HP 10ps colorimeter
HP 10ps colorimeter
- Subject: HP 10ps colorimeter
- From: neil snape <email@hidden>
- Date: Fri, 23 May 2003 06:28:58 +0200
on 23/05/2003 3:33, Graeme Gill wrote :
>
The problem with the HP10 linearisation system is that it
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only returns relative density readings, and only works with
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the HP test chart. This means that it is internally subtracting
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out the paper color, so it only works with HP papers (they are
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the only papers it knows the density of, to be able to
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subtract out accurately.), and won't mesh well with any
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serious linearisation system which needs to read the
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actual paper density.
Okay that would explain why some third party papers work out well on
calibration and others not as well. It's expecting a certain reflectance and
if that measure falls within it's tolerance it could work.
>
>
The test chart is CMYK, but encoded in such a way that the
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light cyan and light magenta are "extracted" from the
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contone test chart, and screened by an internal mechanism.
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This means that it won't mesh with a print system that
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uses its own light ink separation or screening algorithms.
Yes this is why one has to start the initial calibration on the very first
printout with a high quality paper as the tables are loaded into firmware.
So this must be one of the reasons that third party rip's don't use the
onboard colorimeter.
>
In summary, if you stick to the HP provided papers, inks,
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drivers or RIPs, then it probably does good things.
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As soon as you want to stray outside these boundaries,
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it is (unnecessarily) useless.
Agreed fully. When I first bought the printer I thought , great idea, no
need for hooking up applications, usb or serial comm devices, dongles and
software to linearise. Later to see that none of the third party rip's would
use it leaving it to only the supplied paper and Scanvec rip, which lacks
linearisation control.
For the price and use of HP consumables it's a novel idea.
Neil Snape
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