Shaiban and traditional proofing and digital FM proofing technology knowledge

☆ What is the role of proofing? (1) Check the quality of each process of plate making;
(2) Providing the review basis for the client;
(3) Provide ink, specifications and other test data for the official printing.

☆ What is a print version? Shaiban refers to the application of contact exposure method, and the graphic information on the anti-original plate is transferred to the photosensitive plate, and after a certain processing process, the proofing plate or the printing plate is manufactured.

☆ What are the methods of printing?
The main methods of printing are:
(1) Divided according to the original type: positive print and negative print;
(2) According to the printing version: single drying and set drying;
(3) According to the type of printing plate: flat rotogravure and PS plate printing.

☆ What is the printing process of the positive PS version?
Loading plate (including original positioning, pad plate shading and airtight sealing) --- exposure --- development --- revision --- ink --- eraser.

☆ What is the impact of the size of the exposure exposure on the dot quality?
Before the plate-burning personnel perform daily operations, they must use standard ladders to calibrate the exposure and development time, and develop drugs.
Under the condition of constant development conditions, increase the exposure and narrow the dot; reduce the exposure of dot expansion;
Exposure beyond the normal range, too much will lose the high-profile level, too little will make the tone too full, dark tone network blur.

☆ What is the purpose of hanging the paper before it is proofed?
The first is to eliminate the moisture, deformation, etc. caused by climate change and other factors in the production, packaging, transportation, storage and unpacking of paper, which can cause overprinting inaccurate printing;
The second is to adapt the paper moisture content to the working environment temperature and humidity, and to reduce the paper's sensitivity to the working environment's temperature and humidity and layout moisture, which is conducive to the further stabilization of the paper's moisture content, so as to achieve the purpose of overprinting accurately.

☆ What is the main ingredient of ink?
The ink is mainly composed of a pigment, a binder, an auxiliary agent and the like.

☆ What are the main properties of ink?
The main properties of the ink are: concentration, fineness, viscosity, fluidity, light resistance, water resistance and alkali resistance.

☆ How to mix ink?
When dispensing ink, be sure to:
(1) Hue conforms to the sample
(2) Has the proper viscosity and fluidity
(3) Appropriate amount of dry oil
(4) The quantity of ink transferred shall be based on the quantity printed, ensuring that the quantity is sufficient for use and that there is a slight surplus.

☆ What should I pay attention to when deploying ink?
(1) Choose an ink with good texture, pay attention to the nature and hue of the original ink;
(2) A detailed analysis of the original color and a strict calculation of the ratio of the original ink to the added diluent;
(3) Full consideration shall be given to the nature of the printed paper, the temperature and humidity of the work environment, and the specific performance of the proofer;
(4) When darkening the color ink, the number of primary color inks should be minimized, otherwise the brightness of the ink and the vividness of the ink color will be reduced;
(5) When light-colored ink is adjusted, primary color ink should be gradually added in the diluting agent, and no diluting agent can be added in the primary color ink, otherwise, it is likely to cause inaccurate hue and waste of ink.

☆ There are several kinds of blankets?
There are two kinds of rubber blankets: ordinary rubber blankets and air-cushion blankets.

☆ What are the requirements for the quality of blankets in printing?
(1) The blanket should be uniform in thickness to ensure uniform pressure during graphic transfer;
(2) It should have good elasticity so as to ensure the good ink-absorbing performance of the graphic and text transfer effect;
(3) It has a small elongation to reduce the amount of deformation when the text is transferred;
(4) Good ink absorption and transferability to ensure that the printed ink is uniform and clear;
(5) Has good oil resistance, heat resistance, acid resistance, alkali resistance, wear resistance and aging resistance, in order to extend the service life of rubber and reduce costs.

☆ What is the role of the ink roller and water roller?
The role of the ink roller is to transfer and beat the ink; the role of the water roller is to transfer and mix the fountain solution.

☆ What is a control signal? (Process Control Stript)
The control signal strip, or signal test strip, is one of the important tools for data management of the printing process.
It is typically composed of typical outlets, fields, lines, and special markers.
The control strip is mainly used to detect the copying of the film, copying, proofing or printing.

