It usually won’t be distorted. Because 18:13 and 10:15 are different aspect ratios, the printer generally has to do one of three things: fit the whole image with white borders, crop part of the image to fill the paper, or—less commonly—scale/stretch it if odd settings are enabled.

What actually happens depends on the print service or printer settings. Many systems will center the image and crop the excess, often trimming the top and bottom for a landscape image. If you print it yourself, you control that choice.

Best practice is to crop and size the image yourself for the exact print ratio you want before ordering, so you’re not leaving the result to automated lab settings. Also make sure the file has enough resolution for print quality—roughly 150 PPI for prints viewed from farther away, or around 300 PPI for close viewing.