Digital BW, The Print

More accurately, Roy and people like myself who were prodding him along
weren't able to get particularly clear answers as to how the various intents
- well relcol and perceptual in particular - OUGHT to be applied in the B&W
case.  So Roy had to piecemeal together information from scattered sources.
For example, some may recall the initial difficulty Roy had with clipping
highlights.  We latter "discovered" all input data had to be scaled for
media relativity, ie media white point, a transform in CIE-XYZ.  Roy found
an article by Adobe which described their black point compensation at a very
high level.  Again another scaling in XYZ space.  BPC plugs a gap in the ICC
spec.  So then you've got (media) relative colormetric with BPC.  The
perceptual intent allows a free hand to the profile engineer.  However,
whenever we attempted to ask the question:  "how would you, given the
freedom of the perceptual intent, apply such freedom to a simple B&W
scenario?" we didn't get many, if any, answers.  Roy will correct me if I am
wrong, but he has essentially applied relcol+bpc and slotted it in the
perceptual tags.  It was slotted in the Perceptual tags because the
intention from the beginning was to develop an appropriate perceptual
transform.  In a later iteration that he mentioned in an earlier post, he
filled out the other intent tags with the same transform because of some
uncertainty as to how PS used these others tags when establishing soft
proofs.  Perceptual intent formulae tend to be closely guarded secrets:  the
secret sauce that distinguishes one profiling package from another.
Nonetheless, since none attend to the needs of the B&W photographer (not
using a colour workflow) we would greatly appreciate the expertise that
perhaps someone like David could provide. I think it's fair to say that we
are very happy with the transform currently embedded in a QTR ICC profile,
particularly given that it's affect can be soft proofed, but would like to
find out more about whether or not alternative transforms may be useful or
more "scientifically correct".


> From: <CDTobie@...>
> Reply-To: <DigitalBlackandWhiteThePrint@yahoogroups.com>
> Date: Mon, 27 Feb 2006 10:39:19 EST
> To: <DigitalBlackandWhiteThePrint@yahoogroups.com>
> Subject: Re: [Digital BW] Re: Questions about Using Color Settings and
> Workspace Profiles for Grayscale Printing
> 
> 
> In a message dated 2/27/06 12:57:45 AM, odesmais@... writes:
> 
> 
>> Sorry if I was unclear. QTR is quite well documented, so one knows
>> perceptual is to be used.
>> 
>> What I can't figure out due to limited understanding is WHY perceptual
>> instead of relative is being implemented by Roy.
>> 
>> It's about pure personal understanding...
>> 
>> 
> 
> I would guess because its the most common default. So it would be selected,
> not because its actually related to what the software's doing, intentwise; but
> because its the default intent that is most commonly autoselected, and
> therefore the best choice for single intent functions.
> 
> C. David Tobie
> Product Technology Manager
> ColorVision Business Unit
> Datacolor Inc.
> CDTobie@colorvision.com
> www.colorvision.com
> 
> 
> [Non-text portions of this message have been removed]
> 
> 
> 
> Please visit the Group Homepage to check the Files, and other resources as
> they are often being updated.
> 
> http://groups.yahoo.com/group/DigitalBlackandWhiteThePrint
> 
> If you wish to receive no emails or just a daily digest, or you wish to
> unsubscribe, please edit your Membership preferences by visiting this same
> page.
> 
> Please follow these basic guidelines:
> - As threads develop, trim off excess portions of earlier messages to keep
> them short.
> - Good manners are required at all time. No personal attacks or flames.
> Hostile, aggressive or argumentative users may be removed from the membership
> without notice.
> - Keep your posts and threads related to the group topic of digital B&W
> printing. Users who persistently make off-topic posts may be removed from the
> membership.
> - By posting on this forum you agree to abide by the group rules and
> guidelines, and to abide by the actions and decisions of the group Owner and
> Moderators. See „Group Topic, Rules and Guidelines‰ in the Files section:
> http://groups.yahoo.com/group/DigitalBlackandWhiteThePrint/files/
> 
> BY PARTICIPATING IN AND/OR POSTING MESSAGES TO THE DIGITAL BW, THE PRINT
> YAHOO! GROUP YOU EXPRESSLY UNDERSTAND AND AGREE THAT THE „OWNER‰ AND
> „MODERATORS‰ OF DIGITAL BW, THE PRINT YAHOO GROUP SHALL NOT BE LIABLE TO YOU
> FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, CONSEQUENTIAL OR EXEMPLARY
> DAMAGES, INCLUDING BUT NOT LIMITED TO, DAMAGES FOR LOSS OF PROFITS, GOODWILL,
> USE, DATA OR OTHER INTANGIBLE LOSSES (EVEN IF THE  „OWNER‰ AND „MODERATORS‰ OF
> DIGITAL BW, THE PRINT YAHOO GROUP HAVE BEEN ADVISED OF THE POSSIBILITY OF SUCH
> DAMAGES), RESULTING FROM: (i) THE USE OR THE INABILITY TO USE THE DIGITAL BW,
> THE PRINT YAHOO GROUP; (ii) UNAUTHORIZED ACCESS TO OR ALTERATION OF YOUR
> TRANSMISSIONS OR DATA; (iii) STATEMENTS OR CONDUCT OF ANY THIRD PARTY ON THE
> DIGITAL BW, THE PRINT YAHOO GROUP; OR (iv) ANY OTHER MATTER RELATING TO THE
> DIGITAL BW, THE PRINT YAHOO GROUP.
>  
> Yahoo! Groups Links
> 
> 
> 
>  
> 
> 
>