clone stamp on multiple layers/images at once

This is not exhaustively tested and it will change the appearance somewhat when switching to multichannel – but when re-transfering the edited content the appearance should change back.

If you want to give it a try:

// moves copy of rgb file to multichannel or multichannel file to rgb;
// tries to move layer back to the file and path in the file info of the multichannel copy;
// transparencies are disregarded and will be lost;
// be advised: only useful for clone stamping and healing brush;
// cs5 on macintosh:
// 2011, pfaffenbichler, use it at your own risk;
#target photoshop
if (app.documents.length > 0) {
var mode = app.activeDocument.mode;
switch (mode) {
     case DocumentMode.RGB:
     RGBToMultichannel ();
     break;
     case DocumentMode.MULTICHANNEL:
     multiChannelToRGB ()
     break;
     default:
     alert ("please open an rgb-file with more than one layer or a multichannel-file with a multiple of three channels")
     break;
     };
////////////////////////////////////
}
else {
alert ("please open an rgb-file with more than one layer or a multichannel-file with a multiple of three channels")
};
////////////////////////////////////
////////////////////////////////////
////////////////////////////////////
////// operate on rgb file //////
function RGBToMultichannel () {
var myDocument = app.activeDocument;
// make certain there is more than one pixel layer;
var theLayers = collectPixelLayers (myDocument);
hideOthers (theLayers[0], myDocument);
////////////////////////////////////
if (theLayers.length > 1) {
// make copy and convert;
     var theCopy = myDocument.duplicate("theCopy_"+myDocument.name);
     multiChannel ();
     var theMessage = ["multiChannelAndBack",myDocument.name,myDocument.path, removeSemicolons(theLayers[0].name)];
// remove additional channels;
     while (theCopy.channels.length > 3) {
          theCopy.channels[theCopy.channels.length - 1].remove()
          };
// back to original;
     app.activeDocument = myDocument;
     hideOthers (theLayers[0], myDocument);
// insert other channels;
     for (var m = 1; m < theLayers.length; m++) {
          theMessage.push(removeSemicolons(theLayers.name));
          hideOthers (theLayers, myDocument);
          for (var n = 0; n < 3; n++) {
               var theChannel = myDocument.channels.duplicate(theCopy);
               };
          hideOthers (theLayers, myDocument);
          };
     app.activeDocument = theCopy;
// array of array for spot colors;
     var theColorArray = [[100,0,0,0], [0,100,0,0], [0,0,100,0]];
// make spot channel and set to color;
     for (var q = 1; q < theLayers.length; q++) {
          for (var r = 0; r < 3; r++) {
               var theChannel = theCopy.channels[q * 3 + r];
               theCopy.activeChannels = [theChannel];
               theChannel.kind = ChannelType.SPOTCOLOR;
               changeSpot(theColorArray);
               }
          };
// make channels active;
     var theChannels = new Array;
     for (var o = 0; o < theLayers.length * 3; o++) {
          theChannels.push(theCopy.channels)
          };
     theCopy.activeChannels = theChannels;
// hide all but the first three channels;
     for (var p = 3; p < theLayers.length * 3; p++) {
          theCopy.channels
.visible = false
          };
// insert message in file info;
     infoDescription(theMessage.join(";"));
     }
else {
     alert ("please open an rgb-file with more than one layer")
     };
};
////// operate on multochannel file //////
function multiChannelToRGB () {
var thisDocument = app.activeDocument;
////////////////////////////////////
if (thisDocument.channels.length >= 6 && String(thisDocument.channels.length / 3).indexOf(".") == -1) {
// make copy and change to rgb but don’t color manage;     
     var theCopy = thisDocument.duplicate("theBackCopy");
     modeRGB ();
     dontColorManage();
// get message;
     var theMessage = theCopy.info.caption.split(";");
