Hi,

>When applying the picker template, I often get the warning "Patches .... 
>clipped".

Many people has asked about that. Let's try to do some explanation.

Targets does have several patches set to very high amount of chroma/saturation, 
for example, in Wolf Faust targets, columns 8 and 12 have values of a,b in Lab
space, way off neutral. For these patches, most devices (scanners, cameras) are
not capable to capture the full amount of color. 

Take for example B8. This is a red patch with a Lab of about (40, 60, 51). That 
is very saturated! So, since the device is probably unable to take all the red in this 
patch, red channel hit 255. That is, red channel got "saturated" and hence red is 
"clipped" to maximum, which is 255. 

And this is the meaning of that informative messages. You got some patches "clipped" 
as an indication of device being unable to capture the enormous gamut of Wolf target.

This is not bad per se. The profiler does understand and use those patches to build 
gamut hull. In fact, no clipped patches would be an indication of some going wrong,
or a very, very wide gamut. Such big gamut would be not good at all, on smaller the 
device gamut, the better the image quality.


Perhaps I should change the message to "gamut boundary detected" :-)

Regards,
Marti Maria
The little cms project
http://www.littlecms.com
[EMAIL PROTECTED]

----- Original Message ----- 
From: "T E Schmitz" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Saturday, February 07, 2004 9:47 PM
Subject: [Lcms-user] Profiler - patches clipped


Hello,

When applying the picker template, I often get the warning "Patches .... 
clipped".

Under which circumstances do patches get clipped? Very often A13-A19 are 
effected and also column 15, and DMIN, DMAX.
What effect does this have on the profile?

Thank you for your time.
-- 


Best Regards,

Tarlika Elisabeth Schmitz


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