Print image resolution calculation

1. Digital images processed by computers are also referred to as dot matrix graphics. You can think of dot matrix graphics as a combination of squares of many different colors. Each square has a different color. It's called Pixel.

2. Resolution refers to the number of dots or pixels in a unit of length of a digital image. For example: An image resolution of 100 dots per inch is called 1 OODPI (Dots Per Inch).

3. In some digital image processing software, each 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 The more common unit), we can know from the impression of traditional photo printing, the finer the particles of the film and photo paper, the finer the image quality that the photo can display.
Since the digital image is composed of pixels, naturally the higher the resolution (ie, the number of pixels per unit length), the better the digital image quality will be. Therefore, it can be imagined that the digital quality of the 300DPI digital image will definitely outperform the 72DPI digital image.

4. Before the image is scanned into a digitized 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 rule of the image to the original size.

6. The print resolution is usually expressed in units of line per unit length (Line Per Inch), and varies depending on the type of print and the type of paper. In general: newspaper: 85 lpi; color magazine: 133, 150 or 175lpi; Art Gallery: 200lpi

7. Generally, when we use snow-copper paper and other surface-smooth paper as printing material, 300 pixels/inch (DPI) or 118 pixels/cm (DPC) resolution will be selected for digital image printing. The resolution can be used to print 150 lines per hour (150 Lines Per Inch).

8. The resolution of digital images used on various types of prints depends on the number of printed screens to which the printed material is applied. If you want a higher quality of the network cable, the resolution of the digital image needs to be increased. Generally, the network cable value can be doubled, which is the resolution value that the digital image should have. If the image needs to be magnified, it must be multiplied by the magnification, as shown in the following formula:

Scanning Image Resolution = Number of Printed Wires x 2 x Magnification

For example, if the number of printed lines is 150 lines, the image must be magnified by 3 times. The scanning resolution must reach 9 OODPI (150 LPIx2x3 times). For another example: When the printing network line is 175 lpi, if the image can be printed by the original ruler, it is better to scan the image with 35 Oppi resolution. If you want to enlarge the image twice in size, you should use a scanning resolution of 70 Oppi.

9. When dealing with Line Art, the resolution of the output device should be used as the scanning resolution. For example, to output 12OOdpi black and white photo paper, it should be 12OOppi scanning resolution. If only 300dpi radioprinter is used for output, then 30Oppi is the scanning resolution.