// set colors;
     var white = new SolidColor;
     white.hsb.hue = 0;
     white.hsb.saturation = 0;
     white.hsb.brightness = 100;
     var black = new SolidColor;
     black.hsb.hue = 0;
     black.hsb.saturation = 0;
     black.hsb.brightness = 0;
// insert other channels;
     for (var m = 1; m < theCopy.channels.length / 3; m++) {
          theCopy.selection.selectAll();
          var theLayer = theCopy.artLayers.add();
          theCopy.activeLayer  = theLayer;
          theCopy.selection.fill(white);
          for (var n = 0; n < 3; n++) {
               theCopy.selection.load(theCopy.channels[m * 3 + n], SelectionType.REPLACE, false);
               theCopy.activeChannels = [theCopy.channels];
               theCopy.selection.fill(black);
               };
          };
     theCopy.activeChannels = [theCopy.channels[0], theCopy.channels[1], theCopy.channels[2]];
     theCopy.selection.deselect();
// look for original file;
          var theOriginal = false;
          for (var p = 0; p < app.documents.length; p++) {
               if (app.documents
.name == theMessage[1] && app.documents
.path == theMessage[2]) {
                    var theOriginal = app.documents
                    }
               };
          if (theOriginal == false && File(theMessage[2]+"/"+theMessage[1]).exists == true) {
               var theOriginal = app.open(File(theMessage[2]+"/"+theMessage[1]))
               };
          app.activeDocument = theCopy;
// rename the layers and try to move them back;
     if (theMessage[0] == "multiChannelAndBack") {
          var count = 3;
          for (var o = theCopy.layers.length - 1; o >= 0; o--) {
               theCopy.layers.name = theMessage[count] + "_edited";
               count++;
               if (theOriginal != false) {
                    theCopy.layers.duplicate(theOriginal, ElementPlacement.PLACEATBEGINNING);
                    }
               };
          };
     if (theOriginal != false) {theCopy.close(SaveOptions.DONOTSAVECHANGES)};
     }
else {
     alert ("please open an multichannel-file with a multiple of three channels")
     };
};
////////////////////////////////////
////////////////////////////////////
////////////////////////////////////
////// function collect all layers //////
function collectPixelLayers (theParent) {
     if (!allLayers) {
          var allLayers = new Array} 
     else {};
     for (var m = theParent.layers.length - 1; m >= 0;m--) {
          var theLayer = theParent.layers;
// apply the function to layersets;
          if (theLayer.typename == "ArtLayer") {
// collect only pixel layers;
               if (theLayer .kind == LayerKind.NORMAL) {
                    theLayer.visible = true;
                    allLayers.push(theLayer)
                    }
               }
          else {
               allLayers = allLayers.concat(collectPixelLayers (theLayer))
// this line includes the layer groups;
//               allLayers.push(theLayer);
               }
          }
     return allLayers
     };
////// function convert to multichannel //////
function multiChannel () {
var idCnvM = charIDToTypeID( "CnvM" );
var desc117 = new ActionDescriptor();
var idT = charIDToTypeID( "T   " );
var idMltC = charIDToTypeID( "MltC" );
desc117.putClass( idT, idMltC );
executeAction( idCnvM, desc117, DialogModes.NO );
};
////// toggle visibility of others //////
function hideOthers (theLayer, myDocument) {
myDocument.activeLayer = theLayer;
theLayer.visible = true;
// =======================================================
var idShw = charIDToTypeID( "Shw " );
    var desc10 = new ActionDescriptor();
    var idnull = charIDToTypeID( "null" );
        var list4 = new ActionList();
            var ref7 = new ActionReference();
            var idLyr = charIDToTypeID( "Lyr " );
            var idOrdn = charIDToTypeID( "Ordn" );
            var idTrgt = charIDToTypeID( "Trgt" );
            ref7.putEnumerated( idLyr, idOrdn, idTrgt );
