Home Products Download Order Contacts


Subject: Re: ACR Calibration

After Raw processing, run a moderate Gaussian blur to average noise. Then,
measure & calculate the difference to Bruce’s chart, respectively, in
terms of deltaHSB-hue and deltaHSB-saturation for every single color patch.
Take care to have everything in the same working space.

Would you like to support your proposal by adding the results of this test?


I've just run a modified checker script that Rags provided. I have results for three options:

1. ACR defaults across the board.
2. My manual calibration
3. Your suggested settings (ACR defaults with exposure set to -1)

There are quite a few numbers to deal with but at first glance option 3 has produced the strangest results (worst saturation green, delta -6.1%, worst luminescence yellow, delta -29.91%).

This compares with respective deltas for option 1 with green being -4.82% and the worst luminescence being blue with delta -9.43%.

Option 2 produced worst saturation red, delta -5.34% and worst luminescence red delta +2.85%.

Key indicators are the sum of all deviations (ignoring +/-) as well as
the number of patches which deviate by 5 steps or more; the troublemakers.

Interestingly, option 1 & 3 produced delta RGB for many patches that
far exceeded the deviation of 5 levels. This was greatly amplified for option 3. Option 2 produced only red, green, "moderate red" and "orange yellow" patches that have a slighly greater deviation than 5 (+10 for the B value in the red patch being the most flagrant offender but others only in exceedeance by a couple of levels). All other patches in option 2 are generally + or - 3 on average, far better than the default options.

Perhaps Rags (or you) can let me know which addtional numbers may be of importance from the resulting charts. There are values for Delta RGB, Image HSB and Delta HSB along with summary averages for all, neutral, colors, rgb and cmy values.

But I notice that the summary average Delta H and S values for "colors only" are virtually identical for all three options whereas the B values are significantly different (highest values for option 3, intermediate for option 1 and drastically lower for option 2).



View All Messages in adobe.photoshop.camera.raw

ACR Calibration =>


Copyright © 2006 WatermarkFactory.com. All Rights Reserved.