Do PDFs sizes change depending on the program that opens it?

Question

I work for a company designing t-shirts. We get transfers printed by another company. The transfers we received for a recent design were to small, as I'm guessing they were printed portrait instead of landscape. The representative from the company we order prints from is claiming that it isn't their fault and that...

"Sometimes the images we receive are not the size you send. This is due to the different formats of the files and the way our computers convert them."

He says it's our fault because we didn't send the design dimensions to him along with the design. The file sent was a PDF. Am I correct in understanding that a PDF will always open at it's intended size? I thought the size was embedded within the PDF. I'm fairly certain I'm correct, but don't want to basically call him out for it without knowing I'm correct. Do computers really convert PDFs so that they're a completely different size? That would be a terrible way for PDFs to operate, if that's the case.

Answer 1

The size is definitely embedded in PDF, and the purpose of PDF format is to be used as the final document format before printing. My advice is to send a note with desired dimensions, perhaps it's their machine that resizes the picture.