[argyllcms] Re: Using an i1 to measure FWA content?
- From: Martin Weberg <martin.weberg@xxxxxxxxx>
- To: argyllcms@xxxxxxxxxxxxx
- Date: Tue, 9 Feb 2010 10:57:41 +0100
2010/2/9 Gerhard Fuernkranz <nospam456@xxxxxx>:
> Martin Weberg wrote:
>> The readings are different. See attached.
>>
>
> Martin, I assume, after switching between UV-filtered and non-filtered,
> you always calibrate the instrument against the calibration tile again,
> before taking some readings, do you?
Yes, calibration before each reading.
> Well, if we'd assume that the filtered light does not contain any energy
> below 400nm or 420nm, then basically we would have to discard the
> readings for these wavelengths completely,
That's what I've been thinking. If the UV filter goes in both
directions, which I assume, why do we get reflectance below 400nm? No
UV wavelength's are emitted to the paper and no UV wavelength's
reaches the measurement device.
> I could also imagine that the
> instrument possibly applies some kind of regularization in order to
> avoid completely unfeasible readings (dominated by noise only) at the UV
> wavelengths.
Probably. How would the measured colour be affected by setting those
UV wavelength bands to zero?
Martin Weberg
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