste and hearing must constantly optimize the mixing proportion of graphene, this feeling cannot be described in words. When we have to use words to describe color, we often use vague words such as dull, muddy, too warm or too cold

for example, what is the image too warm? Is it red, yellow or magenta in color? What does it mean to be too cold? Is the color of the image too blue, too green or too green? When we say that an image is flat and light, we usually mean that its contrast is not enough, while turbid consciousness means that the tone of the image is too dark. The use of non-standard terms will prolong the proofing cycle, thereby delaying the production progress of live parts. Therefore, we must use professional terms when talking about color - this can save you a lot of time and money

8. Printing is not a complete matching process. What is replication? Replication is not an exact match, but infinite proximity. Printing is not a complete matching process, mainly because there are many color reproduction systems in the color reproduction process. Photography is a typical color reproduction system, as is proofing and printing