Info on pictures size

Are you looking for the following info on cropping your pictures? The dpi should be 300.

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

Crop first and then resize it.

Assuming you are using Photoshop...use the crop tool and set the measurements to 6" x 4" (or vice vesa) and resolution at 300 pixel/in. In this way, not matter how you pull, the ratio always stays at 3:2, at the same time, it will maintain the 4R print size.

-EnD-