Re: X-Rite Response Concerning Optical Brighteners (Correct?)
Re: X-Rite Response Concerning Optical Brighteners (Correct?)
- Subject: Re: X-Rite Response Concerning Optical Brighteners (Correct?)
- From: Roger Breton <email@hidden>
- Date: Sat, 21 Apr 2007 13:20:13 -0400
Dear Rick,
I am not convinced that they do compensate for OB in all intents but I have
to confess my opinion is not based on any personnal extensive testing but on
many threads I've read over the years on this list. Sorry for the lenghty
quoting.
> I had written a support query to X-Rite concerning a query that had been
> threaded on this list back in March under the subject "Please check this
> conifg for me and give your opinion". I can't reproduce my original query to
> X-Rite as it was sent via a web form.
>
> I had run a test confirming to myself that ProfileMaker only adjusted for
> optical brighteners with perceptual rendering (see below), and have also read
> confirmations of the same on the web (thoughout the ColorBurst RIP support
> forum) and in the ColorSync forum.
>
> Yet X-Rite wrote back with the following response:
>
> --
>> The following solution is copied directly from our on-line knowledgebase. I
>> am certain that it will resolve your issue. We did ask Engineering to
>> address your question as to whether PM5 and Eye-One Match 3.6.1 compensates
>> for optical brighteners in all rendering intents and they assured us that
>> they do compensate for all intents.
>
>> . . . (some basic background information defining the use of optical
>> brighteners deleted) . . .
>
>> Recommendation:
>> A UV cut filter is not needed when using ProfileMaker or Eye-One Match
>> software. The ProfileMaker Professional and the Eye-One Match software can
>> detect and compensate optical brighteners (PM: optionally, i1 Match:
>> automatically).
>
>> A UV cut may be helpful when measuring papers with optical brighteners using
>> other software such as MonacoPROFILER.
> --
>
> I'd love to believe they are right, but I'm not convinced. Can someone
> convince me?
>
> Rick Gordon
>
> ---
>
> On 3/28/07 at 11:51 PM -0700, Rick Gordon wrote in a message entitled
> "Re: Please check this conifg for me and give your opinion":
>
>> A quick test based on setting color samplers in neutral, warm, and cool light
>> areas on the PhotoDisc test image, duplicating the file three times, and
>> converting, using ProfileMaker-generated RGB profiles from the same set of
>> measurements (from an Epson 2200 printing to Heavyweight Matte) as follows,
>> shows:
>>
>> * AbsCol: identical values regardless of optical brightener correction
>>
>> * Perceptual: OB-corrected version has B values 1-3 points higher and R
>> values 0-2 points lower than non-OB-corrected version. (G values remain
>> consistent throughout)
>>
>> So, based on that small test, I'd have to concur with John's conclusion,
>> although it's certainly not clearly spelled out in the ProfileMaker
>> documentation.
Regards,
Roger Breton | Laval, Canada | email@hidden
certified color management enthousiast
http://pages.infinit.net/graxx
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