pour impression 80x120

[Prospero]

une très bonne adresse pour calculer exactement ce que tu cherches

scantips

Tu saisis la résolution de ton appareil, le format de sortie, il calcule le nombre de dpi, etc...

Exemple avec un 12M de pixels sur un 60x90cm :

4288x2848 pixels will print 35.43 x 23.53 inches (900.0 x 597.8 mm)
at a MAXIMUM of 121 pixels per inch (48 pixels per cm)
(Maximum meaning any cropping lowers printing resolution)

4288 pixels / 121 ppi = 35.43 inches
2848 pixels / 121 ppi = 23.53 inches

Sufficient pixels to print at 240 to 300 dpi is reasonable quality for photo-quality.

This 4288 x 2848 pixel image size is 12.21 million pixels, with Aspect Ratio 3:2

The image size in memory is: (see explanation of size and megabytes)
69.879 MB if 48 bit RGB
46.586 MB if 32 bit CMYK
34.939 MB if 24 bit RGB (most common)
23.293 MB if 16 bit GrayScale
11.646 MB if 8 bit GrayScale
1.456 MB if 1 bit Line Art