[argyllcms] Re: Don't use old measuring devices -- was: Re: Bugfix for Chroma4 in beta 8

On Jan 22, 2008 5:02 PM, Peter Karp <qmailing@xxxxxxxxxxxxxxxx> wrote:
> > On 1/22/08, Peter Karp <qmailing@xxxxxxxxxxxxxxxx> wrote:
>
> > Just a few question since this I am curious man. So you think it's
> > possible to go thru the entire calibration/profiling process with a
> > faulty device and still don't get suspicious high errors?
>
> In a short answer: yes.
>
> But it depends which 'high errors' you mean. When you calibrate a
> display and then "verify" the result with the same device you won't
> find out about the bad behavior of your device by the numbers. If
> measuring a blue color will give you values for a red one and then
> testing the display with the same device will of course still give the
> same wrong readings and will testify that the blue color indeed would
> be red.
>
> If you mean 'high errors' which become visible -- the answer will be:
> it depends. I know this is not the answer one likes to hear and we
> would need to go into more detail if you will detect errors without a
> reference (print for example) or by solely looking at the display, but
> IMO one of the biggest problems is the lack of options to verify if a
> color measuring device gives accurate readings. If you have followed
> some of the discussions on the colorsync list you will have read some
> interesting postings from Tom Lianza explaining a bit that even
> evaluating and comparing lab grade instruments (spectrophotometers in
> that case)is not such a trivial task one might think.
>
> I hope/think that there will be improvements in the area to test a
> device in the next years. Please ask your dealer and the people from
> Datacolor and X-Rite about the accuracy and precision of the
> instruments. Ask them about long-time-stability and how you as an end
> user can verify if the device is still o.k. For the EyeOne Pro you can
> send the device to X-Rite, but for the colorimeters you have no viable
> chance today.
>
> The current available measuring devices (colorimeters for monitors)
> are fairly accurate [whatever that means ;-)] today, but you'll find
> notable differences even between the current _new_ devices, which are
> clearly visible. But at least they are in the same ballpark. Using an
> aged device might be there too, but chances are high you left the
> stadion ;-)
>

Thanks Peter.
Thanks for a nice write-up. I found this quite scary. With this
information I'm glad I have a couple of different devices.
I'm guess a double check can help?


I will be lurking on the colorsync list in the future. It looks like
there are plenty of interesting topics there.

Lars Tore Gustavsen

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