We often talk about what dpi is, what is px,and the relationship between resolution and pixels. Many people still don't know what it is. Today we will take a look at how they convert.

Why is the resolution need to up to 300 when printing?For a web page,72 is enough? Most of these people don't know, so today I will take you to find out.

Open a picture in PhotoShop, after zooming in, you can see that each picture is composed of one pixel (of course, vector graphics doesn’t have this concept), we call these one pixel (px) .

Let's copy a 5x5 grid onto the new artboard and look at the image size. You can see that the image size is 5 pixels wide and 5 pixels high.

So we can see that a small color block is a pixel. 

Pixels/feet is actually the measurement unit of resolution Dots Per Inch, that is, how many pixels are filled per inch. The resolution of pixels can be understood like this:

Pixel (width x height) = width (inch) x  resolution x  height (inch) x resolution

The size and clarity of a picture are determined by the size and resolution.

In other words,at the same size, the larger the resolution, then the larger the picture and the higher the definition. When we design for screens and web pages, etc., the resolution is generally 72 pixels per inch (dpi). When we design for print, it must reach 300 pixels per inch (dpi). But it’s not the only one. These can also be used to set the resolution. If you need to use bitmap software such as PS to design small-size prints such as cards and business cards, please set the resolution as high as possible (such as 600dpi, 800dpi or 1200dpi, if it’s large-format prints like posters, it’s not necessary. Your computer will not be able to bear it, and it will only take up more memory. As we usually do for display racks, using 300dpi is completely clear enough. So please remember that the larger the size of the print, the smaller the resolution setting (for example, a resolution of 40MX40M should be around 10.)

Finally, add the most important point: please confirm enough resolution and size before designing, otherwise it will be useless to enlarge it after the design is completed. If the small picture is enlarged in PS, it will be distorted!