1968, Alan Kay put forward Dynabook vision _ graphic

1968, Alan Kay puts forward dynabook ideas
"Notebook sized computer loaded with multimedia and can store everything"
Will be a book-like, both portable and interactive functions of the multi-media personal computer, its main specifications are as follows:
1. Easy to carry the size of A4 paper;
2. The resolution of the display must be better than the newspaper text;
3. Must have the function of sound input and easy operation;
4. Must be able to network and make wireless communication
The size of the A4 paper is 210mmx297mm,
When you set the resolution to be 72 pixels per inch, the A4 paper size of the image pixel is 595x842,
When you set the resolution to be 150 pixels per inch, the A4 paper size of the image pixel is 1240x1754,
When you set the resolution to be 300 pixels per inch, the A4 paper size of the image pixel is 2479x3508,
You choose a different resolution, the pixel size of the image also changes.
Of course, don't forget 1 inches = 25.4 millimeters.
Resolution calculation of printing image
1. Digital images processed by computers are also known as "dot Matrix Graphics",
You can imagine a dot-matrix graphic as a combination of many different colors of square color blocks,
And every square color of a different color we call a pixel (Pixel).
2. Resolution (resolution) refers to the number of dots or pixels that a digital image contains in the unit length.
For example: An image resolution of 100 dots per inch is called 1OODPI
(Dots per Inch).
3. In some digital image processing software, each point is called a pixel (Pixel),
So the resolution unit is also called PPI (Pixels per Inch),
Whether it's DPI or PPI (dpi, this is a more common unit),
From the impression of the traditional printing of photographs, we can see that the finer the particles of film and paper are,
The more delicate the quality of the image that can be displayed by the photograph.
Since the digital image is made up of pixels, it is natural that the higher the resolution
(That is, the more pixels the unit length contains), the better the quality of the digital image will be.
Therefore, it is conceivable that the image quality shown by the 300DPI digital image,
Will definitely outperform the 72DPI digital image.
4. Before scanning the images into digitized electronic map files,
The output resolution and image magnification of the printed product must be determined first.
5.[magnification] is the ratio of the image's print ruler to the original size.
6. The resolution of the print is usually in the unit length of the number of lines (line per Inch) as a unit,
Depending on the type of print and the type of paper, in general:
Newspaper: 85lpi
Color magazine: 133, 150 or 175lpi
Art Album: 200lpi
6. Generally when we adopt snow copper paper, such as smooth surface of the paper for printing material, will choose
Resolution of 300pixels/inch (DPI) or 118pixels/cm (DPC)
For the printing of digital images, so that the resolution of the image is used for printing
Can reach the 150 line (Lines per Inch) The number of cable quality.
7. In various types of printed matter, the use of digital image resolution,
Depending on the number of printed lines applied to the printed material.
If you want a higher number of cable quality, the resolution of the digital image needs to increase,
Generally, you can multiply the number of network cable by twice times, which is the resolution value of the digital image.
If the image needs to be magnified, you must multiply the magnification, as shown in the following formula:
Scanning image resolution = printing line number x 2 x magnification
For example: The number of printed network line is 150 lines, the image must be magnified 3 times times,
The scanning resolution must be up to 9OODPI (150lpix2x3 times).
Another example: when the printing line is zoned 175lpi, to be able to print the image in the original ruler,
It is best to scan the image with a 35Oppi resolution.
If you want to enlarge the image twice times the layout of the print, you should use the 70Oppi scanning resolution.
8. When working with black and white lines (line Art), the resolution of the output device should be used as the scanning resolution.
For example, to output 12OOdpi black-and-White paper, 12OOppi should be the scanning resolution.
If the output is only 300dpi, then 30Oppi is the scanning resolution.