Impression: For a print job, an impression is the passage of the entire
side of a sheet by the marker, whether or not any marks are made and
independent of the number of passes that the side makes past the marker.
Thus a four pass color process counts as a single impression, as does
highlight color. Impression counters count all kinds: monochrome,
highlight color, and full process color, while full color counters only
count full color impressions, and high light color counters only count high
light color impressions.
One-sided processing involves one impression per sheet. Two-sided
processing involves two impressions per sheet. If a two-sided document has
an odd number of pages, the last sheet still counts as two impressions, if
that sheet makes two passes through the marker or the marker marks on both
sides of a sheet in a single pass. Two-up printing is the placement of two
logical pages on one side of a sheet and so is still a single impression.
See "page" and "sheet".
NOTE - Since impressions include blank sides, it is suggested that
accounting application implementers consider charging for sheets, rather
than impressions, possibly using the value of the sides attribute to select
different charges for one-sided versus two-sided printing, since some users
may think that impressions don't include blank sides.
So I think our consensus is holding here.
Tom
At 08:41 01/05/1998 PST, Harry Lewis wrote:
>We discussed this at length in LA. You may recall, I was the main
proponent of
>accurate accounting (i.e. not counting blank impressions). In LA it was
>established, however, that many, many print controllers would be unable to
>discern a blank impression because the "page eject" command from whatever PDL
>is in use is still invoked. We also agreed that sheet based accounting is
more
>pragmatic except in the case of very high cost marker supplies.
>
>At and/or following LA, we even went to great length to come up with a
>clarified definition of an impression being a sheet side traversing the
marker
>path - whether or not marks were made. We had to do this to prevent counting
>two impressions for every sheet of a simplex job.
>
>Even though I came out the shoot arguing for optimum accountability, I was
>convinced in LA and remain convinced that the compromise described above is a
>good one. I recall discussing an additional (optional) attribute for
"number of
>blank impressions" to accommodate devices that ARE able to detect and account
>for blanks, but don't remember if this has been
>included.
>
>I recommend we remain with these decisions.
>
>Harry Lewis - IBM Printing Systems
>
>
>
>
>jmp-owner@pwg.org on 12/17/97 11:54:27 AM
>Please respond to jmp-owner@pwg.org @ internet
>To: jmp@pwg.org @ internet
>cc: szilles@Adobe.COM @ internet, ipp@pwg.org @ internet
>Subject: JMP> URGENT: Should impressions include blank last page back
>
>
>At the JMP meeting on 12/5, we agreed that the definitions of
>impressions would count the number of times a media side goes past
>the marker, even if there are no marks made.
>
>I think we agreed to that, becasue impressions is supposed to count
>after the sheet is stacked, so that the sheet counter doesn't know whether
>the back side of the last page (documents with an odd number of pages),
>was marked or not, so we said that it SHALL count.
>
>Howver, for an accounting application, the customers may get pretty
>unhappy with having to pay for the final side they didn't use, as
>Angelo points out, when their document has an odd number of pages.
>
>URGENT: I NEED FEEDBACK FROM THE JMP LIST BY THURSDAY 12/18 EVENING.
>HEARING NO OBJECTIONS I'M GOING FORWARD WITH THE FOLLOWING:
>
>So how about RECOMMENDING (but not requiring) that the number of impressions
>for two-sided printing not include counting both sides of sheets marked on
>only one side. It may be that the interpreter has to be involved in
>counting impressions, rather than the sheet counter in the stacker or maybe
>the implementation only worries about the last sheet and so there is just
>an internal status bit that says whether a document has an odd number or an
>even number of sides in order to know whether to count the last sheet as 1
>or 2 impressions.
>
>I suggest changing the sentence in the definition of impression:
>
>If a two-sided document has an odd number of pages, the last sheet still
>counts as two impressions, if that sheet makes two passes through the
>marker or the marker marks on both sides of a sheet in a single pass.
>
>to:
>
>If a two-sided document has some sheets that only have marks on one side
>(such as on the last sheet of a document with an odd-number of
>impressions), those sheets SHOULD count as one impression, instead of two,
>even if that sheet makes two passes through the marker.
>
>BTW, the current definition of "impression" in the IPP Model is:
>
>12.2.15 impressions
>
>An "impression" is the image (possibly many print-stream pages in different
>configurations) imposed onto a single media page.
>
>So it seems that the IPP Job Model is in agreement with the following
>recommendation for the Job Mon MIB:
>
>
>The full definition of the term impressions (as sent yesterday) is
>for the Job Monitoring MIB:
>
>Impression: For a print job, an impression is the passage of the entire
>side of a sheet by the marker, whether or not any marks are made and
>independent of the number of passes that the side makes past the marker
>
>