Datacolor User to User Support Group.

Two possible factors here. First, and I hate to bring this up;  
Photoshop's paper white emulation tends to accentuate any  
nonneutrality in papertone to an unreasonable degree. Please note that  
the softproof in Spyder3Elite is actually better about this.

Second, there is indeed a tendancy to use a moderate amount of  
whitener is lots of papers; about a negative unit and a half in b star  
value is typical. Some papers, especially photocopy/laser papers, may  
go way, way over the top when attempting to brighten a dull pulp  
colored paper. Unless you are using a media that specifies unwhitened  
or natural, this is to be expected. A measured neutrality is not  
really what papermakers strive for, they want a subjective impression  
of "pure as the driven snow" which requires a measurable amount of  
brighteners to achieve.

C. D. Tobie
WW Product Technology Mngr.
Digital Imaging & Home Theater
DataColor.com
CDTobie@...

On Jan 11, 2009, at 2:08 PM, "John Arnold" <john.arnold@...>  
wrote:

> --- In colorvision_group@yahoogroups.com, Cdtobie <CDTobie@...> wrote:
>>
>> Your understanding of how to rebuild the profile with edits is
>> correct. But you would adjust the a/b values to the setting where  
>> they
>> gave you the softproof tone you desire, not simply to zero, though in
>> a perfect situation, that would do the trick for neutrality.
>>
>> C. D. Tobie
>> WW Product Technology Mngr.
>> Digital Imaging & Home Theater
>> DataColor.com
>> CDTobie@...
>>
>> On Jan 5, 2009, at 5:55 PM, "John Arnold" <john.arnold@...>
>> wrote:
>>
>>> --- In colorvision_group@yahoogroups.com, cdtobie <CDTobie@>
>>> wrote:
>>>>
>>>>
>>>> ___
>>>> Well, your paper tone is one reason, and your paper whiteners
>>> could be another. Adjust the a*/b* values in the "Ref White" box and
>>> rebuild your profile, to adjust the softproof tint.
>>>> --
>>>
>>> Thanks. I have two questions regarding what you have recommended?
>>>
>>> 1) By adjusting my a*/b* values in the "Ref White" box do you mean
>>> setting them both to zero?
>>>
>>> 2) In order to rebuild a profile, do I just choose the file where
>>> the targets are saved that were originally used to build the profile
>>> and then proceed to the next page where you build the profile? I
>>> assume that's right as I don't know of any other way to call up an
>>> existing profile to tweak it.
>>>
>>> Thanks,
>>>
>>> John
>>>
>
> Hi,
>
> I have been thinking about this post and wanted to revisit. The  
> paper I am using does in
> fact measure on the cyan side of white. a*/b* values are both  
> slightly negative when I
> measure with the spectro and I only get the slight greenish cast  
> when I check the
> "simulate paper white" box in Photoshop's proofing setup menu. So in  
> reality, it appears to
> be correct.
>
> Thinking about this prompted me to ask why when I calibrate the  
> spectro, that the b*
> value is always in the negative -1.32 range. I have noticed in the  
> past that others who
> post to this site also frequently get negative b* values that are in  
> the same range when
> they calibrate. I figure that's not accidental and maybe has  
> something to do with
> compensating for paper whiteners or some such thing. I am curious as  
> slight cast in the
> highlights are often more noticeable than cast elsewhere and I am  
> trying to better
> understand how the product works so that I can correctly compensate  
> for this type of
> thing when tweaking profiles.
>
> Hope the above makes sense.
>
> Thanks,
>
> John
>
>
>
>
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