Datacolor SpyderPRINT User Manual page 17

This is the window that opens whenever you're going to measure patches from
target prints. What you're seeing is a grid of color patch "slots" that corresponds
to the physical patches printed in the Target you chose. The grid is labelled in
columns by letter, and in rows by number, to also correspond to the physical
target print. The bold "1" in the lower right, beneath the patches, reminds you that
this is Page 1 in the target. The two popups in the lower right corner of the
window are used to set the measuring mode; and the display mode. In this
example, measuring mode is set to Strip (the other choice is Patch).
The display mode for the window defaults to "Split" (the other choices are "Pure"
and "Measured"). When in Split mode, each patch rectangle is drawn in 2 colors:
the upper left corner of the rectangle is drawn in the "pure" RGB color that exists
for that patch in the target. The "pure" color is the "raw" RGB color that was sent
through the printer driver and which, when the target has been correctly printed,
will have produced an "uncalibrated" color patch for you to measure. So for
example, for the red patch in the target ("full" RGB red of (255, 0, 0)", that's the
pure color displayed for that patch in the window. The lower right corner of each
patch rectangle is drawn in whatever color you've measured into that slot. In this
example, all of the patch rectangles have "white" in the lower right corner
because they're "empty" – none of them are measured yet.