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Author Topic: Can't get luminance down on iMAC  (Read 21133 times)

Craig Brewer

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Can't get luminance down on iMAC
« Reply #20 on: October 18, 2008, 08:43:10 pm »

Quote from: jackbingham
All you need to do is look at current system profile. That tells you the final values of your profile.

OK found it, thanks.

ErikKaffehr

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Can't get luminance down on iMAC
« Reply #21 on: October 24, 2008, 02:55:13 am »

Hi!

A hint is that a DeltaE of 5 is visible. Its pretty much on target. I won't go into DeltaE, especially as there are different formulas for it. The colums are

Target LAB and Measured LAB (L is luminance, a, b are color coordinates). Traget and measured values should be as close as possible. Delta E is the geometric mean of the error for all three coordinates (L, a and .

Be happy!

Erik

Quote from: Craig Brewer
Thanks Mark,

I went ahead and calibrated again just to check my settings. Went for Native White Point, 120 luminance, and gamma of 2.2

With the Getag/MacBeth softwareI have used previously it was really plain what your targets were and how far off you might be. Here are the results below but I have to be honest...I ain't got a clue as to what these numbers mean.

Can someone tell me what this means...am I close, on the money, way off?


ColorEyes Display Validation Log
2008-10-17 20:06:57

Display:   iMac 1
System Profile:   New Profile (2008-10-17 19-59)
Created By:   ColorEyes Display
Creation Date:   2008-10-17 20:06:02

Validation Results:
#   C   M   Y   K   Target L   a   b   Measured L   a   b   DeltaE
1   0   0   0   0   100.000   0.000   0.000   100.000   -0.214   -0.121   0.34
2   0   0   0   0   95.645   0.000   0.000   95.627   -0.257   0.204   0.43
3   0   0   0   0   91.230   0.000   0.000   91.204   -0.160   0.052   0.25
4   0   0   0   0   86.756   0.000   0.000   86.682   -0.010   -0.306   0.31
5   0   0   0   0   82.205   0.000   0.000   82.115   -0.237   -0.007   0.36
6   0   0   0   0   77.577   0.000   0.000   77.404   -0.402   0.034   0.61
7   0   0   0   0   70.664   0.000   0.000   70.863   -0.445   -0.125   0.69
8   0   0   0   0   62.787   0.000   0.000   63.392   -0.404   -0.110   0.79
9   0   0   0   0   54.242   0.000   0.000   55.827   -0.118   -0.043   1.51
10   0   0   0   0   41.121   0.000   0.000   42.555   -0.282   0.162   1.37
11   0   0   0   0   26.966   0.000   0.000   28.635   -0.000   -0.158   1.27
12   0   0   0   0   17.005   0.000   0.000   17.683   0.122   -0.305   0.58
13   0   0   0   0   55.382   83.788   83.550   55.223   83.873   83.393   0.17
14   0   0   0   0   86.420   -76.185   91.313   86.481   -76.055   91.456   0.07
15   0   0   0   0   33.705   51.328   -91.717   33.777   51.581   -91.609   0.17

Maximum DeltaE:   1.51
Average DeltaE:   0.59
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Erik Kaffehr
 

Peter S

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Can't get luminance down on iMAC
« Reply #22 on: December 07, 2008, 01:49:15 pm »

Quote from: jackbingham
Might I also suggest that the guided tour has fairly extensive descriptions of how all the tools work and what they mean.

Hi Jack,

I have followed this discussion with interest having bought an iMac (my first Mac) 2 months ago. I have not been impressed with the screen and having downloaded the ColorEyes demo and used it with a Spyder2 there is a noticeable improvement.  Still not quite how I would really like it even after trying numerous options.  The Apple display gave a luminance around 250.  The LCD Brightness only was much better.

I am however very puzzled by the Profile Verification.  I set Auto-validate after Calibration and was pleased to see average dE  0.32 and Max dE of 0.98.
I re-ran Validate half an hour later having removed and re-connected the Spyder.   The results showed average dE 20.59 and Max dE 53.07.  Images on screen look identical to the eye.

Can you please give me an explanation?  Have I messed up somewhere?

I was unable to find the Measure Color List or the Macbeth Color Checker File.  In the Validate Profile window the drop down only had 2 options Validate calibration and Evaluate display profile.

Kind regards
Peter
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