# OSX\_calibration

**URL:** <https://psychtoolbox.discourse.group/t/osx-calibration/1587>\
**Category:** Uncategorized\
**Created:** [December 17, 2004, 6:01am UTC](https://psychtoolbox.discourse.group/t/osx-calibration/1587 "2004-12-17T06:01:18Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![Allen\_Ingling](https://avatars.discourse-cdn.com/v4/letter/a/a183cd/32.png) [@Allen\_Ingling](https://psychtoolbox.discourse.group/u/Allen_Ingling)\
**Post date:** [December 17, 2004, 6:01am UTC](https://psychtoolbox.discourse.group/t/osx-calibration/1587/1 "2004-12-17T06:01:18Z")

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Hi All,  
  
I notice that the roadmap indicates that   
LoadClut and Screen('Gamma') functions are not likely to be ready until January.   
Just wondering how people are linearising their displays using OSX  
  
  
I have found two commands within the documentation which would appear to be designed   
for this purpose:  
  
Screen('ReadNormalizedGammaTable')  
and   
Screen('LoadNormalizedGammaTable').  
  
  
The latter function (as implemented below) successfully loads my lookup table,   
but produces distorted luminance profiles.  
  
 %load linear CLUT  
 fid = fopen('linearisation\_table','r');   
 linCLUT = fscanf(fid,'%d',[256 3]);  
  
 Screen('LoadNormalizedGammaTable', w, linCLUT/255);   
  
  
I'd be grateful for any suggestions.  
  
  
Regards,  
  
  
John Cass  
Department of Physiology  
University of Sydney