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Author Topic: Spyder Print and Argyll CMS  (Read 766 times)

Doug Gray

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Re: Spyder Print and Argyll CMS
« Reply #20 on: January 25, 2019, 12:47:19 AM »

https://www.youtube.com/watch?v=ijDsdX-EtZ4
Go to minute 21.

I have no qualms at all with the video but I don't think it addresses what the OP wants to achieve. This is all quite confused due to adaptation so let me propose a scenario that gets that out of the equation.

Take an image that is reasonably in gamut on both screen and printer. Create a print using a normal D50 profile. Call that PrintD50. Now make a print using a profile made with a custom illuminant that's 3500K. Call that Print35C. Make a third print using either the scaled spectral approach outlined or by shifting the RG downward in curves per reply #8. Call that Print35S

Now illuminate PrintD50, Print35C, and Print35S with 3500K.

Take a RAW picture of each of these prints and the monitor which is profiled to D50. Process all adjusting for the same luminance but maintaining identical temperature and g/m offset which are set to match the image of the monitor. Paste them all on a single page. Adaptation and even cognitive effects are no longer a factor. L/I issues with the camera imager is a factor, but small in comparison to the relatively stark differences in color temp.

The monitor will be reasonably close to Print35S but Print35C and PrintD50 will both be quite reddish and much closer to each other than either the monitor or Print35S.

I hope this provides more clarity.

Edited to add:

My perspective on what I1P accomplishes with custom illuminant profiles is that they produce optimal profiles for the illuminant when a person is adaptated to that illuminant.  This is, by far, the most common use. When such a print is displayed under that illuminant, such as in an office under a 2700K, 3500K or 4000K light, the person viewing will normally be adaptated to the office illuminant and the print made with a custom illuminant will look proper and produce better color than one with a standard D50 profile. But it's not a huge effect.

A print made to reflect light such that it appears as if illuminated with D50 in a lower CCT environment will look quite strange and very bluish because the viewer will not be adaptated to D50. This is why I stated that doing something like the OP appears to want is appropriate only for some specialized purpose like creating an illusion or special effect. It's not a good idea for general printing.
« Last Edit: January 25, 2019, 10:27:34 AM by Doug Gray »
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stargazer

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Re: Spyder Print and Argyll CMS
« Reply #21 on: January 26, 2019, 10:09:12 AM »

Thanks for your input to this discussion. It has been very useful.
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