tiramisu said:(Misspelt on purpose)
12R - 12" x 18" or 3600x5400
S10R - 10" x 15" or 3000x4500
10R - 10" x 12" or 3000x3600
S8R - 8" x 12" or 2400x3600
8R - 8" x 10" or 2400x3000
6R - 6" x 8" or 1800x2400
5R - 5" x 7" or 1500x2100
4R - 6" x 4" or 1800x1200
3R - 5" x 3.5" or 1500x1050
What's the current dimension of your current image? Eg 3008 x 2000?
For printing I never resize my images, I send as RAW/TIFF/JPEG for printing depending on the size I want to blow up to. (Ok, maybe I'm a bit KS, JPEG will do fine for S8R.)
4R = 6:4 (1800 x 1200)
If you do simple maths means 1800 / 300 x 1200 / 300 = 6 x 4. This is how you calculate the minimum size you need to send in for 4R prints.
Any multiples of 300 will work fine as long as it's above 1800 x 1200. Eg: 2100 x 1500 etc etc as they're all in the ratio of 3:2.