The common unit used to express the resolution of bitmap images is "dpi". Bitmap images, also known as bitmap images or raster images, are composed of individual points called pixels (picture elements); when processing bitmaps, the quality of the output image is determined by the resolution set at the beginning of the processing process. The units used to describe resolution are dpi, lpi, ppi and PPD, among which dpi is a commonly used unit. DPI means "dots per inch" in Chinese. It is a unit of measurement used for dot matrix digital images. It refers to the number of sampled, displayable or output dots per inch of length.
The operating environment of this tutorial: Windows 7 system, Dell G3 computer.
Bitmap images (bitmaps), also known as bitmap images or raster images, are composed of individual points called pixels (picture elements). The dots can be arranged and colored differently to create patterns. When you zoom in on a bitmap, you can see the countless individual squares that make up the entire image. The effect of increasing the size of a bitmap is to enlarge individual pixels, making lines and shapes appear jagged. However, if you view it from a slightly greater distance, the color and shape of the bitmap image appear continuous. Photos taken with a digital camera, pictures scanned by a scanner, and computer screenshots are all bitmaps. The characteristic of bitmap is that it can express color changes and subtle transitions of colors, producing realistic effects. The disadvantage is that it needs to record the position and color value of each pixel when saving, which takes up a large storage space. Commonly used bitmap processing software includes Photoshop (which also includes vector functions), Painter, and the drawing tools that come with Windows systems. Adobe Illustrator is vector graphics software.
When processing bitmaps, the quality of the output image depends on the resolution set at the beginning of the processing process.
The resolution determines the fineness of the details of the bitmap image.
Normally, the higher the resolution of the image, the more pixels it contains, the clearer the image, and the better the printing quality. At the same time, it will also increase the storage space occupied by the files.
The common unit used to express the resolution of bitmap images is "dpi".
DPI (Dots Per Inch) is a unit of measurement for dot matrix digital images, which refers to the number of sampled, displayable or output dots per inch of length.
DPI is a unit of measurement for the resolution of devices such as printers and mice. It is one of the main parameters to measure the printing accuracy of the printer. Generally speaking, the higher the DPI value, the higher the printing accuracy of the printer.
DPI refers to pixels per inch, which is the scanning accuracy. The lower the DPI, the lower the resolution of the scan. Due to the influence of network transmission speed, the pictures used on the web are all 72dpi, but this parameter cannot be used for developing photos, it must be 300dpi or higher 350dpi. For example, if you want to develop a 4*6-inch photo, the scanning accuracy must be 300dpi, then the file size should be (4*300)*(6*300)=1200 pixels*1800 pixels.
The unit type that represents the resolution of the bitmap image:
The units that describe the resolution are: dpi (dots per inch), lpi (line per inch), ppi (pixels per inch) and PPD (PPPixels Per Degree angular resolution, pixels per degree). But only lpi is a scale that describes optical resolution. Although dpi and ppi are also units within the resolution category, their meanings are different from lpi. Moreover, lpi and dpi cannot be converted and can only be estimated based on experience.
In addition, ppi and dpi are often used interchangeably. But there are also differences in the fields they use. From a technical point of view, "pixels" only exist in the field of computer display, while "dots" only appear in the field of printing or printing.
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