In the good old days, things were based on a 4x5" neg that could be
printed to 4 x 5" (1/4th the size of a 8x10" photo paper), or 5 x7,
which allowed for two prints per page, or a 8 x 10", 11 x14, etc.

Then the 35 mm image came along which provided for a about a 24mm x 36mm
image or a 1:1.5 aspect ratio.

Aspect ratio has continued to evolve into many categories. On some
digital cameras, it can even be adjusted. Good labs or software should
not skew or compress one dimension to get it to fit. Instead either the
image should allow for borders in one dimension, or crop the image to
lose part of the other dimension. Some will give you the choice.

Skewing the image shouldn't be done unless you request that done.

Art

Robbie wrote:

I hope this question makes some sense. My camera takes pictures at a 1.5
ration ( 3504 X 2336 ). However, when printing to a 13 X 19, the software
allows me to go bordered or borderless (full). Doesn't that cause a skew? I
also see places that will print 36" X 48" for you. Again, a different aspect
ration. The 4X6 seems to be a true ratio, but I am stumped on the more
popular sizes.