Aspect Ratios aren't hard to understand but many people don't think about what they mean and don't worry about them when they buy prints of photographs.|
In photography the aspect ratio is a comparison of the width to the height of an image. If you have a photograph with an aspect ratio of 3x2 that means that for every 3 units wide the image is, it is 2 units tall. The units don't matter. They can be millimeters, inches, feet, miles, whatever. There just has to be 3 on the long side and 2 on the short side.
The problem with different sized prints of photographs is that the "standard" sizes don't all have the same aspect ratios. For example; a 4x6 inch print has a 2x3 aspect ratio, a 5x7 inch print has a 5x7 aspect ratio, an 8x10 inch print has a 4x5 aspect ratio. What this means is that the same digital photograph file (JPEG) can't possibly fit all three print sizes exactly. It might fit one of them exactly but not more than one, unless they have an identical aspect ratio.
To get specific, lets say that you have a JPEG that has a 2x3 aspect ratio. If you want to print a 4x6 inch print, that's no problem. If you double the short side of the image (2) you get 4. If you double the long side of the image (3) you get 6. A perfect match. But what happens if you want an 8x10 inch print? OK, to go from 2 to 8 you multiply by 4. Now, when you multiply the long side (3) by 4 you get 12, not 10. That means to get an 8 inch wide print, that includes the entire image, from a 2x3 aspect ratio digital file, it has to be 8x12 inches. You can make an 8x10 inch print from it but you will have to remove (crop) two inches from the long side to make it fit the 10 inch length. Those two inches can be from the top or bottom of the photograph or a combination of both. If you buy the print from my Zenfolio account the default is to remove equal parts from the top and bottom or left and right of a photograph. That means it will remove 1 inch from each of the long ends of the photograph. However, you can override that and move the crop to wherever you want it to be. If there is more important information at the top of the photograph you can slide the crop box up to include the top and cut off 2 inches from the bottom. Or take 1/2 inch from the top and 1 1/2 inches from the bottom. Or any other combination that adds up to 2 inches.
When you purchase prints through Zenfolio you can click 'Visit Shop' then click 'Best Fit' under Prints. You are then first shown the print sizes which are the best fits for the digital file you want to print. Most of my digital files have a 2x3 aspect ratio. That means you will be first shown print sizes that have the same aspect ratio (2x3). You can purchase other sizes but they will require you to decide what parts of the photograph to keep and which parts to crop out. While there is nothing wrong with cropping photographs, and people have had to do it for centuries, since the beginning of photography. If there is part of the photograph you don't want to crop, you will have to buy a "best fit" size.
If you have other questions about this that aren't answered here please feel free to contact me!