RGB to LAB values via new solidcolor inaccurate?

Participant ,
Jun 01, 2021 Jun 01, 2021

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I've been trying to find a way of automating the sampling of an average color without duplicating a layer and using the filter average command. I work in AdobeRGB and prefer to read LAB numbers for color correction. However what i am finding is that the RGB to LAB conversion of numbers using a solidcolor object produces inaccurate numbers, is there function out there to convert adobeRGB to Lab numbers accurately???

i.e. 

 

RGB: 73.5023530022085 45.439188788593 39.9453177108809

 

outputs these numbers....

L*ab: 22.1099853515625,12.1768493652344,8.62826538085938

 

   sColor = new SolidColor();
red = getMean (0)
green = getMean (1)
blue = getMean (2)

sColor.rgb.red = red
 sColor.rgb.blue = blue
 sColor.rgb.green = green
$.writeln('RGB: '+ red +" "+ green + " "+ blue)

var labValues = rgbToLab(red, green, blue);

$.writeln('L*ab: '+ labValues)
copyTextToClipboard (desc)
alert( desc)


//debugger
function getMean(chanNo){

var histo = activeDocument.channels[chanNo].histogram
var mean = 0;  
var total = 0;  
for (var n = 0; n < histo.length; n++) {  
total = total + histo[n];  
};  
for (var m = 0; m < histo.length; m++) {  
var thisValue = histo[m];  
mean = mean + (m * thisValue / total);  
}; 
return mean}

function copyTextToClipboard( txt )
{
    const keyTextData         = app.charIDToTypeID('TxtD');
    const ktextToClipboardStr = app.stringIDToTypeID( "textToClipboard" );

    var textStrDesc = new ActionDescriptor();

    textStrDesc.putString( keyTextData, txt );
    executeAction( ktextToClipboardStr, textStrDesc, DialogModes.NO );
}


function rgbToLab(red, green, blue) {
  var color = new SolidColor;

  color.rgb.red = red;
  color.rgb.green = green;
  color.rgb.blue = blue;

  return [
    color.lab.l,
    color.lab.a,
    color.lab.b
  ]
}

The base of the code was brilliantly written by @c.pfaffenbichler 

on this post click here 

 

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Actions and scripting

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correct answers 1 Correct Answer

Adobe Community Professional , Jun 01, 2021 Jun 01, 2021
Is Adobe RGB also your RGB Working Space? 

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Adobe Community Professional ,
Jun 01, 2021 Jun 01, 2021

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Is Adobe RGB also your RGB Working Space? 

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Participant ,
Jun 01, 2021 Jun 01, 2021

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Ahh bingo! moved to new version and forgot to update color settings. 

 

new result 

 

RGB: 64.6131759199016 34.4235433383937 26.7300612665365

L*ab: 17.12646484375,19.5230407714844,15.9044189453125

 

Is there a simple way to have this constantly refresh as a mini info pallet, i have never delved into modeless dialogs before, so still on simple scriptUI, and from what i read modeless dialogs quite buggy in scriptUI

 

 

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Adobe Community Professional ,
Jun 01, 2021 Jun 01, 2021

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Sorry, I haven’t familiarized myself with Adobe UXP, either. 

Maybe someone else has some insight.

 

If you want to check out UXP maybe start over on 

https://www.davidebarranca.com/development/adobe-uxp-things-you-need-to-know

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Participant ,
Jun 01, 2021 Jun 01, 2021

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having a look at his videos at the moment, will come back when ive developed something 

 

many thanks for your help

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Adobe Community Professional ,
Jun 01, 2021 Jun 01, 2021

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Why is the rgbToLab() function needed

var labValues = rgbToLab(red, green, blue);

when all lab values are already in the SolidColor object?

var labValues = [sColor.lab.l, sColor.lab.a, sColor.lab.b];

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Participant ,
Jun 04, 2021 Jun 04, 2021

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to be honest before i posted here i was trying all sorts as i couldnt work out why the lab numbers were off. I know the function is not needed. 

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