Set gray point - curves

[velv]

Hi,
what i'm trying to do is make an automated color correction.
first it needs to make a merge of all layers, then it needs to use the blur-> average filter. create a new curves adjustment layer and then i'm stuck... it needs to set the grey point using the middle eyedropper in the curves dialog.

this is what i have come up with so far, all by using the scriptlistner.

Ps i'm very new to all this so any help would be greatly appreciated
thank you !

Code: Select all// =======================================================
var idMk = charIDToTypeID( "Mk  " );
    var desc7 = new ActionDescriptor();
    var idnull = charIDToTypeID( "null" );
        var ref3 = new ActionReference();
        var idLyr = charIDToTypeID( "Lyr " );
        ref3.putClass( idLyr );
    desc7.putReference( idnull, ref3 );
    var idUsng = charIDToTypeID( "Usng" );
        var desc8 = new ActionDescriptor();
        var idNm = charIDToTypeID( "Nm  " );
        desc8.putString( idNm, "Dupe" );
    var idLyr = charIDToTypeID( "Lyr " );
    desc7.putObject( idUsng, idLyr, desc8 );
executeAction( idMk, desc7, DialogModes.NO );

// =======================================================
var idMrgV = charIDToTypeID( "MrgV" );
    var desc9 = new ActionDescriptor();
    var idDplc = charIDToTypeID( "Dplc" );
    desc9.putBoolean( idDplc, true );
executeAction( idMrgV, desc9, DialogModes.NO );

// =======================================================
var idAvrg = charIDToTypeID( "Avrg" );
executeAction( idAvrg, undefined, DialogModes.NO );

// =======================================================
var idMk = charIDToTypeID( "Mk  " );
    var desc10 = new ActionDescriptor();
    var idnull = charIDToTypeID( "null" );
        var ref4 = new ActionReference();
        var idAdjL = charIDToTypeID( "AdjL" );
        ref4.putClass( idAdjL );
    desc10.putReference( idnull, ref4 );
    var idUsng = charIDToTypeID( "Usng" );
        var desc11 = new ActionDescriptor();
        var idNm = charIDToTypeID( "Nm  " );
        desc11.putString( idNm, "Correct CC" );
        var idType = charIDToTypeID( "Type" );
            var desc12 = new ActionDescriptor();
            var idpresetKind = stringIDToTypeID( "presetKind" );
            var idpresetKindType = stringIDToTypeID( "presetKindType" );
            var idpresetKindDefault = stringIDToTypeID( "presetKindDefault" );
            desc12.putEnumerated( idpresetKind, idpresetKindType, idpresetKindDefault );
        var idCrvs = charIDToTypeID( "Crvs" );
        desc11.putObject( idType, idCrvs, desc12 );
    var idAdjL = charIDToTypeID( "AdjL" );
    desc10.putObject( idUsng, idAdjL, desc11 );
executeAction( idMk, desc10, DialogModes.NO );

// =======================================================

?? select grey point in curves ??


// =======================================================
var idslct = charIDToTypeID( "slct" );
    var desc27 = new ActionDescriptor();
    var idnull = charIDToTypeID( "null" );
        var ref9 = new ActionReference();
        var idLyr = charIDToTypeID( "Lyr " );
        ref9.putName( idLyr, "Dupe" );
    desc27.putReference( idnull, ref9 );
    var idMkVs = charIDToTypeID( "MkVs" );
    desc27.putBoolean( idMkVs, false );
executeAction( idslct, desc27, DialogModes.NO );

// =======================================================
var idDlt = charIDToTypeID( "Dlt " );
    var desc28 = new ActionDescriptor();
    var idnull = charIDToTypeID( "null" );
        var ref10 = new ActionReference();
        var idLyr = charIDToTypeID( "Lyr " );
        var idOrdn = charIDToTypeID( "Ordn" );
        var idTrgt = charIDToTypeID( "Trgt" );
        ref10.putEnumerated( idLyr, idOrdn, idTrgt );
    desc28.putReference( idnull, ref10 );
executeAction( idDlt, desc28, DialogModes.NO );

[velv]

So there is no way to do this then ?

[Mike Hale]

I had a look at this after your first post. It requires the script to be able to work out the gamma correction for each channel.

That may be possible, however I didn't pursue it after a few test because this type of color correction suffers from subject failure i.e. Santa's red suit will cause this to over correct towards cyan.

