The computer has now become an important tool in the screen printing process department, which can help enterprises reduce a lot of time-consuming preparation work, but there are still many difficulties in making full use of the functions of the computer. Here is an example to illustrate the problem. A job that seems very simple when it comes in can become more and more tricky over time. For example, a series of small transparent paper backing prints are used as product identification for electronic instruments. The overall design includes a more complex Logo and some text, which needs to be printed in two colors on a background color. The customer gave us a disk with instructions to contact the designer if there was any problem. When you first look at these files, you see that all of the image elements were created by Photoshop software. The first question is why do they create files in Photohshop?
Admittedly, Photoshop is a powerful piece of software, and many printers are happy to use it for four-color printing. But it is a bitmap software, screen printing department in the processing of bitmap software generated by the manuscript will always encounter a lot of trouble, let's look at the specific reasons. Raster and vector According to the internal principles used in graphics image processing software to create an image and the type of file generated, they can be divided into two categories: bitmap and vector. Bitmap software creates an image by dividing it into small, easily observable squares that are either light or dark according to the density of the image. As shown below. The representative software is the drawing software in the Windows operating system. Adobe Photoshop is an advanced bitmap software.
The image composed of a bitmap is produced by rasterization (the term comes from television, and the scans that make up a television picture are often called rasters). Because a bitmap image consists of a large number of small squares formed by rows, the sharpest lines in the image occur closer to the x or y axis. (Dots near a single column in the vertical direction, dots near a single row in the horizontal direction) When you look closely at lines or curves that are at an Angle to the x or y axis, you will find that there is a sawtooth phenomenon, because the program simply inserts a predetermined image path by closing or opening small squares in the grid. In other words, the program cannot draw smooth curve edges. The resolution of the bitmap image is determined by the size of the small square. The smaller the square, the clearer and clearer the curve edge. If you zoom in on a bitmap image, the degradation rate of the image visually appears to be very fast. Because when the grid is enlarged, the right-angled edges of the squares will become more and more obvious. Although it is possible to reproduce a bitmap image at a higher visual resolution, it is necessary to realize that the spatial information of the objects in the bitmap image is relative (because the resolution is different, the size of the image is also different), and it is impossible to know the absolute size and location of the objects in the bitmap image. This fact poses a great difficulty for industrial screen printers. Spatial information is crucial to correct engineering drawings.
In fact, spatial information in digital form is the object of engineering drawings, and it is also the difference between other forms of printed matter and engineering drawings. In ordinary print, the size and position of objects are not so important. For half-tone or four-color printing, software that produces bitmap images is important. Because in half-tone or four-color printing, the level simulation is the primary work, and for the engineering drawing that requires the degree of spatial stability, the level is very unimportant. This does not mean that bitmaps play a small role in the production of drawings, and many times a rasterized image, such as a scanned icon (Logo), can be added to the overall design of industrial graphics. At this time, the size and position of the image can be determined according to the visual effect, and the operation is simple and time-saving. Bitmap software can be used as a design tool for initial concepts, or for product advertising design and other similar graphic products, such as product catalogs.
With this information in mind, it becomes clear how limited the Photoshop images we can get from our clients are. We can only get the general design and color arrangement from this, but we can't judge the actual size. Nor can we import the files into any software that can make the film on demand and separate the colors.
While there are several ways to import bitmap images into those assembly software, in this particular case we had to choose to recreate the original in vector software. A digital process vector is a oriented, mathematically expressed quantity, in addition to representing the size of the number, the vector is also a unit of test. The key is to have a digital input.
