How to inspect the sample viewing process of the h

2022-08-10
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How to inspect the printing sample viewing process

the most common method used to check the printing quality during the printing operation. Whether it is monochrome printing so that the operator can query the test results according to the conditions or color printing, the operator must often use his eyes to repeatedly compare the print with the sample, so as to find out the difference between the print and the sample, and correct it in time to ensure the quality of the printed products. The following problems deserve our attention when looking at samples in printing:

first, the intensity of light directly affects the judgment of the color of printed samples

the intensity of light not only affects the brightness of the color, but also changes the appearance of the color

at ordinary times, we observe a light receiving cylinder. The light facing side is bright, and the backlight side is dark. The combination of light and shade is the middle tone

the same object is positive under the standard light source. If the light gradually becomes stronger, its hue will also change to a bright hue. When the brightness is enhanced to a certain extent, any color can turn white. The reflective point of black porcelain is also white, because the light at the reflective point is concentrated and strongly reflected. Similarly, the light gradually decreases, and various colors change to the hue with low lightness. When the light weakens to a certain extent, any color will turn black, because the object does not reflect any light is black. Table 1 shows the influence of light intensity on color

the sample viewing platform in the printing workshop must meet the requirements. Generally, the illumination is required to be about 100lx before it can be positive. 2. The experimental machine should be installed horizontally on a solid foundation, and its installation levelness should be better than 0.2mm/1000mm to identify the color

II: there are differences between sample viewing under colored light and that under sunlight

in production practice, most of them work under the irradiation of power supply, and each light source has a certain color. This brings some difficulties to correctly judge the color of the original or product. When viewing the color under color light, the color change is generally the same color becomes lighter and the complementary color becomes darker, such as: viewing the color under red light, red becomes lighter, yellow becomes orange, green becomes ASTM G105 SAE recommended Practice (Falex dry sand/rubber wheel apparatus) and other standards are dark, blue becomes dark, white becomes red

when viewing color under green light, green becomes lighter, green becomes lighter, yellow becomes green yellow, red becomes black, white becomes green

when looking at the color under yellow light, yellow turns light, magenta turns red, blue turns green, blue turns black, and white turns yellow

when viewing color under blue light, blue becomes lighter, blue becomes lighter, green becomes darker, yellow becomes black, and white becomes blue

in the printing workshop, fluorescent lamps with high color temperature (3500~4100k) and good color rendering coefficient are generally selected as the sample viewing light source, but it should be noted that fluorescent lamps are slightly blue and purple according to Hooke's law

III: the results will be slightly different if you look at the sample first and then the print and then the sample.

you will feel different when you look at one color twice. This phenomenon is called sequential color contrast reaction, and the changes are shown in Table 2

why is there a sequential color contrast reaction? This is because the color you look at first excites the color nerve fibers of that color, and then look at other colors immediately. Other color nerves are soon excited to cause color sensation, while the color nerves that look at color first are in an excited and then inhibited state, and then excited slowly, causing a negative hue reaction. This reaction, coupled with the hue of the new look color, forms a new color, so it changes the look color. And the hue of the change is still regular, which is to change the complementary color of the first look color

to understand the above three aspects and their change rules, we should pay attention to them when we actually look at the samples, so as to ensure the stability and improvement of the quality of printing products

the change trend of the color that the eye looks at first and then looks at again

red, yellow, green, blue, purple and white

lateritic, red and green, yellow, fresh green, green, blue and blue, slightly green

yellow, gray, yellow, green, green, green, fresh blue, blue, purple and purple, slightly purple

blue, yellow, green, gray, blue, red and purple, light orange

purple, lemon, yellow, green, green, blue, gray, purple, green and yellow

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