[argyllcms] Re: [Possible bug in Spyd2.c] Inconsistant readings from Spyder3

  • From: Graeme Gill <graeme@xxxxxxxxxxxxx>
  • To: argyllcms@xxxxxxxxxxxxx
  • Date: Sun, 08 Mar 2009 01:01:30 +1100

howdy555@xxxxxxxxx wrote:
Take a look at the enclosed ResultsFull.txt - the result of leaving
the Spyder3 on screen for about 9 hours :)... Open it in any
spreadsheet and plot the X data - you will notice a "dog's tail" at
the beginning, then, after about 2000 readings, it stabilises.

So it seems to be an internal, instrument warm up, rather
than an externally imposed one ? (This instrument seems to
actually have a temperature sensor in it, although this
doesn't seem to made any use of.)

Reading X   Y   Z
1   0.000000    0.175008    0.124630
2   0.000000    0.176625    0.126857
3   0.000000    0.177723    0.127206
4   0.106032    0.187275    0.159078
5   0.106109    0.187766    0.162659

Now this is interesting!!! Have you used the original integration time
or did you incorporate my "hack" that was aimed at exactly this
problem...

I used the original integration time for these results.

Note that Y and Z values are OK whereas X is often a "trash
read"... I do not think X is set to zero when it is less than 0.100 -
I have managed to see values of about X=0.05 when covering the spyder
by hand (I do not have a monitor dark enough to see blacks of such a
low level). It was "flapping (switching between zero and 0.05) all the
time also the results were very inaccurate (it does not trouble me as
the error on X seems to be more than 0.04... All the results were made
using the increased integration time.

Try running with -D3. You can see the raw sensor values then.

Graeme Gill.

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