1.1 Bitmaps and Vectors
1.1.1 Bitmap
A bitmap is also called a bitmap, which is an image formed by an infinite number of pixels. Each pixel in a bitmap has a fixed position and color value. Rich in color; true-to-life bitmap images are created by varying the coloring and arrangement of a large number of pixels.
1.1.2 Vectors
Vector graphics are a series of graphics drawn by lines connected by lines. The graphic elements in the vector file are called objects, and each object is an independent entity with properties of shape, size, color and contour.
1.2 Resolution
1.2.1 Debate on image segmentation
Resolution is often expressed in the form of "width x height", which plays a vital role in the display and printing of digital images. Image resolution, screen resolution and output resolution are the three most common resolutions
1.2.2 Screen Resolution
Screen resolution refers to the display resolution, that is, the number of pixels or dots displayed per unit length on the display, and the flux is expressed in "dots per inch". A typical monitor has a resolution of 72dpi or 96dpi. Display resolution depends on the size of the display and its pixel settings. show
When the monitor is displayed, the image pixels are directly converted to display pixels, so that when the pixel resolution is used, the image displayed on the screen is larger than its specified print size.
1.2.3 Output Resolution
The output resolution refers to the print resolution. The number of ink per foot (dpi)j produced by laser printers (including imagesetters, etc.) is the printer resolution. Most desktop laser printers have a resolution of 300dpi to 600dpi, while high-end imagesetters can print at 1200dpi or higher
1.3 Color Mode
1.3.1RGB mode
RGB color is often referred to as the three primary colors, with three colors: red, green, and blue.
1.3.2CMYK mode
When sunlight hits an object, the object absorbs part of the light and reflects the rest, and the reflected light is the color of the object that people see.
According to this subtractive color mode, the CMYK color mode suitable for printing is evolved.
CMYK mode should be used when preparing an image for printing in process colors. Converting an RGB image to CMYK mode produces color separations.
1.3.3 Grayscale Mode
Grayscale mode can use up to 256 grayscales to express images, and the transition of the image is smoother and more delicate. Each pixel of a grayscale image has a value between 0 (black) and 255 (white). Grayscale values can also be expressed as a percentage of black ink coverage (0% equals white, 100% equals black). Images scanned with grayscale scanners are often displayed in grayscale.
1.3.4Lab Mode
Lab mode consists of 3 channels, but not R, G, B channels.
1.4 File Format
1.4.1TIFF mode
The Tagged Image Fule Format (TIFF) is a file format primarily used to store images including photographs and artwork. It was originally developed for PostScript printing by Aldus Corporation in conjunction with Microsoft Corporation. TLFF has become a popular high-bit color image mode along with JPEG and PNG.
1.42 CDR format
The CDR format is CoreIDRAW's proprietary image file format. Since CoreIDRAW is a vector graphics drawing software, the CDR format can record the properties, locations and paging of files.
1.4.3PSD mode
The PSD format is the default format for creating and saving image files in Photoshop.
1.4.4AI format
AI format is a vector graphics format created by Illustratir software. AL format files can be directly opened in software such as Photoshop and CoreIDRAW. When opened in CoreIDRAW, the file is still a vector graphics, and the color and shape of the graphics can be edited.
1.4.5 JPEG format
JPEG is an acronym for the joint photographic experts group (Joint Photographic Experts Group), and the file suffix is named ".jpg" or "jpeg". JPEG itself only describes how to convert an image into a byte data stream, but It is not stated how these bytes are sealed on any particular storage medium.