Luminous Landscape Forum
Raw & Post Processing, Printing => Colour Management => Topic started by: l_d_allan on March 04, 2013, 01:54:45 pm
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I've had a Datacolor SpyderCube for a year or so.
Overall, I'm happy with it, but I am not convinced I'm:
- using it correctly
- have reasonable expectations of its capabilities
- getting the most out of it
I didn't get any "hits" from a search for "spydercube".
Have forum members found the SpyderCube useful? Better alternatives available? No better than less expensive alternatives? Primarily for beginners/hobby'ists such as myself? Unsuitable for pros?
And I'd really appreciate tips on "best practice" beyond what the Datacolor tutorial video shows.
My speculation is that it could be helpful with getting flash-balance adjusted with multiple flashes, accurate dynamic range "by the numbers" (or at least standardized), etc.
FWIW: I also have a WhiBal card from a photo club drawing.
- The gray faces on the SpyderCube don't seem to agree that well with the WhiBal in terms of how much color cast is present when using ACR "samplers"
- My speculation is that the WhiBal is probably more accurate.
- Could be manufacturing variation? Or within tolerances?
- I've put a borrowed reflective spectro on the face of each, and gotten more than a minor amount of difference between the two
- I don't recall the specifics, but seems like the WhiBal was more tightly bunched around 70% L* with lower a* and b* Lab values
- The SpyderCube gray faces had lower luminosity L* (no unexpected), but higher a* and b* values for Lab
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- I've put a borrowed reflective spectro on the face of each, and gotten more than a minor amount of difference between the two
- I don't recall the specifics, but seems like the WhiBal was more tightly bunched around 70% L* with lower a* and b* Lab values
- The SpyderCube gray faces had lower luminosity L* (no unexpected), but higher a* and b* values for Lab
I am always curious how neutral patches and surfaces are of calibration gadgets. A spectrometer that reads into UV and exports spectral data to create spectral plots is the minimum condition to test that. Materials like Spectralon that is based on a very pure PTFE (Teflon) is very neutral, has a high reflectance and does not age fast. Plumber's teflon tape on a white core a very cheap alternative, pull some tape off when the roll gets dirty. When cards have to be gray for a better white point measurement I wonder what pigment is used that will not fade in any hue direction. Carbon black is good but a bit warm from the start, if not it will get warm in time.
Next to a neutral patch an extra white or grey patch that has OBA content to indicate whether UV content in light is high or low might be interesting. One could imagine all kinds of metameric matches/failures for different light conditions when a set of them is used. It will be hard to find an OBA that stands time though. A few minerals show fluorescent behaviour but they are not white.
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Met vriendelijke groet, Ernst
http://www.pigment-print.com/spectralplots/spectrumviz_1.htm
December 2012, 500+ inkjet media white spectral plots.