[argyllcms] Re: Calibrate a HCFR hardware

On dimanche 13 janvier 2008, Gerhard Fuernkranz wrote:

> I guess that the CRT/LCD switch could have other side effects too, like
> syncing to the display's refresh rate (CRT) or omitting the
> synchronization (LCD), and not just to select one of two different
> calibration sets? Graeme, can you please tell, how this is implemented?
> Btw, does the HCFR instrument actually sync to the dispay's refresh rate
> too?

I don't think so, as its main goal is to calibrate projectors (LCD, DLP, 
TT)...

> > You will always get the best possible calibration for a particular
> > display if calibrated using that display type.
>
> ...where limiting the "display types" to only two classes "CRT" and
> "LCD" is already a significant trade-off, which may be still reasonable
> for the various monitor colorimeters (like DTP94, i1 display, Spyder,
> etc.), but which may not be reasonable for the sensors of the HCFR
> instrument, whose spectral responses are far-off colorimetric (see
> http://tinyurl.com/2s5fpo). These sensors may possibly rather require an
> individual calibration for each different display or projector model (or
> even for each individual display device), and not just a distinction
> between "CRT" and "LCD".

What do you mean by "spectral responses are far-off colorimetric"? My 
english is limited :o/

> Maybe dispcal and friends should support instrument specific options,
> which are transparently passed through to the driver and interpreted
> only by the driver? (and for the HCFR driver, a file with individual
> calibration data to use could be such an option).

Yes, it could be nice, especially if it has to be calibrated for each 
device.

> Btw (maybe a little bit OT), when I look at the TCS230 datasheet then
> I'm wondering, whether the HCFR instrument is equipped with an IR filter
> in front of the sensor chips? Otherwise the presence of IR may
> significantly tamper the readings, since all four photo diodes have a
> significant sensitivity at IR wavelengths up to 1100nm (IMO colorimeter
> sensors should not respond to radiation outside the human visible
> spectral band).

There is no IR filter in front of the sensors. I'll suggest that to the 
HCFR team. Do you know where such filters can be found? I  could make a 
test...

-- 
   Frédéric

   http://www.gbiloba.org

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