http://www.printing-in-china.cn/shownews.asp?id=1968
Withdraw light agent is a kind of oil cream of shape colorless transparent material, and in the special color printing of main up diluted the role of color. The addition amount from light agent, the influence of different hue is different also, especially the most obvious blue performance.
In the configuration is in the process of color ink, well ink meter, the exhibition ink apparatus to produce the ink shearing force, pressure than the small printing machines. In printing doesn't need to withdraw, but with light agent in ink color swatches make only light agent to join removed, hit even designed the color color display card. In the same color density, color and print showing a color is the color difference exists, it is because the light agent to withdraw, changed the printing ink pigment distribution state, the ink the absorption of light by refraction and reflection are changed, which produce the off color, the color difference is by the differences of the system.
Dry density differences. The influence of the refund
Just printed out the printing, printing ink is still in the wet state, and the dry state has a density difference. Wet color, density is more than dry color density of the phenomenon is called dry density back phenomenon. This is because just printed out the ink layer has certain flow ping sex, so the surface reflection mirror to give priority to, colorful, gloss. When ink layer in dry state, surface diffuse reflection to give priority to, colour and lustre is nature than just printing out appear to be gloomy.
Due to the dry color density in general to finish in Indian dry 30 to 60 minutes later, it can measure to special color density measurement, control more difficult.
With a polarizer device can eliminate the density meter is designed ink layer surface of specular reflection and produce light, and the color of the wet and dry density color density is close, make the measurement of density values from ink layer dry wet effect. For coating paper, measuring density difference of 0.05 ~ 0.15, the coating of measuring density difference paper for 0.1 ~ 0.2. Different color is different also, the yellow color, black is the largest, minimize differences between blue and red between them. So the use of such when measuring the density meter is designed, measured value than the standard shall be the appropriate color sample density value, so that we can play a part of higher control function.
The influence of the system differences
Use well ink meter, the exhibition is the process of making ink color is "dry stamp", and there was no water in the process, and printing is "wet printing" process and wetting liquid participate in process, so in the offset printing ink is bound to happen in oil-in-water emulsions, emulsion of emulsified phenomenon after ink pigment particles in the with the changing of the ink layer distribution state, must produce off color, printed out the product also is gray, not bright-coloured colour and lustre.
In addition, allocate special color of the ink used stability, ink layer thickness, weighing the accuracy, printing ink for the difference between the old and new, printing ink, the printing speed on the amount of the color difference will produce different effects.
Of special color control
To sum up, in order to guarantee of different products, with the color difference conform to the state standards and customer's requirements, we in the printing process to the special color made this control.
1. Color swatches make
First of all the clients according to the standard sample with the color, computer color matching systems are special color ink ratio; To call up with small kind, ink and ink meter, the show is "show" the ink color samples of different density; Then according to the national standard (or to the requirements of customer) color range, with spectrophotometer determine standard, shallow limit, deep limit, making printing standard color card (color difference exceeds bid to be further fixed). Color is half and half are common color sample after surface treatment of color sample, this is for convenient use, such as quality shown the appended drawings.
2. Verify special color
Considering the influence of off color paper is the major factor, so every time before printing with actual printing paper "show" color sample, the comparison color correction, to do the eliminate the influence of the paper.
3. Printing control
The printing machine used standard color printing brought to designed the color layer thickness control, and aided by measuring the density of density meter is designed color value and Bk value, to overcome ink dry, wet color density differences.
In short, in the packaging and printing, causing the cause of special color produce off color various, and should in the actual production of different specific reason analysis, problem solving, as far as possible the deviation control in the least scope, produce customer satisfaction packaging printing quality.(Gold Printing Group)
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