1.  The intensity of light directly affects the color of the book printing sample sheet. The intensity of light not only affects the light and shade of the color, but also changes the appearance of the color.

Usually we observe a receiving cylinder, the side of the light is bright, the backlight is dark. The combination of light and dark is the middle tone. The same object is a positive color under the standard light source. If the light gradually becomes stronger, its tone also changes to the bright hue, the light increases to a certain extent, and any color can become white. The reflection point of black porcelain is also white, because the reflection point is concentrated and strongly reflected. Similarly, the light gradually decreases, all kinds of colors change to low brightness hue, light weakens to a certain extent, any color will become black, because the object does not reflect any light is black.

2.      There are differences between the color light and the sunlight. In the actual production, most of them work under the irradiation of the power supply, and each light source has a certain color. This brings some difficulties to the correct judgment of the original or product color, color under the light, color changes are generally the same color lighter, darkening,

The fluorescent lamp with high color temperature (3500~4100 k) and good color rendering coefficient is generally chosen as the sample light source in the printing workshop, but the fluorescent lamp should be slightly blue and purple.

3. First look at the book printing sample sheet and then look at the print and then look at the sample sheet, the results will be slightly different, two times to see a color when feeling different. This phenomenon is called sequential color contrast reactions

Why is there a color contrast reaction? This is because the first color makes the color nerve fiber excited, immediately look at other colors, other color nerves quickly excited to cause color sense, and the first color nerve is in the state of inhibition after excitement, and then the excitement is slow, causing negative color reaction. This reaction, coupled with a new color, forms a new color, so it changes the color. And the change of hue is still regular, is to look at the color of the change.

The change in the color of the eye first and then the color of the eye

Print is divided into monochrome printing, color printing. Monochrome printing is limited to one color printing method. Color printing can print full color pictures. Most color book printing uses color separation plate to reflect all kinds of color, color separation plate is composed of red (M), yellow (Y), blue (C) and black (K) four-color network plate. Color separation plate color can be based on the principle of color separation, directly with the text to indicate the number of CMYK spots in the chromatography. When special colors are required, use special colors other than these four colors and set up spot colors. The color identification of the spot color version can specify a certain color phase in the chromatography, specially debugged.

Print is divided into monochrome printing, color printing. Monochrome printing is limited to one color printing method. Color printing can print full color pictures. Most color printing uses color separation plate to reflect all kinds of color, color separation plate is composed of red (M), yellow (Y), blue (C) and black (K) four-color network plate. Color separation plate color can be based on the principle of color separation, directly with the text to indicate the number of CMYK spots in the chromatography. When special colors are required, use special colors other than these four colors and set up spot colors. The color identification of the spot color version can specify a certain color phase in the chromatography, specially debugged.