The implementation method of original color classification in sample printing is that the original is usually divided into CMYK four colors. If it is a color drawing or color photo, it is almost difficult to select the color on thousands of pictures. Therefore, the four-color printing method is usually used. That is, the original is color decomposed, divided into four-color (CMYK) color plates before printing, and the color is synthesized in the process. The traditional "color separation" is mainly a color separation process based on the principle of subtraction through the selection and absorption characteristics of different wavelengths of color. In this way, the color is filtered to form supplementary light, so that the photosensitive film forms a negative film of black-and-white image, and then screening to form a dot.

由于企業(yè)的大量應(yīng)用，現(xiàn)代印刷技術(shù)已經(jīng)不再使用上述的分色方法，現(xiàn)在我們通過印前掃描、取樣轉(zhuǎn)化的數(shù)字化技術(shù)，將原稿分解為RGB三色，通過電腦的數(shù)字化計算處理為CMYK即可實現(xiàn)分色。

Due to the extensive application of enterprises, the above color separation methods are no longer used in modern printing technology. Now we decompose the original into RGB three colors through the digital technology of prepress scanning and sampling transformation, and realize color separation by computer digital calculation and processing into CMYK.

圖像加網(wǎng)的原因與優(yōu)勢，印刷設(shè)備的固態(tài)確定決定了印刷只能采用網(wǎng)點再現(xiàn)原稿的連續(xù)調(diào)層次。如果我們有經(jīng)驗會發(fā)現(xiàn)，圖像放大若干，發(fā)現(xiàn)其是由大量的網(wǎng)點組成的圖案形象。

The reasons and advantages of image screening, the solid-state determination of printing equipment determines that printing can only use dot to reproduce the continuous tone level of the original. If we have experience, we will find that the image is a pattern image composed of a large number of dots.

因其占據(jù)同等大小的空間位置，盡管圖像網(wǎng)點大小不一定一樣大，為了避免這樣的工藝缺陷，我們通過對原稿圖像加網(wǎng)，通過網(wǎng)點中圓點大小來表示圖像顏色的深淺。

Because it occupies a space position of the same size, although the image dot size is not necessarily the same, in order to avoid such process defects, we screen the original image and express the color depth of the image through the dot size in the dot.

網(wǎng)點的空間位置和網(wǎng)點大小決定了產(chǎn)品的層次感，當(dāng)掛網(wǎng)數(shù)量更高，網(wǎng)點所占據(jù)的空間位置則越小，反之所占據(jù)的位置就越大，所能描述的層次就會減少，印刷成品就越粗糙。事實上，印務(wù)前原稿的色彩與層次都是通過這樣的形式掛網(wǎng)后被再現(xiàn)出來的。

The spatial position and size of the outlets determine the sense of hierarchy of the product. When the number of screens is higher, the smaller the spatial position occupied by the outlets. On the contrary, the larger the position occupied, the fewer levels that can be described, and the coarser the printed products. In fact, the color and level of the original before printing are reproduced after hanging the net in this form.