In recent years, the printing volume of color papers has been increasing rapidly. Compared with integrated printing companies, due to the characteristics of the management structure and printing requirements, professional color printing companies often involve more factors in color and image control. For example, the source of image manuscripts is complex and the quality is very different; because of the small color gamut formed by the printing suitability of the paper and ink used for printing, the color quality of RGB manuscript itself is very different (as shown in Figure 1). The difference in color gamut); and because many small and medium color printing press papers and inks are frequently replaced, the prepress processing time is tight, and color proofing and printing control are not performed, resulting in large fluctuations in color and image quality. . Figure 2 shows a color report color and image quality control process used by the author in practice. The core of the program is the addition of screen soft proofing to the front of the process based on the traditional control links (red arrows) and parameters. The process link (shown by the green arrow) is based on the premise of satisfying the real-time performance of the color print, and the visual inspection and visual editing of all modifiable colors and images entering the process flow through the soft proofing of the screen. Meet the printing effect of the best or specific style required for a particular output condition (such as a combination of paper, ink, machine and other factors), thereby greatly increasing the performance and quality control of colors and images that require high real-time performance in the copying process Predictability and operability. With a price of less than 10,000 yuan, the color and image quality of many tens and millions of color newspaper hardware systems can be guaranteed and enhanced. To form the above-mentioned quality control link based on soft proofing, the key is to establish the screen based on the printability characteristics of the existing phototype platemaking and color newspaper web production lines, and the screen can truly reflect the effect of the color report. The color management process, which requires the following aspects of the work. A blackboard (also known as a Chalkboard) is a reusable writing surface on which text or drawings are made with sticks of calcium sulphate or calcium carbonate, known, when used for this purpose, as chalk. Blackboards were originally made of smooth, thin sheets of black or dark grey slate stone. Wooden Chalkboard,Wooden Blackboard,Wooden Sandwich Board,Chalkboard Sign Jinan Tri-Tiger Technology Development Co., Ltd , https://www.jinanfurniture.com
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A blackboard can simply be a board painted with a dark matte paint (usually black, occasionally dark green).Matte black plastic sign material (known as closed-cell PVC foamboard) is also used to create custom chalkboard art.Blackboards on an A-frame are used by restaurants and bars to advertise daily specials.
A more modern variation consists of a coiled sheet of plastic drawn across two parallel rollers, which can be scrolled to create additional writing space while saving what has been written. The highest grade blackboards are made of a rougher version porcelain enamelled steel (black, green, blue or sometimes other colours). Porcelain is very hard wearing, and blackboards made of porcelain usually last 10–20 years in intensive use.
Lecture theatres may contain a number of blackboards in a grid arrangement.The lecturer then moves boards into reach for writing and then moves them out of reach, allowing a large amount of material to be shown simultaneously.
The chalk marks can be easily wiped off with a damp cloth, a sponge or a special blackboard eraser usually consisting of a block of wood covered by a felt pad. However, chalk marks made on some types of wet blackboard can be difficult to remove. Blackboard manufacturers often advise that a new or newly resurfaced blackboard be completely covered using the side of a stick of chalk and then that chalk brushed off as normal to prepare it for use.