Wednesday, 17 January 2007

Crop Digital Photos In Photoshop To Print Proportions

The popular print sizes for photos have different aspect ratios. The aspect ratio is defined by the proportion of the longer length side of the photo to the shorter. I.e. width to hight in landscape format. Aspect ratios of popular print sizes:

Print Size - Aspect Ratio

6x4 - 3:2 (1.5)

5x7
- 7:5 (1.4)
6x8
- 4:3 (1.3)
8x10
- 5:4 (1.25)
8x12
- 3:2 (1.5)
10x15
- 3:2 (1.5)

Digital cameras produce photos with a 4:3 or 3:2 ratio. E.g. Canon A710ID has a resolution of 3072x2304 pixel (= 4:3 = 1.33) and the Canon 20D has 3504x2336 (= 3:2 = 1.50). If you choose a print size with the same aspect ratio as your camera’s resolution, the entire photo will be printed. If you choose a print size not matching your camera’s resolution, a part of the photo will cropped off.

Better crop your photos yourself before getti
ng prints. That way you can decide yourself which part of the photo you will loose. Select the Crop Tool in Photoshop or Photoshop Elements and enter the width and hight of your print size in the options bar:



Now make the selection in your photo. You will notice that the proportion is constant in relation to the values you have entered. Select the part of the photo you want to print (by moving the selected area) and double-click within the selected area. The photo will be cropped accordingly.


Tips

  • Save the cropped photo under a new name, e.g. name_4x3 (File Menu -> Save As command)
  • Do not enter a number in the resolution field of the options bar when entering the print size proportions on the crop tool. That way the image will not be re-sampled during the crop, i.e. the resolution (dots per inch) will not change

1 comment:

waw said...

Hi Thorsten,
Many thanks for the info, been a great help.
Marea