For Red River Paper greeting cards, scrapbook 12x12 sheets, panorama printing, and other special projects, you need to define a custom paper size in the Canon printer properties. Below are instructions for setting a custom paper size starting in Photoshop Elements.
Canon printers cannot save custom paper size settings. You will need to do this process each time you print a custom paper size.
In Photoshop Elements choose File > Print. The Print dialog will appear. Choose your printer from the Printer drop down menu.
Locate and click Page Setup on the lower left of the Print dialog. This will launch your printer's property dialog.
Locate and click the Page Setup tab. In the Page Size drop down, locate and click on Custom, which will be at the bottom of the list.
If you do not see the "Custom..." option in the Page Size menu, make sure you have "Normal-Size Printing" selected. If borderless printing is selected you will not be able to define a custom size.
Set your custom paper size in this pop-up dialog.
ALWAYS set your smaller sheet dimension to width and larger to height.
Go back to the Main tab and set your media type, quality, and color controls.
Click OK until you are back at the Photoshop Print dialog and preview.
Triple check that Select Paper Size is set to "Custom..." and Select
Print Size is set to "Actual Size...", where the actual size is the custom size you just defined.
Once you verify the above you can proceed and make a print.
Don't see the Custom option in your Page Size drop down?
Make certain that Normal-size and not Borderless is selected in Page Layout. If Borderless is selected you will not see a Custom option in the Page Size drop down menu.
Newer Canon? Some media types don't allow custom sizes?
Some newer Canon printers have rules that block you from using a custom size with certain media types. Why? Who knows!
One example is the Matte Photo Paper media type:
If you have it selected and try to create a custom size, this error appears. Fortunately, how to work around it is listed on the pop-up.
To cancel the safety margin:
Go to the Page Setup tab
Click the Print Options button
In the Print Options dialog, click "Cancel the safety margin regulation for paper size"
You will be able to create / choose a custom paper size, regardless of the media type.
NOTE - The Cancel regulations option is likely to return to its default setting the next time you start a print project.