"Page total coverage density" - shows the total page coverage rate in percent. This value corresponds with the 5% ink coverage value usually specified in printer manuals. The result can be presented as the following: all the page is converted to the black-and-white format and ink is evenly distributed on the page; get the page evenly filled with gray color of the specified intensity (from 0% to 100%). "It is equivalent to (5% pages)" - displays the number of standard 5% pages to which your layout sheet is equivalent. That is, when "Page total coverage density" equals 10%, this means the printer will use the amount of ink/toner sufficient to print two pages with the standard 5% coverage density.
"Common coverage": This is the percent of all pixels other than white in the selected area. Example: if the rate is 80%, this means that 80% of the page will be covered with ink and 20% will remain blank.
So "Common Coverage" in this terms is always great then "Page total coverage density" because density is not participate in "Common Coverage"
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