Tri-Color Digital Imaging Services
Aspect Ratio:
When enlarging or reducing the size of an image, to avoid the need to crop the image, you must maintain the aspect ratio. The aspect ratio of an image can be found by dividing the length of one side, by the length of the other side. One aspect ratio of an 8X10 print is .8, that is 8 divided by 10. Another is 1.25 or 10 divided by 8. The "correct" one to use depends one what you're trying to find.
For example, say you have a photo that is 8x10, and you want to enlarge it to "something" by 20. To find the "something" of your photo, while preserving the aspect ratio (nothing gets cropped), you do the following calculation:
height = 8 / 10 x 20 height = 16
You know two sides, 8" and 10". We'll call 8 the short side and 10 the long side.
Now you have to decide what new size one of the sides is going to become. Let's say the new long side is going to be 20". The calculation above gives you an answer of 16" for the new short side.
What if you know what you want the new short side to be, but need to figure out what the new long side should be? It's easy, use the same equation, but switch the 8 and the 10, and plug in the 16.
height = 10 / 8 x 16 height = 20
Instructions: Fill in both values on the left side of the equation with your starting measurments, then fill in one of the two values on the right side. To find the missing measurement click "calculate."