Mailing Lists: Apple Mailing Lists
 Image of Mac OS face in stamp
Re: Another quote from Roy Berns on metamerism-color inconstancy
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: Another quote from Roy Berns on metamerism-color inconstancy

Terence Wyse schreef: 
On Jun 17, 2010, at 5:56 PM, Marco Ugolini wrote:

The quote DOES mention "a SINGLE SAMPLE viewed under multiple illuminants". So, it's ONE The fact that we are dealing with one single sample/specimen IS the whole point of the color inconstancy concept. 


Just to play devil's advocate then, what is the definition of "single
 sample"?

For example, what if I took a neutral R=G=B image, separated it multiple times using different levels of GCR such that under "D50" they would all appear to be perfectly neutral. I then take take them and either print them on a single press sheet or on a single inkjet proof/print. I take this single sheet/print and look at it under different illuminates(?) and lo-and-behold these different separations printed using the same inks on the same substrate take on
different color casts due to the level of GCR in each image.

Would this be color inconstancy or metameric failure?

Terry

A 100% metameric match if you get the patches equal under one light source. If you bring it then to another light source and they are no longer equal you can call it a metameric failure. The conditions are there. Two or more samples compared under different light sources. That the samples are on one page, printed and using the same inks for all doesn't matter.

If your example doesn't make a metameric match under any light source in the universe you could call it "bad color mixing" instead. Which suggests that the metameric failure could do with an extra rule: the condition that the samples showing the metameric failure should be able to make a metameric match under one light source at least. And I do not mean a pitch black environment. It is very scientific and abstract to put an apple green sample and an stone red sample underneath a fluorescent lamp and declare that a metameric failure but who cares for that observation? It also falls in the categories "color inconstancy" and "bad color mixing" if the goal is to get them equal.


--
Met vriendelijke groeten,      Ernst


Dinkla Gallery Canvas Wrap Actions

|          Dinkla Grafische Techniek         |
|             www.pigment-print.com           |
|             (         unvollendet         )            |
_______________________________________________
Do not post admin requests to the list. They will be ignored.
Colorsync-users mailing list      (email@hidden)
Help/Unsubscribe/Update your Subscription:
This email sent to email@hidden






References: 


 >Re: Another quote from Roy Berns on metamerism-color inconstancy (From: Marco Ugolini <email@hidden>)


 >Re: Another quote from Roy Berns on metamerism-color inconstancy (From: Terence Wyse <email@hidden>)























Visit the Apple Store online or at retail locations.

1-800-MY-APPLE


Contact Apple | Terms of Use | Privacy Policy


Copyright © 2011 Apple Inc. All rights reserved.