Canon imagePROGRAF GP-4000 - Manual (Page 812)

Media Type Selection does not Match Loaded Media Type
Check 1 Is this paper being used for the first time?
If this is the first time to use the paper, it may not be selected correctly. In the media type selection, manually
select the correct paper type.
Check 2 Is the paper you set genuine paper or recommended paper?
If you want to use a paper that is not in the paper information list, register the media type in the Media
Configuration Tool.
Paper Information List
Media Configuration Tool Guide
Check 3 Is there any unevenness in the gloss and color of the paper surface?
Some media types may not be suitable for paper type estimation. If the paper type is not recognized correctly,
manually select the correct paper in the media type selection.
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