[Openicc] Drop size calibration

[Hal V. Engel]

On Saturday 02 February 2008 05:50:27 Lars Tore Gustavsen wrote:
> On 2/2/08, Robert Krawitz > wrote:
> > The basic way I would do it in both cases would be to print a linear
> > sweep and try to find a best fit constant that would relate the two
> > curves, or at least the lower part of the curves before dot
> > gain/saturation issues started to come into play (particularly for
> > variable drops).
> >
> > Maybe I really do need a spectrometer...
>
> If so, there is a new rebate going on in US if you live there.
> http://xritephoto.com/html/i1Photo_LT_Rebate_Cert3.pdf
>
> Relatives in US picked up mine up last summer with an similar  rebate
> from this ebay seller:
> http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=150211241322
> In the ends it was around $500. In Norway a colorimeter from xrite are
> more than that.

One other possibility is to look for a discontinued but new device on ebay.  I 
got my DTP20 uv on ebay for $220.  This device was new old stock that was 
being purged from inventory.  So it includes the one year warranty from 
X-Rite.  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.   However they are built like tanks and 
are generally well cared for since they were very expensive, approx. $2500, 
when new.

I occasionally see re-branded EyeOne Pros on ebay as well.  A few weeks ago 
there was an EyeOne Pro that had HP labeling.  It was in unused condition and 
included a bunch of accessories and software and sold for $153.

My point is that if you shop carefully you can get a very nice device for a 
resonable amount.

>
> > Hal writes
> >    In addition I don't know how much variation there is from printer
> >    to printer.  That is some of the problems I was seeing in the
> >    curves of my printer may not show up in your R2400 or the one
> >    Robert has.  Perhaps you could run a set of test measurements using
> >    the same settings I did and drop those into the spreadsheet.  If
> >    the curves look like mine then this is likely not something
> >    specific to my printer.
> >
> > In this particular case I'm willing to all but guarantee that you'll
> > get very similar results.
>
> I can always print a sample, but since I don't have the Ilford paper
> it will takes a while.

I don't think that it is necessary to use the same exact paper since the 
issues that were apparent in the plots where fairly large.  I suspect that 
they would show up on just about any glossy photo quality paper.  But it may 
not be worth doing since Robert believes that my printer is likely fairly 
typical. 

Hal