[Mike Hale]

I gave this another go and here is what I came up with. The script below expects a 8bit RGB image.
Code: Select allvar doc = activeDocument;
doc.flatten();
var mainLayer = doc.activeLayer;
var filterLayer = mainLayer.duplicate ();
doc.activeLayer = filterLayer;
filterLayer.applyAverage();

var re = RegExp( '[123456789]+' );
var rValue = re.exec( doc.channels[0].histogram.toString() ).index/2;
var gValue = re.exec( doc.channels[1].histogram.toString() ).index/2;
var bValue = re.exec( doc.channels[2].histogram.toString() ).index/2;

var values = [ rValue, gValue, bValue ];
values = values.sort( function( a, b ){ return a < b } );
var targetValue = values[1];

var redGamma = Math.log( ( 255 / rValue ) ) / Math.log( ( 255 / targetValue ) );
var greenGamma = Math.log( ( 255 / gValue ) ) / Math.log( ( 255 / targetValue ) );
var blueGamma = Math.log( ( 255 / bValue ) ) / Math.log( ( 255 / targetValue ) );

// make the levels adjustment layer
var desc = new ActionDescriptor();
var ref = new ActionReference();
      ref.putClass( stringIDToTypeID( "adjustmentLayer" ) );
      desc.putReference( stringIDToTypeID( "null" ), ref );
   var typeDesc = new ActionDescriptor();
      typeDesc.putClass( stringIDToTypeID( "type" ), stringIDToTypeID( "levels" ) );
   desc.putObject( stringIDToTypeID( "using" ), stringIDToTypeID( "adjustmentLayer" ), typeDesc );
executeAction( stringIDToTypeID( "make" ), desc, DialogModes.NO );
//
var idsetd = charIDToTypeID( "setd" );
    var desc7 = new ActionDescriptor();
    var idnull = charIDToTypeID( "null" );
        var ref5 = new ActionReference();
        var idAdjL = charIDToTypeID( "AdjL" );
        var idOrdn = charIDToTypeID( "Ordn" );
        var idTrgt = charIDToTypeID( "Trgt" );
        ref5.putEnumerated( idAdjL, idOrdn, idTrgt );
    desc7.putReference( idnull, ref5 );
    var idT = charIDToTypeID( "T   " );
        var desc8 = new ActionDescriptor();
        var idpresetKind = stringIDToTypeID( "presetKind" );
        var idpresetKindType = stringIDToTypeID( "presetKindType" );
        var idpresetKindCustom = stringIDToTypeID( "presetKindCustom" );
        desc8.putEnumerated( idpresetKind, idpresetKindType, idpresetKindCustom );
        var idAdjs = charIDToTypeID( "Adjs" );
            var list1 = new ActionList();
                var desc9 = new ActionDescriptor();
                var idChnl = charIDToTypeID( "Chnl" );
                    var ref6 = new ActionReference();
                    var idChnl = charIDToTypeID( "Chnl" );
                    var idChnl = charIDToTypeID( "Chnl" );
                    var idRd = charIDToTypeID( "Rd  " );
                    ref6.putEnumerated( idChnl, idChnl, idRd );
                desc9.putReference( idChnl, ref6 );
                var idGmm = charIDToTypeID( "Gmm " );
                desc9.putDouble( idGmm, redGamma );
            var idLvlA = charIDToTypeID( "LvlA" );
            list1.putObject( idLvlA, desc9 );
                var desc10 = new ActionDescriptor();
                var idChnl = charIDToTypeID( "Chnl" );
                    var ref7 = new ActionReference();
                    var idChnl = charIDToTypeID( "Chnl" );
                    var idChnl = charIDToTypeID( "Chnl" );
                    var idGrn = charIDToTypeID( "Grn " );
                    ref7.putEnumerated( idChnl, idChnl, idGrn );
                desc10.putReference( idChnl, ref7 );
                var idGmm = charIDToTypeID( "Gmm " );
                desc10.putDouble( idGmm, greenGamma );
            var idLvlA = charIDToTypeID( "LvlA" );
            list1.putObject( idLvlA, desc10 );
                var desc11 = new ActionDescriptor();
                var idChnl = charIDToTypeID( "Chnl" );
                    var ref8 = new ActionReference();
                    var idChnl = charIDToTypeID( "Chnl" );
                    var idChnl = charIDToTypeID( "Chnl" );
                    var idBl = charIDToTypeID( "Bl  " );
                    ref8.putEnumerated( idChnl, idChnl, idBl );
                desc11.putReference( idChnl, ref8 );
                var idGmm = charIDToTypeID( "Gmm " );
                desc11.putDouble( idGmm, blueGamma );
            var idLvlA = charIDToTypeID( "LvlA" );
            list1.putObject( idLvlA, desc11 );
        desc8.putList( idAdjs, list1 );
    var idLvls = charIDToTypeID( "Lvls" );
    desc7.putObject( idT, idLvls, desc8 );
var desc = executeAction( idsetd, desc7, DialogModes.NO);


It doesn't match the results of doing this in the GUI but it's very close. At least on the 4 test image I used. I suppose that is due to rounding errors or the fact that I choose to use the middle value of the 3 channels as the target value and Adobe uses a different method.

[velv]

Wow, thanks Mike !
thats fantastic.

[Giggetto]

I find this script fantastic
I wish that instead of the level tonal values
a curve level was created
someone can do it.