Color Measurement
and Analysis
PatchTool COMPARE WINDOW
statistics
The "Stats" tab of a Compare window. The main graph of the above screenshot is a histogram of the differences between reference data and
measurements made on a monitor, with Display-Check, with 1617 samples which correspond to a standard IT8.7/4 target. Please note that the
stats tab can analyze the differences between two measurements files in the same manner. The currently selected Delta parameter is DeltaE*
computed with the CIEDE2000 color difference formula; the statistics can also be performed using the Cyan, Magenta, Yellow, K, R, G, B, x, y, X,
Y, Z, L*, a*, b*, C*, h, or H* Delta parameter. The reference here is a file defined by Idealliance for the SWOP2006 Coated3 color space; this file,
and many others, are provided with PatchTool.
The Cumulative Relative Frequency (CRF), shown in the purple curve, is the sum of all the bin values; the CRF graph corresponds to the Max
error data group values. The 95th percentile is used as a “GO/NO-GO” threshold in many protocols, including the Idealliance proofing
programs for printers and monitors and the G7 Colorspace Pass/Fail Requirements. Because the measurements were done with an IT8.7/4
target, a certification report can be obtained by clicking on the "Cert. report" button (example of a monitor certification report that was
converted to a PDF format). For more information, please consult the PatchTool Help manual in the sections dedicated to Idealliance printer
and monitor proofing certification and to the Conformance to G7 Colorspace Pass/Fail Requirements (see also the AN-3 and AN-4
tutorials on Idealliance certification).