Halftone dots are the smallest units in offset printing. They are invisible to the naked eye and require magnification for clear visibility. These dots, determined by size and density, crucially influence the color, outlines, and shades of printed material, especially when reproducing halftones and colorful prints in offset printing.
In offset printing, the primary colors used are CMYK (Cyan, Magenta, Yellow, Black). The plate-making process involves using software to analyze the proportions of these four colors in the graphics and text. Subsequently, four separate plates are created. Each plate corresponds to one color ink well. During printing, the machine overlays these dots onto the paper. It blends them to recreate the original content.
It’s important to note that these dots have specific angles. This is because the dots of the four colors need to be evenly distributed on the paper surface. It can avoid overlapping and create unintended colors, such as black. Typically, the angles of the four-color dots differ by 22.5 degrees, with common angles being 0 degrees, 15 degrees, 45 degrees, and 75 degrees. For example, if a manuscript contains a lot of skin tones, the angle of a specific color dot might be set to 45 degrees. Conversely, for manuscripts with a predominance of sky blue, another color’s dot angle may also be set to 45 degrees.
Yellow, due to its lower luminance compared to other colors, is often set to 0 degrees or 90 degrees. However, because yellow is less pronounced, a larger angle setting may be necessary. Prolonged observation of yellow under artificial light in a printing plant may also lead to visual difficulties.
Therefore, the correct setting of the angles for the four-color dots is crucial. It can ensure accurate color reproduction and avoid any issues with color overlay during the printing process.
