Canon EOS-1D X Mark III Advanced User's Manual page 461

3.
Set the options as desired.
Set [Print type], [Date], and [File No.] options.
Print type
Date
File No.
4.
Exit the setting.
Press the <
Next, select [Sel.Image] or [Multiple] to specify the images to be
printed.
Standard Prints one image on one sheet.
Multiple thumbnail images are printed
Index
on one sheet.
Prints both the standard and index
Both
prints.
On
[On] imprints the recorded date of the captured
image.
Off
On
[On] imprints the file number.
Off
> button.
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