        list4.putReference( ref7 );
    desc10.putList( idnull, list4 );
    var idTglO = charIDToTypeID( "TglO" );
    desc10.putBoolean( idTglO, true );
executeAction( idShw, desc10, DialogModes.NO );
};
////// description //////
function infoDescription (theString) {
// =======================================================
var idsetd = charIDToTypeID( "setd" );
    var desc2 = new ActionDescriptor();
    var idnull = charIDToTypeID( "null" );
        var ref1 = new ActionReference();
        var idPrpr = charIDToTypeID( "Prpr" );
        var idFlIn = charIDToTypeID( "FlIn" );
        ref1.putProperty( idPrpr, idFlIn );
        var idDcmn = charIDToTypeID( "Dcmn" );
        var idOrdn = charIDToTypeID( "Ordn" );
        var idTrgt = charIDToTypeID( "Trgt" );
        ref1.putEnumerated( idDcmn, idOrdn, idTrgt );
    desc2.putReference( idnull, ref1 );
    var idT = charIDToTypeID( "T   " );
        var desc3 = new ActionDescriptor();
        var idCptn = charIDToTypeID( "Cptn" );
        desc3.putString( idCptn, theString );
    var idFlIn = charIDToTypeID( "FlIn" );
    desc2.putObject( idT, idFlIn, desc3 );
executeAction( idsetd, desc2, DialogModes.NO );
};
////// remove semicolons //////
function removeSemicolons(theString) {
while (theString.indexOf(";") != -1) {theString = theString.replace(";", "_")};
return theString
};
////// change spot channel //////
function changeSpot (theArray) {
// =======================================================
var idsetd = charIDToTypeID( "setd" );
    var desc13 = new ActionDescriptor();
    var idnull = charIDToTypeID( "null" );
        var ref4 = new ActionReference();
        var idChnl = charIDToTypeID( "Chnl" );
        var idOrdn = charIDToTypeID( "Ordn" );
        var idTrgt = charIDToTypeID( "Trgt" );
        ref4.putEnumerated( idChnl, idOrdn, idTrgt );
    desc13.putReference( idnull, ref4 );
    var idT = charIDToTypeID( "T   " );
        var desc14 = new ActionDescriptor();
        var idNm = charIDToTypeID( "Nm  " );
        desc14.putString( idNm, theArray.join("_") );
        var idClr = charIDToTypeID( "Clr " );
            var desc15 = new ActionDescriptor();
            var idCyn = charIDToTypeID( "Cyn " );
            desc15.putDouble( idCyn, theArray[0] );
            var idMgnt = charIDToTypeID( "Mgnt" );
            desc15.putDouble( idMgnt, theArray[1] );
            var idYlw = charIDToTypeID( "Ylw " );
            desc15.putDouble( idYlw, theArray[2] );
            var idBlck = charIDToTypeID( "Blck" );
            desc15.putDouble( idBlck, theArray[3] );
        var idCMYC = charIDToTypeID( "CMYC" );
        desc14.putObject( idClr, idCMYC, desc15 );
        var idOpct = charIDToTypeID( "Opct" );
        var idPrc = charIDToTypeID( "#Prc" );
        desc14.putUnitDouble( idOpct, idPrc, 0 );
    var idSCch = charIDToTypeID( "SCch" );
    desc13.putObject( idT, idSCch, desc14 );
executeAction( idsetd, desc13, DialogModes.NO );
};
////// function collect all layers //////
function modeRGB () {
var idCnvM = charIDToTypeID( "CnvM" );
var desc114 = new ActionDescriptor();
var idT = charIDToTypeID( "T   " );
var idRGBM = charIDToTypeID( "RGBM" );
desc114.putClass( idT, idRGBM );
executeAction( idCnvM, desc114, DialogModes.NO );
};
////// function collect all layers //////
function dontColorManage () {
// =======================================================
var idassignProfile = stringIDToTypeID( "assignProfile" );
    var desc3 = new ActionDescriptor();
    var idnull = charIDToTypeID( "null" );
        var ref2 = new ActionReference();
        var idDcmn = charIDToTypeID( "Dcmn" );
        var idOrdn = charIDToTypeID( "Ordn" );
        var idTrgt = charIDToTypeID( "Trgt" );
        ref2.putEnumerated( idDcmn, idOrdn, idTrgt );
    desc3.putReference( idnull, ref2 );
    var idmanage = stringIDToTypeID( "manage" );
    desc3.putBoolean( idmanage, false );
executeAction( idassignProfile, desc3, DialogModes.NO );
};