RE: Measuring "standard IT8.7/4 Random" on iSisXL using ColorPort 2.0
RE: Measuring "standard IT8.7/4 Random" on iSisXL using ColorPort 2.0
- Subject: RE: Measuring "standard IT8.7/4 Random" on iSisXL using ColorPort 2.0
- From: Roger Breton <email@hidden>
- Date: Fri, 21 Jan 2011 21:13:27 -0500
Marc,
Thank's again for this follow-up reply but, correct me if I'm wrong, how can
the white LED provide "UV-cut" measurements : because the illumination only
cover part of the visible spectrum, does not reach into the UV? You know, I
never consider that white LED illumination as "UV-cut". My "classic" model
of UV filtration was the typical X-Rite-provided UV-cut filter, as used on
the DTP41 and DTP70, for example, which I once characterized as blocking
anything below 400nm. It was a sharp cut-off filter. You say that, in the
case of the iSis illumination, since the white LED only provide illumination
up to 400nm, that it can be considered "UV-cut"? Since it physically does
not provide illumination in the part of the spectrum, below 400nm, where
more optical brighteners would be excited?
If that's the case, I guess I have no choice to pay the penalty for letting
the instrument take whatever time required to measure the chart because I
always want the measurement to include UV excitation. Although ... Funny how
an instrument can change one's attitudes...
BTW, I have yet to try your technique for setting up ColorPort to read the
standard IT8.7/4 Random.
Best / Roger
-----Original Message-----
From: Marc Levine [mailto:email@hidden]
Sent: January-21-11 8:18 PM
To: Roger Breton
Cc: email@hidden; 'Breton Roger'
Subject: Re: Measuring "standard IT8.7/4 Random" on iSisXL using ColorPort
2.0
Yes. If UVcut data is good for you (which is what you get from the white
LED), then that would certainly speed things up. It's when you additionally
want the UV portion of the spectrum that you have to pay the time penalty.
Marc
On Jan 21, 2011, at 8:05 PM, Roger Breton wrote:
> But Marc, I have seen some applications drive the iSis using the
> visible spectrum white LED only? And feed that data straight to the
> host applications, for reporting to the user. So, I am curious. Of
> course, that method cuts the measuring time in half.
>
> Thank's for coming to my rescue / Roger
>
> -----Original Message-----
> From: colorsync-users-bounces+graxx=email@hidden
> [mailto:colorsync-users-bounces+graxx=email@hidden] On
> Behalf Of Marc Levine
> Sent: January-21-11 6:02 PM
> To: email@hidden
> Cc: Breton Roger
> Subject: Re: Measuring "standard IT8.7/4 Random" on iSisXL using
> ColorPort
> 2.0
>
> Roger,
> In ColorPort 2, select "Tabloid" as you page size and set the left
> margin to 5.5cm. That should do the trick regarding the chart format.
>
> As far as the iSis speed goes, the iSis makes 2 passes by design. The
> 2 LEDs
> (1 capturing only the visible spectrum and the other capturing only a
> portion of the UV spectrum) cannot be on at the same time. The 2
> spectrums must be captured independently. I believe that the spectrums
> are then mathematically merged in the SDK and then pushed to the
> application that is driving the device.
>
> In any event, there's no way to turn both LEDs on a once. I am fairly
> confident that this was explored, considering that the iSis was
> originally intended to be a market competitor to the DTP70 (before
> X-Rite acquired GMB). If it were possible to turn both LEDs on at once
> - or possibly flash them at high speed to "weave" the measurements
> together - then X-Rite would have done that.
>
> Last note, I find it additionally interesting that not only must the
> LED and visible spectrum components be captured independently, but
> they must also be captured is the same direction of head-travel. You
> might notice that the head sweeps twice before retracting the media to
> take its second set of UV readings. And... if you have 1 row left in
> the chart, the head will always read the visible, return to home, and
> then read the UV. Strange, but important to somebody somewhere.
>
> Whatever the case, the iSis works like it works. The DTP70 used a
> single light source to capture either UV-in or UV-ex measurement. The
> iSis uses 2 light sources, requiring 2 passes if you want UV-in
> (because the measurement is built from 2 pieces of data). Like Steve
> mentioned, the only way to make the iSis go faster would be to scan in
> "UVcut" mode, where measurement from the UV LED is skipped.
>
> Hope this helps,
> Marc
>
>
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