Printing proofs are the most commonly used technique to check the printing quality during the printing control process. Regardless of whether it is monochrome printing or color printing, the operator must always compare the printed product and proofs for his own eyes to find out Real-time correction of the difference between printed products and proofs to ensure the quality of printed products. The following exceptions are worth paying attention to when printing samples:
One: The intensity of light directly affects the discrimination of the color of the printed sample. The intensity of light not only affects the brightness of the color, but also changes the appearance of the color. Usually we look at each light-receiving cylinder, and the side facing the light is Bright tone, the side of the backlight is dark. The combination of light and dark is the central tone.
The unified object is a strong color under the standard light source. If the luster gradually becomes stronger, its color will change to a bright hue, and the smoothness is enhanced to the necessary level. Any color may be changed to white. The reflection point of a black porcelain dish is also white. , Because the light gathers at the reflective points and reflects violently. Similarly, the brilliance gradually decreases, and each type of color changes to a low-brightness hue. The light is weakened to the necessary level, and any color will become black, because the object does not reflect any light. It is black. The sample stand in the printing shop must be suitable, and usually the illumination reaches 100LX, so the color can be accurately identified.
Two: There is a difference between looking at samples under colored light and looking at samples under sunlight. In the essence of production, countless occupations are mapped under the power supply, and each type of light source has the necessary color. This will send accurate identification of the color of the manuscript or product. Bring necessary setbacks, color viewing under colored light, color change is usually the same color becomes lighter, and complementary color becomes darker, for example: red color viewing, reddish light, yellow to orange, green to dark, cyan to dark, and white to red Viewing color under green light, green becomes lighter, cyan becomes lighter, yellow becomes greenish yellow, red becomes black, white becomes green. Viewing color under yellow light, yellow becomes lighter, magenta becomes red, cyan becomes green, blue becomes black , White to yellow. Color viewing under blue light, blue to lighter, cyan to lighter, green to darker, yellow to black, and white to blue. In printing shops, the color temperature is usually higher (3500 ~ 4100K), and the color rendering coefficient is relatively A good fluorescent lamp is used as a sample light source, but be aware that the fluorescent lamp is slightly blue-violet.
Three: first look at the proofs and then the prints and first look at the prints and the proofs, the truth will be slightly different, and you will feel the difference when you look at which type of color twice. Such a sign is called the front and back color comparisons. What about the color before and after? This is because the color that looks first makes the color nerve fibers of that color happy, and then immediately looks at other colors. Suppressing the form, and then slower and happy, leading to the negative color reverse. Such a response adds the hue of the new color to a new color, so the color of the back view is changed. Moreover, the changed hue is still regular, and the color is viewed first. Changes in complementary colors.
Knowing the above three or more aspects of the anomaly and acquainting with their changing rules, we should pay attention to the actual sample, so that we can guarantee the stability and improvement of the quality of printed products.