What is the right resolution for a 50cm by 70cm poster in adobe photoshop, and right resolution for 800/600?

Question

What is the right resolution for a 50cm by 70cm poster in adobe photoshop, and right resolution for 800/600?

Answer 1

A poster 50 x 70 cm is 19.7 x 27.6 inches.  For you best, most probable, print you will need 300 ppi, 280 might be okay.  The image at 300 ppi needs to be 19.7x300 by 27.6x300 or 5910 x 8280 pixels.  Size you image to these pixel dimension and all will be fine when printed to 50 x 70 cm.

BTW, ppi has absolutely no bearing on file size nor will it change the quality of how it looks on your monitor.  However, if you set out to print at 280 ppi then the image size can be reduced to 5516 x 7728 pixels.  This will be a smaller file size because the dimension of the image are smaller.

I don't understand what you are writing about "right resolution for 800/600."

Answer 2

800/600 pixels? Or 800/600 ppi?

The ideal pixel per inch for your poster should be ranged from 300 ppi/dpi to 350 ppi/dpi. Bigger resolution than that is only wasting your RAM and Disk space without getting any better in final print out.