Originally Posted by
DanK
I can't say anything about the Canon apps. I have printed photos using 4 different Canon printers over the years, but I have never used any of their printing apps. I print directly from Lightroom.
However, even if you print from other software, the printer dialogs that come up--after the first one--are the Canon firmware dialogs for the printer, so I am probably seeing pretty much what you are.
Paper size in the printer dialogs I see has nothing to do with image size. It tells the printer what paper size you have put into the machine. It's to tell the printer what to do--for example, how far the print head can move before it hits the edge of the paper. Separately from the paper size, I set the image size, but I do that in Lightroom, not in the Canon firmware.
At least in the case of the printers I have used in recent years, Canon allows you to set custom paper sizes. I use this when the drop-down menu lacks a standard paper size. For example, for reasons I can't fathom, the drop-down menus for mine don't include 13 x 19, which is one of the standard non-metric sizes, so I set that size via the "custom" option. Likewise, there are two 11 inch standards: 11 x 14, and 11 x 17. (The latter is just a 17 x 22, another standard size, cut in half, which makes it a logical choice for the manufacturers.) If I recall, only one of these shows up on the drop down menu. That is all I use the custom setting for--that is, to accommodate standard paper sizes that don't happen to be listed.
I don't print to any specific aspect ratio; I let the image determine that. As a result, even for a given paper stock, ssay 13 x 19 (the one I use most), I have lots of different image sizes. If you are going to cover the image with a mat, you can ignore this; there will simply be more paper covered by the mat in some cases. I generally trim the paper if I am going to show the print without a mat, because it looks better if the white margin is uniform.