Canon Pixma iP90 User Manual page 32

When printing several images on one page, optimization is usually
applied to each image according to its requirements. However, if the
image data has been manipulated using clipping, rotation or other such
operations, group optimization of all images on that page is
recommended. In such cases, select the Apply Throughout Page
check box.
(6) Photo Noise Reduction
When printing images recorded with your digital cameras, blue skies
may be dappled or dark appearing rough. You can reduce this effect
with the Photo Noise Reduction function. Using this function with
photographs other than those taken with a digital camera may cause
images to be disturbed.