The other day I was trying out a new printer.
I wanted to print A4 sheets, my pictures were in 4x3 aspect ratio, so I used the crop tool set to a custom 210x297 ratio (A4 is 21 cm x 29,7 cm).
Each time I tried to print, the printer software cropped the pictures again, as if the aspect ratio was not good…
I don’t understand what I am doing wrong. I tried with a smaller format (10x15cm), and the same problem came up.
It’s difficult to visualise your workflow, you haven’t given many details but as @MikeR has suggested it sounds like you haven’t set the scaling correctly in the print dialog.
For borderless printing, the printer needs to offer the respective option. If there is no such option, the borders need to be taken into account.
The Canon printers I used so far needed to be set to print on A4 borderless…through selection in the media options of the printer dialog, which looks like this in my current setup: