[argyllcms] Re: Best way to proceed?

On 2008 Jun 1, at 1:58 PM, Klaus Karcher wrote:


Ben Goren wrote:

On 2008 Jun 1, at 3:13 AM, Klaus Karcher wrote:
You can also compare wood measurements taken in close proximity to get a sense of the variances.
I tried that this morning, too. Even a millimeter made a significant difference, especially on oak. Indeed, the variation in sample location is almost enough for different woods to have an overlapping range of Lab values....
Ok -- I think there's nothing else for it but to take a large number of measurements for each kind of wood and average them to get an indication for the "mean" color. As the lightness varies very much with the angle, the a/b coordinates are more meaningful. You can also draw the a/b values of all your readings in a scatterplot and look for marked-off "clouds" for different kinds of wood.
I don't think I'll need to do that at this point, but it'll be the first thing I try if I'm still not happy. I'm especially thinking of Photoshop's select color tool to help identify the centers of those ``clouds.''
BTW: the i1 uses 45/0° geometry (illumination at 45 degrees to the sample's normal and measurement on the sample's normal). Even though the illumination should be approximately circular, it's a good idea to rotate the sample or measurement device amongst the measurements to get better averages. 

Sounds like 3-4 samples per location, if I go that route. Thanks!

Cheers,

b&

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