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 in Lightroom.
After completing your edits, go to the Print module.
Now click the Page Setup button. On the lower left of your screen.
The Print Setup dialog appears. Choose your printer and click Properties. This will lanuch the printer properties dialog
1. Click on the Page Setup tab.
2. Verify that "Normal-size" is selected in Page Layout. Borderless custom sizes are not an option.
3. Click on the Page Size drop down menu.
Scroll to the bottom of the paper size listing and choose "Custom..."
Canon sets the maximum paper height to 26.61" on most desktop models. This typically translates into a maximum print length of 25.8".
Canon printers do not remember custom sizes. You will do this process each time you have a new size or print job.
Once you create a custom size, set media type, print quality, and color management click OK to exit the printer properties.
You will be back you will again see the Print Setup dialog. Notice that paper size now says "Custom..." Click OK go exit to Lightroom.
You are now back in the Lightroom print module.
Set the cell width and height to their maximum.
You will normally set margins to their minimum value. Notice that they cannot be set to zero. This is because you are using a custom size and printers have a minimum printable margin.
Once complete, Lightroom should display a preview of your image set properly onto the custom size.
Canon Printable Area Note - The leading and trailing edge margins - the area that cannot be printed - are not even. Canon makes the trailing margin larger to assist with paper handling and to avoid print head strikes. This setting cannot be modified while using custom sizes.
To ensure even margins, make all margins slightly larger to match the trailing edge.