I'm using a Canon ipf6350 with mac OS10.10 Yosemite printing from LR. The printer driver has a check box for "High-Precision Photographs". Is this setting related to platen or printhead height? When printing on canvas should this be left unchecked? I'm concerned about head strikes on edge of canvas (had to replace one printhead due to this I think - using BC Crystalline and read here of others with edge curl problems). The manual is not clear on this - does not seem to refer to meaning of this setting. When printing on paper, how much difference does this setting make? Any guidance appreciated. Thanks.