[argyllcms] Re: Measuring spectral transmission of lenses (and filters, too)
- From: edmund ronald <edmundronald@xxxxxxxxx>
- To: argyllcms@xxxxxxxxxxxxx
- Date: Sun, 29 May 2011 01:00:04 +0200
I don't get it; set up some incandescendent lamp on a fairly stable power
supply which you already seem to have; put the i1 spectro in the emissive
reading mode, measure the lamp, measure lamp through lens, import the
spectra into a spreadsheet or use awk and divide; voilà! But you already
know all of this.
On Thu, May 26, 2011 at 4:48 AM, Iliah Borg <ib@xxxxxxxxxxx> wrote:
> Dear Listmembers,
>
> For raw conversion, I need to decide if I'm going to use lens / filters
> (polarizing filters are my primary concern) correction matrices over sensor
> "profiles" or not. To make up my mind I need to take measurements of
> spectral transmissions of different lenses and filters. Instrumentation I
> have is: i1Pro and Spectrolino/SpectroscanT. I'm not sure I can use the lamp
> in SpectroscanT (if you know it is possible please advise so), so I started
> with i1Pro.
>
> From reading argyll/spotread documentation it seems that I can use emission
> mode, measuring separately the light source as a backlit and the light from
> the same source passing through the lens; than calculate the transmission
> dividing the pairs of numbers for each wavelength. As far as I understand no
> ambient light attachment is needed in this case.
>
> Another option would be to use -t flag, however only DTP41T and
> SpectroScanT are listed for this flag (with the option to use Spectroscan
> with a separate backlit light). Does this mode works for i1Pro too? An
> attempt to run it with i1Pro caused no error messages, however the results
> are different from those obtained through spotread with -e flag (might be of
> course because in a quick experiment the lens was not placed to the same
> position).
>
> Any comments and advice would be highly appreciated.
>
> On a side note, running spotread from Argyll CMS 1.3.3 with -p flag
> /projector measurement mode/ (OS X 10.6.7) returned "unsupported for my
> i1Pro.
>
> --
> Iliah Borg
> ib@xxxxxxxxxxx
>
>
>
>
>
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