Gold and silver ink printing materials and application analysis (2)

Gold and silver ink printing needs to be printed according to the special needs of the product to achieve the desired gold and silver printing effect. If the surface smoothness of the paper is better, the metallic gloss of the print will be better; if the surface of the paper is rough and porous and the texture is loose, a good metallic luster printing effect cannot be obtained. The use of coated paper and calendered white paperboard is generally preferred. The effect of offset paper is poor, and the effect of letterpress paper is even worse. Although the surface gloss and smoothness of glass paperboard are better, gold and silver inks are used to print, large areas of gold, silver, and silver cover the white light brightness of the paper itself, and the characteristics of glass paperboard are weakened, so they should not be used. .

The reason for choosing coated paper and calendered white paperboard for printing gold and silver inks is that they have:

1. Have a higher degree of smoothness. Because printing the silver on silver paper with higher smoothness, the reflection coefficient of the surface of the printing ink is larger than the reflection coefficient of the printing paper on the paper with poor smoothness, and the gold and silver light of the print is striking. And the outlets are clear, rich in levels, and bright in color.

2. Small ink absorption performance. We know that when the ink-absorbing performance of the paper printed with gold and silver is large, the binder in the ink is absorbed into the paper by a large amount, causing the ink to dry and accelerating. The leveling property is poor and the imprinted surface is not smooth. The gold and silver powder loses the linking material. The protection floats on the surface of the paper and imprints irregularly, pulverized, etc.

3. Strong surface strength. In the printing of gold and silver ink, in order to transfer gold and silver finely, a binder having a relatively high viscosity is used, and if the printing is performed with a paper having a low surface strength, a surface picking phenomenon occurs, which affects the printing quality. Coated paper and calendered white paperboard have strong surface strength.

4. The pH is moderate. Copper powder and aluminum powder in gold and silver ink are chemically active metals. If acid paper is used, acidic substances in the paper will react with the gold and silver powder to destroy the fineness of the metal powder and affect the quality of the printed matter. The coated paper and the calendered white paperboard meet the requirements of moderate pH.

(D) Gold and silver ink printing

1The relationship between printing and design of gold and silver ink and plate making

In order to obtain better results for gold and silver ink printing, pre-press design and plate making must take into account the special requirements for gold and silver ink printing.

When designing, you should try to avoid overprinting of the main colors and large areas on the ground so as to avoid the possibility that gold and silver inks will not be printed or the ink will be printed.

Gold and silver inks are printed in the last color.

Gold or silver is designed as far as possible in dark, blue, black and other dark colors on the ground, forming a strong contrast between bright metallic and dark ink, in order to bring out the metallic bright effect of gold and silver.

Gold and silver ink printing lines, text can not be too small, this is because the particles of gold and silver powder in the transfer process of printing ink transfer performance is poor, likely to cause heap plate, paste version, resulting in small lines, text blur clear.

On the same printing plate surface, it is not appropriate to design a large area of ​​real printed gold and silver with fine lines and text. In general, when printing large areas of gold and silver in the field, the pressure of printing will be large, which will affect the fine lines and the clarity of the characters; if you consider the fine lines, the clarity of the text and reduce the printing pressure, it will inevitably affect the thick gold and silver in the field. And flatness.

In order to solve the attachment of other color graphics to gold and silver on the ground, the parts of the gold and silver printing plates that need to be overprinted are designed to be blank.

2 The relationship between gold and silver ink printing and background

Prior to the printing of gold and silver inks, a background color is generally printed. The ink color of the background ink is good or bad, which directly affects the printing quality of gold and silver ink. The reasons are:

(1) The gold and silver powders of gold and silver ink are relatively large and the printability is not as good as that of ordinary color inks, and there is a drawback that the adsorptivity is poor. The use of ink at the bottom before printing can enhance the adsorption capacity of gold and silver ink.

(2) The first printing of the background color is more conducive to bring out the metallic luster of the gold and silver ink, eliminating the possibility that the impureness of the whiteness of the paper may affect the color of the gold and silver ink.

(3) Firstly, the background color can be used to fill the capillary pores on the surface of the paper and reduce the ink absorption performance of the paper, thereby making the printed gold and silver inks more bright and eye-catching.

Gold and silver inks are generally based on yellow ink, yellow ink has two kinds, one is transparent yellow, should be used for coated paper as the background color; the other is yellow, generally used in offset paper as the background color. It can also be used

(commonly known as fake gold) ink as the background.

The ink at the end of the printing must master the dryness of the ink layer to apply the desiccant. Because the bottom ink is completely dry, the gold and silver inks that are overlaid on the ink will stick poorly. If the bottom ink does not dry, the gold and silver inks that are overprinted will be damaged and affect the luster of the gold and silver inks. The actual printing of gold and silver ink is generally performed when the background ink is dry and non-dry. Therefore, if the bottom ink is found to be too slow to dry, an appropriate amount of dry oil can be added to accelerate the drying speed; if the bottom ink is found to be too dry, an appropriate amount of dibutyl phthalate can be added to slow the drying speed. A suitable amount of bright oil can also be added to the bottom ink to make the conjunctiva smooth and strong, and increase the affinity between the gold and silver ink and the bottom ink.

3 gold and silver ink printing

The printing equipment used in the printing of gold and silver ink and its operation method are basically the same as the printing of the color ink. However, attention should be paid to the characteristics and requirements of various printing processes and corresponding measures should be taken.

(1) Letterpress gold and silver ink printing process

Plates use metal bottoms. Plates must be flat, firm, and accurate.

The ink roller adopts a soft and elastic ink roller with smooth surface and smooth surface.

Printing pressure should be strictly controlled. The pressure is too big to cause the back of the paper to have bulges, blots and ink, the pattern is blurred or deformed; too light causes the printed material to be not clean, not eye-catching, unflattering, and the imaginary flowers are not clear.

Pay attention to the relationship between printing speed and pressure. Because the increase in printing speed will inevitably lead to reduced contact between the printing plate and the paper, and ink transfer will be affected. Therefore, when the printing speed increases, the printing pressure also needs to be increased. Only such adjustment can make the printing plate and the paper contact well, and the ink is smooth. Transfer.

In the field printing, the two printing methods of printing the bottom ink are generally used. The formula for printing gold ink should be selected according to the texture of the paper, for example: Generally 50% dark yellow, 50% transparent yellow. If the paper is soft and the ink absorption is good, dark yellow can be properly increased, such as dark yellow 70%, transparent yellow 30%.

Toppan printing ink also has a variety of formulas, such as 1800 mesh gold powder 50%, 30 to 90 oil transfer oil 50%, moderate amount of dry oil; 2800 mesh gold powder 50%, 05 to 90 light 30%, moderate amount of dry oil, No. 0 Adjust

Ink oil 10%, dibutyl phthalate 10%. (to be continued)