[Openicc] Drop size calibration

[Alastair M. Robinson]

Hi,

Hal V. Engel wrote:

> I also see lots of DTP41 meters on ebay for reasonable prices 
> although these seem to go for more than the hand held devices like the DTP20 
> and you would likely want to send it back to X-Rite to be recalibrated since 
> any of these on ebay will not be new.

My DTP41 came from eBay.

One thing to watch out for - most instruments come with some kind of 
calibration reference card, against which they must be periodically 
calibrated.  Make sure any instrument you buy comes with the calibration 
reference!  The X-Rite instruments are tied to a specific reference, too 
- the card has the instrument's serial number on.  Whether the 
instrument can be "re-certified" against a replacement reference if the 
original is lost or missing I don't know.

Another point, the DTP41 is a great device for profiling, but it would 
be poor choice for the kind of tests you're doing here, because it's a 
strip-reading device which is very fussy about the size and positioning 
of patches on the sheet, and the contrast between patches.  A hand-held 
device would make more sense here, when you're making a small number of 
measurements.

All the best,
--
Alastair M. Robinson