At present, there are a lot of small and medium-sized printing manufacturers are using monochromatic offset press to overprint color live, simple printing overprint turquoise, generally speaking overprint single four color is in the majority, but also some printers overprint of positive and negative eight color. This will request printing machine high quality, high precision, but also request printing operators a superb technology, and in the overprint process should pay attention to the printing color sequence of reasonable arrangement:
General four-color machine printing color sequence of reasonable arrangement way is: black, blue, red, yellow, also have to pour color sequence yellow, red, blue, and black printing. Four color printing machine, between color and color printing interval is short, the ink no drying time, belongs to the wet pack wet superimposition way, and monochrome printing machine when between color and color printing interval is longer, printing the second color, the color has been dry, so belong to wet pack dry superimposition way, because of the different ways of superimposition, color sequence arrangement is also different. Monochromatic machine color sequence arrangement forms a lot, but specific to choose which color sequence can be respectively from the aspects as follows to consider:
1. According to the three primary colors lightness to arrange color sequence must first printing, printing dark light, i.e., blue, black, red, yellow first printing after printing.
2. According to the three primary colors printing ink transparency and covering power arrangement color sequence, transparency poor blue, black, yellow, good transparency first printing ink printing after.
3. According to the graphic area size to arrange color sequence is first printed small graphic, after full version printed or substantial surface graphic.
4. According to the original features, with warm color attune is given priority to color images must first printed blue or black, and cold tone is given priority to with the colour picture first print red or yellow.
5. The overprint to consider, the first printing overprint difficult color. General printing landscape in the blue, yellow sequence printing, but the character image, according to titian sequence printing.
Using monochromatic machine printing four color printing color when live suggested sequence: blue, red, yellow, black, so, as long as the first two color overprint accurate, color is good, the back of the two color overprint even a little no nor too obvious. The operator should pay attention to when changing ink, to maintain the purity of print, cleaning grey ink is finished or finished, best can add a few the printing of the color ink, afresh again clean again. Especially dark ink in light color ink, best can machine cleaning twice. (Gold Printing Group)