Datacolor User to User Support Group.

Hi,

Thanks for getting back.

My problem seems to be that I have difficulty translating the LAB 
values to adjustments for the RGB sliders. This gets compounded by 
changes in one color affect the other colors.  For example I profiled 
Epson Glossy paper with Image Specialists Ink. The original reading 
for the gray patch was  LAB 49.45, 4.10, -0.06 or RGB of 115.6. 
105.8, 108.28. SInce this had a pinkish cast I started reducing the 
cyan/red slider.  After several iterations and a complete re-start I 
wound up with slider adjustments of Cyan/Red +2, Magenta/Green +2, 
Yellow/Blue -4.  This gave measured values of LAB 47.93, 0.26, -0.07 
and RGB 104.7, 104.2 104.4 essentially neutral and confirmed by 
different prints; colors seem to be very close, if not right on.  At 
this point I am happy.

It may not be possible, but maybe the Spyder software could have LAB 
correction sliders as well as the conventional RGB sliders.

Thanks for your help.

Bob Schoner

--- In colorvision_group@yahoogroups.com, CDTobie@... wrote:
>
> 
> In a message dated 5/10/08 5:18:53 PM, rschoner@... writes:
> 
> 
> > So, Can I use the colorimeter to spaot measure and edit in this 
way?
> > If yes, how should I convert the Colorimeter Lab output to RGB so 
I
> > can decide how to adjust the sliders?
> > 
> Learn to speak Lab. It makes clear statements about neutrality 
without an RGB 
> conversion: zero values in a* and b* means neutral; positive a is 
red, and so 
> on around the color wheel.
> 
> >  Should I just try for a neutral
> > gray and assume that the colors will be ok?
> > 
> When you are adjusting it is for the neutrals and near neutrals 
where such 
> tiny variations are visible. So yes, just work on the neutrals. But 
the spectro 
> and software have already tried to produce neutral for you already. 
If you 
> have a printer with at least two gray inks, then printing neutral 
images will be 
> much more precise than it will with printers that mix their grays 
from color 
> inks.
> > 
> > One other question. Is there any way to go directly to the profile
> > editor after launching Spyder3 without rebuilding the profile?
> > 
> Spyder3Print does not edit profiles, so there is no way to "go 
directly 
> there". What it does is adjust build parameters from measurement 
sets, so it 
> requires the measurement set(s) to do this.
> 
> C. David Tobie
> WW Product Technology Manager
> Digital Imaging & Home Theater
> Datacolor Inc.
> CDTobie@...
> www.datacolor.com/spyder3
> 
> 
> 
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