The mystery of metal ink (on)

I remember that 20 years ago, the 20th anniversary of the freshman design school in Hong Kong was commemorated. Therefore, I wanted to have more eye-catching elements on the publicity materials. Since I had been working for several years, as in the past, Mr. Lu had a designer. After I came up with ideas, I first discussed with me those techniques that can be used and matched to achieve the best results.
As the designers at that time used a stationery to create a robot as a theme, the author suggested that it would be better to add a large area of ​​metal sensation, get a hot silver effect that exceeds the area of ​​A3 as the cover of the annual publication, and also have a screening hot silver. At that time, Hong Kong was able to burn such a large area of ​​hot stamping machines only two or three, and they all said that they had not tried to make such a large area of ​​iron.
In the end, because we had to catch up with the graduation exhibition, we had to make a hundred copies, and the others had to be solved by the printing of silver, that is, the version seen by the party, and Mr. Lu, the designer, and I, of course, collected the hot silver. The limited edition, I believe that there are not many people who have seen this hot silver version, and the metal ink used by Yinyin was very different from the current one, and its sparkling effect with hot silver is even more distant. If there are so many different metallic inks available today, there is no need to give up the original design, but unfortunately a good design does not have enough money and time and often cannot be achieved, and experience tells me that time is more expensive than money. important.
With the use of metallic inks, the effect can already be achieved by replacing more expensive materials such as aluminum foils or gold-plated materials. On the other hand, metal pigments are widely used, and metal effects can be achieved by different processes, such as replacing silver and the like. In the past decade or so, metal ink technology has also been greatly improved in terms of convenience and flexibility in printing, and it also has an advantage in cost. Since the content of the metal pigment in the metallic ink is generally 2 to 4 times more than the ordinary ink, the metallic ink is much more expensive than the ordinary ink.
In spite of this, ink printing is still welcomed by the packaging and printing industry because metal ink printing still has the advantages of faster production speed and lower cost compared with hot stamping and aluminized film printing processes. So now a lot of consumer product packaging, such as food, beverages, cosmetics, etc., are heavily used metal ink to stimulate the eye. It is also more convenient in application because it does not require the addition or modification of equipment, and it can be produced like ordinary ink, improving efficiency and saving costs. Of course, the printing process I am referring to is not just a lithography that Hong Kong people are familiar with, but also different technologies such as screen printing, flexo printing, and gravure printing.
What progress has made in metallic ink today? Let me start with the structure of metallic inks.
Metallic ink structure <br><br><br><br><br><br><br><br> Metallic ink (metallic printing ink) refers to the use of small metal foil instead of traditional inks in the pigment or dye formulated ink, with a metallic shiny effect. The general metallic inks are mainly gold and silver inks. Gold ink is generally added with copper pigments and zinc pigments. By controlling and changing their proportions, inks such as green gold, cyanine gold, and red gold are produced; and silver inks are formulated by adding aluminum pigments.
The optical properties of metallic pigments are different from those of ordinary pigments, so the optical properties of metallic inks produced are also very different from ordinary inks. The color of common inks does not change with the viewing angle, but the hue and brightness of metallic inks will change due to different viewing angles. Therefore, when using an instrument to measure spot-colored metallic inks, ordinary spectrodensitometers cannot be used. Instead, special spectrometers for measuring reflective metals are used. If it is not clear, color misunderstandings will often occur.
To match the printing method <br> The shiny effect of metallic ink is the result of the combination of specular reflection and diffuse reflection of metallic pigments. In order to achieve a better metallic effect, the specular reflection of the metallic pigment should be increased to reduce diffuse reflection. The effect of influencing the ink reflection is mainly the size of the metal pigment particle size. The larger the size of a single pigment particle, the better the mirror reflection effect and the higher the glossiness of the metal ink, but its hiding power and dot reproduction ability will become lower.
Conversely, the smaller the size of the metal pigment particle size, the higher the hiding power and dot reproducibility of the metal ink, but due to the excessive diffuse reflection of the edge, the gloss of the metal ink may be reduced. Therefore, the user needs to select the suitable particle size according to his own requirements, and the specific printing method must be used when selecting. Different printing methods will definitely affect the shiny effect of the metallic ink. (To be continued)