Gloss in print has long been sought after (matte prints are a rare exception). There are many printed matters that require varnishing, plastic coating, lamination, etc., the purpose of which is to improve the aesthetics of the printed matter. Of course, there is another layer of material on the printed matter, which also has the function of protection.
Once a layer of transparent material is added to a dull and dull printed matter, its effect will be greatly improved. So the effect of a print is closely related to its gloss.
Since the printed matter is coated with a transparent substance such as a layer of oil film, its color brilliance will be greatly improved (mainly due to the principle of optics), and it looks more spiritual. Therefore, improving the inner gloss of the ink itself has become a manufacturing process of oil sewers. the target of the reader.
The luster of an object seems to be a very common concept, but in fact it is a relatively complicated phenomenon, which is related to physical psychology. The so-called gloss of the ink actually refers to the ability of the printed sample of the ink (scratch sample not available) to reflect in one direction when it is irradiated by light. Although the evaluation of gloss can be compared by eye observation, the difference between them cannot be expressed numerically. This can be done with instruments.
At present, most of my country's ink industry uses a reflective gloss (degree) meter to measure the gloss of ink. This instrument is equipped with a fixed light source to shoot at the surface of the oiler printing sample at a predetermined incident angle, and then uses the photoelectric principle to measure the amount of light reflected from the surface of the printing sample, and compares it with the established standard under the same conditions. Compared with the amount of light reflected off the surface of the plate.
Since the ratio of the amount of light reflected from the surface of the ink print to the amount of light reflected from the surface of the standard plate is often expressed as a percentage, the gloss of the ink is also a percentage value.
(1) Equipment and materials
1 utensil. Reflective gloss (degree) meter (efleetanee Gloss Meter).
2. Materials. Ink proofs (solid prints).
(2) Method
A gloss (degree) meter generally has three main components, namely a gloss measuring head, a galvanometer (mostly a floating mirror light point type) and a standard blackboard.
The simple structure of the gloss measuring head can be seen in Figure 27-9, in which 1 is the light source, the light passes through the lens 2 to become parallel light, and hits the measured sample 5 at a certain incident angle α, the regular reflection light reflected by the surface of the measured sample (that is, the reflected light at right angles to the light emitted by the person) is projected on the photoelectric tube 4 through another lens 2 and the diaphragm, so that the photoelectric tube produces a photocurrent proportional to the amount of reflected light. The incident angle of the light source varies with the instrument, and the angle of the variable gloss measuring head can be from 15° to 85°, but most of the measuring heads used to measure ink gloss in our garden are 45° at present. For inks with higher gloss printed on the metal surface , you can choose the one with a smaller incident angle of the light source, because the smaller the incident angle of the light source, the more sensitively the high gloss can be distinguished. On the contrary, you can choose a measuring head with a larger incident angle of the light source.
The galvanometer is a kind of galvanometer used to detect the magnitude of the photocurrent generated by the photoelectric tube in the gloss measuring head. Most of them are of the light point reflection type, and it passes the detected current through the optical reflection device (floating Mirror) is reflected onto a scale with a 0-100 scale percentage.
A black standard is used as a comparison standard for gloss measurements and is usually a black polished flat glass plate. Its gloss standard is set at 100%.
The operation methods of such instruments are similar, and the operation steps can be roughly summarized as follows:
1. Turn on the power, turn on the switch, and let go of the protective device of the galvanometer pointer or floating mirror.
2. Adjust the pointer of the galvanometer or the light point of the floating mirror to the zero position with the zero point regulator of the instrument.
3. Adjust the induction controller to the "0" point in the counterclockwise direction, so as not to cause overload after connecting the gloss measuring head and damage the instrument.
4. Connect the gloss measuring head.
5. Place the gloss measuring head on the standard blackboard, and adjust the induction controller so that the pointer of the galvanometer or the hairline on the light point of the floating mirror is at 100 on the percentage scale (that is, the gloss of the standard blackboard is 100).
6. Move the gloss measuring head to the ink print, at this time the position pointed by the pointer or floating mirror light spot is the gloss number of the ink print.