☆ What is the role of the control signal bar?
The main function of the signal strip is:
(1) Reflect whether the printing degree is moderate;
(2) Reflect the presence or absence of ghosting;
(3) Reflect the expansion rate of outlets;
(4) Reflect the density of the field;
(5) Reflect overprint accuracy;
(6) Reflects the color effect.

☆ Why do we have to measure field density values?
If it is necessary to correctly reproduce the gradation of the film and reflect the neutral gray balance, it is necessary to strictly grasp the density value to ensure the stability of the plate making and printing quality.

☆ What are the key points for correct field density values?
The correct field density value should be mastered:
(1) Neutral gray balance of three primary colors;
(2) The network expansion rate is normal;
(3) The outlets are well restored.

☆ A proofer, after relocation, re-installation, what to debug?
(1) Empty car operation, check the machine for abnormal noise, and whether there is any special vibration;
(2) Use 40-60 lines/cm of full-scale 50% dots, plus signal strips for printing, proofing, check whether the dots are solid and clear, and check the dot enlargement rate of each part;
(3) Full-size proofing on the spot to see if the ink color is uniform, flat clothes, and whether there are ink sticks;
(4) Registration, checking the crosshairs around, including the registration of the mouthpieces and their registration.

☆ What is stress?
Pressure refers to the pressure exerted on the transfer of graphics on the plate to the printed paper during proofing.

☆ How did pressure get?
The pressure comes mainly from:
(1) Obtained by adjusting the center distance of the roller;
(2) Obtained by adjusting the thickness of the lining.

☆ How to identify the size of proofing water?
Identify the size of the water, first look at the layout of the water; generally speaking, the water is large, the amount of light reflected in the layout, side view is brighter; the contrary, the layout of the light is weak, side view is dark;
In addition, the following points can also identify the size of the proofing water:
(1) Scoop ink on the ink roller with a knife, leaving fine beads on the ink blade;
(2) The layout often appears dingy;
(3) The imprints are empty.

☆ What is digital FM color proofing technology in desktop publishing?
Digital FM proofing refers to the copying of proofs from the assembled graphic information through standard data control techniques;
Its basic role is to obtain color calibration proofs before actual printing.

☆ How to control the field density in digital FM sampling?
Under the premise of fixed raw materials, normal machine condition, and normal environmental control, the relative K value of the contrast is used to determine; the actual field density corresponding to the maximum K value of each color version is the actual field density under control at the time.

☆ In digital FM sampling, how to calculate K value?
K=D Solid-D75% Dot/D Field☆ How is digital FM color proofing classified? What are their characteristics?
Digital FM color proofing can be divided into offset proofing and non-offset proofing.
The general offset proofing is the use of a platform type offset proofing device. There are monochrome, two-color, four-color models, etc. It uses data control technology to make the image color reproduction and tone reproduction reach a certain standard;
Its characteristics are simple equipment, low operating costs, data control technology is easier to grasp, good quality;
Non-offset proofing can be divided into a variety of proofing methods, and is now widely used in desktop publishing, electronic publishing and desktop prepress processing.
(1) The soft proofing system displays the color copying effect through the color CRT monitor. It is one of the indispensable devices for the electronic color image and the color DTP system. Its feature is that it does not require the use of films, printing plates and other consumable materials, and the proofing cost is low and the speed is fast. Effort
This proofing system is the so-called "WYSIWYG" (WYSIWYG).
(2) The hard proofing system can be divided into two categories, namely, "digital proofing" that directly uses color separation data using "chemical proofing" of color separation platemaking.
Chemical proofing:
Refers to toner proofing and color film proofing, which is characterized by stable proofing quality and easy operation, but the proofing cost is higher and the speed is slower;
Digital proofing:
It can use a color dot matrix printer to achieve needle punching;
Use color inkjet printers to achieve continuous inkjet, ink mechanical frequency vibrating inkjet, atomized continuous inkjet, pulsed pressurized inkjet, thermal expansion inkjet, etc.
Use thermal transfer printers, thermal sublimation printers, silver salt photo printers, digital color copiers, etc. to achieve a variety of color proofing.

Reprinted from: Printer