Best printing image resolution calculation 2

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Print image resolution calculation

1 The digital image processed by the computer is also called "dot matrix graphics". You can think of dot matrix graphics as graphics composed of many square color blocks of different colors,

and each square color block of different colors is called pixel

2. Resolution refers to the number of points or pixels contained in the unit length of a digital image

for example, an image with a resolution of 100 points per inch is called 1oodpi

(dots per inch) which sometimes adopts stress waveforms such as triangular and rectangular waveforms

3. In some digital image processing software, every point is called a pixel,

so the unit of resolution is also called PPI (pixels per inch),

whether it is DPI or PPI (DPI, which is a more general unit),

from the impression of traditional printing photos, we can know that the finer the particles of film and paper,

the finer the image quality that photos can show

Since the digital image is composed of pixels, the higher the resolution is, the better the quality of the digital image will be

therefore, it is conceivable that the image quality of 300dpi digital image will definitely be better than that of 72dpi digital image

4. Before scanning the image into a digital electronic image file,

the output resolution and image magnification of the printed product must be determined first

5. [magnification] is the ratio of the print ruler of the image to the original size

6. The resolution of printed matter is usually based on the number of lines per inch in the unit length,

varies with the type of printed matter and the type of paper. Generally speaking:

newspaper: 85lpi

Color magazine: 133, 150 or 175lpi I heard that the composition of this material is very simple

art album: 200lpi

6 Generally, when we use the paper with smooth surface such as snow copper paper as the printing material, we will choose the resolution of

300pixels/inch (DPI) or 118pixels/cm (DPC)

for digital image printing. Such image resolution can reach the line number quality of 150 lines per inch when used in printing

7. On various types of prints, the digital image resolution used,

depends on the print line value applicable to the print material

if you want higher line number quality, the resolution of the digital image needs to be increased.

generally, you can multiply the line value by twice, that is, the resolution value of the digital image

if the image needs to be enlarged, it must be multiplied by the magnification, as shown in the following formula:

scanning image resolution = number of printing lines X 2 x magnification

for example, in order to reduce the number of vibration lines of harmful vehicles caused by train operation, the image must be enlarged by 3 times,

then the scanning resolution must reach 9oodpi (150lpix2x3 times)

another example: when the printing line is marked as 175lpi, if you want to print the image with the original size, it is best to scan the image with the resolution of 35oppi

if you want to enlarge the image twice for typesetting and printing, you should use the scanning resolution of 70oppi

7. When processing black-and-white line art, the scanning resolution should be the resolution of the output device

for example, when you want to output 12oodpi black-and-white photo paper, you should take 12ooppi as the scanning resolution

if only 300dpi electric printer is used as output, 30oppi can be used as scanning resolution

source: lead screw and nut as performance parts, China Art and Design Union

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