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: Marc Levine <email@hidden>
- Date: Fri, 21 Jan 2011 21:21:59 -0500
Hi Roger,
I believe that you now see the (400-700nm) light.
; )
Marc
On Jan 21, 2011, at 9:13 PM, Roger Breton wrote:
> 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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