Use PS to make a canvas that is 70 centimeters long, 6 meters wide, and how big should it be?

First, let me tell you the answer based on the banner you made with red background and white characters (or yellow characters):

First, because it is similar to welcome text or slogans, you only need to Set the resolution to 50 and set the rest according to the actual size.

Second, if it is such a banner, it is not recommended that you use PS to make it. It is best to use CorelDRAW. The file is very small, and the format is universal for making banners. CorelDRAW 9 is highly recommended. Other formats may not be compatible.

If it is a banner with a lot of pictures, it can be divided into outdoor and indoor.

Outdoor: The resolution can be set to 50--100, and the other settings should be based on the actual size

Indoor: The resolution can be set to 120-200, and the other settings should be based on the actual size

(There is no point in setting the file to be too large, because when going to an advertising company to produce, the resolution will basically be lowered. Because the file is too high, the device is prone to problems during transmission, such as crashes, etc.)

If you have any other questions, please leave me a message.