Analyze the Secrets of Printer Ink and Paper (I)

Through years of practical experience and continuous exploration, I have summarized some details and in-depth knowledge about ink, printing paper, etc. I hope to help everyone understand ink, ink and various types of paper! At the same time because we are not specialized in ink and paper research. What we can dedicate to us is only the experience we have accumulated in these many years and some details revealed by professionals. Therefore, there are inadequacies in the hope that all of you will come together to explore and jointly improve common progress is our goal!

Printing ink

The ink color is provided by two types of materials, one is a dye and the other is a pigment.

Dyes are characterized by being transparent, by changing the color of the transmitted light by selectively absorbing certain spectral components of the incident light. Therefore, dye ink can be used not only to print color photos, but also to print transparent light box pieces. Traditional color photographs, transparent positive films are dyed to color.

The original materials of many kinds of dyes are insoluble in water, so some special solvents are required to dissolve them first and then add water. Some of these solvents that dissolve dyes are detrimental to the materials that make up the ink head. I commissioned a company to develop yellow ink five years ago. As a result, the ink supplied to the ink head soon became damaged. After analysis by the company's experts, it should be the solvent that dissolved the yellow dye to destroy the ink head.

The durability of the ink is basically determined by the original material of the dye. It is not known which dye is more durable. In addition, we do not know what kind of dye it used to formulate the ink we bought. I think the basic principle is definitely that more expensive inks are generally more durable. Because the raw material of the dye is so cheap, it must have certain defects. Insufficient durability is definitely one of the major defects. The reason for your price is basically more durable, and the color may be special. There are fewer people.

Magenta in EPSON dye inks is a less durable color. We used it to print color cards on matt paper. We found that if exposed to the air, we don't need to see the light. As long as one month, the color will fade and the grayscale will become green. The EPSON ink imitation of some manufacturers is even more terrible. After printing it tonight, if it is not coated, it will fade the next morning.

Ink is used in different printers and other things are added to change its viscosity, surface tension, and possibly its coefficient of thermal expansion or boiling point, to enable different printers to be ejected smoothly. These additives should also be safe for the ink head. .

Solvents and additives used on different printers make different printers have different options for paper. As we all know, the EPSON dye ink printer picks up paper, but if its ink is replaced, it can be used just like an HP printer.

In formulating compatible inks from different manufacturers, we discovered that most inks are not formulated with one dye. The phenomenon is that the color saturation of most inks sold in the market is higher than that of the original ink. We usually use two or three inks in combination to match the color of the original ink.

Pigment inks were formerly made by grinding mineral pigments. Today's pigments may also have non-mineral materials. In general, it is made of solid pigment and then emulsified to make ink. Its main feature is that it is more durable and the more granular the more durable it is. It is less transparent. It can also be seen from the bottle of ink, it is a bit like milk. Therefore it cannot be used to print transparent films. Because it is opaque, its composite color: red, green, and blue are also less saturated.

No oily ink is used in small printers. Only large outdoor sprayers use oily ink. This type of ink is similar to printing inks, but printing inks usually use transparent dyes, while outdoor sprayers use inks formulated with pigments. The nozzles of outdoor sprayers are very large and are not easy to clog. This ink uses organic solvents and film formers like paint. The surface of the material is very low. Not only is it resistant to water and light, it is not very good quality.
Ink color matching problem

Since most of the software is designed based on the original ink, the color should be closer to the original ink when using the alternative ink unless you can modify the software yourself. According to our observation, the so-called method of using ICCProfie correction, even if using an expensive colorimeter, the effect is very amateur.

The similarity of ink color is also mainly three parameters: hue, color saturation and concentration. We usually use several inks to formulate its parameters in line with the original ink.

It is more difficult to deal with other factors

Since human eyes can also give people an illusion of observation, the matching of the colors of yellow, blue and green does not mean that the colors mixed with these inks are the same as those of the original ink. The reason is that it looks the same color, and its absorption spectrum may not be the same. Therefore, the absorption spectra produced after the mixing of the two types of dyes are definitely not the same, and the resulting colors may not be the same. Mainly in the red, green and blue colors are not the same. Therefore, when selecting the original ink, we must also take care of the matching of the three mixed colors. If the six colors match well, the rest of the problem is not great. Because in the printing software, the color is mainly based on these six colors by adding color to construct other colors.

Printing paper and matching with ink

Let's discuss reflective printing paper first. The main purpose of the printing paper coating is to absorb the ink faster and prevent the ink from spreading laterally. Ordinary offset paper has good ink absorption capability, but it does not prevent the lateral spread of the ink, so the clarity of the image is not high and the color saturation is extremely low.

We may often notice that the surface of the plaster or whitewashed wallcovering is also very ink-absorbent and the ink dots spread less. So we use something like gypsum powder to make the coating and the print quality will be better. Paint paper is such a thing. Of course it may not be coated with gypsum powder. It is made of some white powder mixed with some binder. There are many holes in the middle to absorb the ink. After the ink drops, it spreads in the depth and horizontal direction. Compared with offset paper, its horizontal diffusion is smaller, so the clarity and color saturation are better. In addition, its porosity is relatively large, no matter what kind of ink can be absorbed. However, after the ink's moisture evaporates, these pores become an unobstructed channel for air to enter, so the photos printed on coated paper fade faster. Pictures printed with HP printers will fade more than 30% after one year. Coatings on coated papers are not yet strong, and they can be thrown off when lightly stroked, and they cannot be protected by lamination.

Another disadvantage of the coated paper is that the diffuse reflection caused by the rough surface structure makes the maximum density of the photograph not reach a very high level, usually only reaching the level of 1.6, sometimes reaching 2.0 with special black ink. However, due to the opaque coating, the level of dark areas is not good.

Print papers developed with coated paper as the basic technology are known by many as silty coated paper. Although the degree of ink dot diffusion is different, their defects are common.

The glossy photo paper used for printing is very different from the coated paper, especially the glossy photo papers used in traditional printers such as Hewlett-Packard and NOVAJET. If we use a bit of water on it, the coating on the surface will become sticky. But it is also transparent, and it makes us feel like it is a kind of animal glue. However, the current coating is probably made of high-molecular organic compounds. It will not use the cow bone glue or pig skin glue used on the film. When a drop of ink dripped onto the top, we noticed that the coating swelled significantly after absorbing water. Obviously this "glue" absorbs moisture and dye molecules into its own microstructure and softens and swells itself. A good coating does not absorb ink faster, but it absorbs ink more slowly, and the surface tension of the coating is also relatively large, so that the ink droplets do not infiltrate into the surroundings like water droplets on the lotus leaf when they are not sucked into the "glue". Then slowly inhale the "glue", after the water evaporates, the "glue" body shrinks and the dye is tightly wrapped.

The thick printing paper has strong ink-absorbing ability, and the diffusion to the horizontal is also small. This type of printing paper can be printed with a relatively large amount of ink. The printed photographs are sharp and sharp, the density of the dark portions is large, and the layers are transparent and beautiful. We once bought a paper that had been coated twice and printed well. Our recently-customized canvases were coated twice.
How to look thin coating? Printing with the same amount of ink, if the dark part of the same density, and the middle of the dark color is a thin coating or ink dot diffusion of paper. After the amount of ink is increased, the paper with a low density in the dark part must be a paper with a large dot spread or a thin coating.

Since the coating is completely transparent, the ink can form a large concentration, and the incident light is reflected after entering the bottom layer, and after two times of filtration, the color saturation is high. In addition, since the ink dots spread little, they can be perfectly colored by a pure additive method. Therefore, the saturation of high-brightness red, green, and blue is very high.

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