Re: DataColor SpyderCube
Re: DataColor SpyderCube
- Subject: Re: DataColor SpyderCube
- From: Andrew Rodney <email@hidden>
- Date: Thu, 19 Mar 2009 07:55:18 -0600
On Mar 18, 2009, at 9:29 PM, Cdtobie wrote:
Well, there is a user's guide on the website that you apparently
missed, which includes a spectral graph that shows the Cube to be
more spectrally neutral than the gray Munsel chips in a
ColorChecker, or a Kodak gray card, or even a WhiBal card, though
the WhiBal comes in second.
I'd prefer to measure it myself as I've done with all other products.
The BableColor Tile measured nearly identically on two samples using
an EyeOne as stated on their site. Maybe yours does too. I'll believe
it when I see it.
You are welcome to white balance on the white face if you prefer,
but it's certainly more foolproof to use the gray, since it avoids
spectral clipping. When unclipped the two produce very similar
results.
For Raw capture, the ideal tone is something close to the 2nd white
(#20) of the Macbeth color checker, certainly with the Adobe Raw
engine. You don't want that so called "18% gray" you call your gray in
your product or you could produce some casts due to where that falls
within the linear capture. In fact, when Thomas Knoll designed the
color profiles in ACR, he sampled this #20 patch under two illuminants
to build them and, should you clip channels, ACR will pop an error.
Further:
"Trying to adjust white balance using a gray that is too dark is not
advised. Since you are working primarily with a linear capture where
white balancing Raw captures, a middle gray is too far down the tone
scale to provide an optimal amount of image data to evaluate. A gray
card that has traditionally been used by photographers in the past
should be avoided because its too dark and gray cards aren't noted for
their neutrality. Third party white balance cards are available whose
spectral neutrality have been tested and found to be particularly
useful when used as a white balance sample point for Camera
Raw." (Page 116 of Real World Camera Raw by Schewe and Fraser).
Lastly, the video might be more useful if you teach the behavior of
the Color Sample Tool which provide 5x5 sample based on the zoom
ratio. Zoom in closer to the target, you're more likely to get an
actual 25 pixel sample using the sample tools or WB tool in LR. In LR,
its 5x5 regardless of zoom.
Andrew Rodney
http://www.digitaldog.net/
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