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Known Participant
October 10, 2024
질문

How to convert pantone in photoshop in the way i need (what is my mistake)

  • October 10, 2024
  • 3 답변들
  • 2771 조회

Hi, I have a file, here it is - https://forum.rudtp.ru/resources/p3405.3516/download
I want pantone 3405C to be converted to cmyk as 100-0-100-20, I set this color in ColorPicker, then I go to "merge spot channel" and get color 87-20-100-6 !!!

How so? I set 100-0-100-20, not 87-20-100-6 !!!

What is my mistake?

How can I get the color I need (100-0-100-20) when converting pantone to CMYK?

PS
In Illustrator I see the same situation when converting my picture with pantone to CMYK.....


이 주제는 답변이 닫혔습니다.

3 답변

davescm
Community Expert
Community Expert
October 18, 2024

Hi

You need to go back to basics and understand that in different colour spaces, the same colour is represented by different numeric values. So numeric values mean nothing unless referenced to a specific colour profile. Conversely, if you use the same numeric values in different colour spaces then you will see a different colour.

Changing to a different colour space is not the answer. That should be set to match the particular printing press you are using - there is no generic CMYK profile (or generic RGB profile fo that matter).

 

Lab values are independent of colour space, so if you type the Lab value into the colour picker (as suggested above by Stephen), the CMYK values that represent that colour in your CMYK colour space will be shown.

 

Dave

Known Participant
October 18, 2024

I get exactly the values ​​that I set in Photoshop 2019 and do not get them in Photoshop 2022.
My color settings in both Photoshops are absolutely identical !!!

How do you explain this?

Stephen Marsh
Community Expert
Community Expert
October 21, 2024
quote

I get exactly the values ​​that I set in Photoshop 2019 and do not get them in Photoshop 2022.
My color settings in both Photoshops are absolutely identical !!!

How do you explain this?


By @Gennady36741311vv21

 

Perhaps reset your preferences in v2022 after backing up actions and other presets.

 

Manually changing the alternate colour values of a spot colour channel to CMYK from their original Lab-based colour book values should bypass colour settings when merging the spot channel to a CMYK document.


As a last resort, you could try the following script on a selected spot channel:

 

 

/*
Alternate CMYK Spot Channel Values scriptUI GUI.jsx
v1.0 - 22nd October 2024, Stephen Marsh
https://community.adobe.com/t5/photoshop-ecosystem-discussions/how-to-convert-pantone-in-photoshop-in-the-way-i-need-what-is-my-mistake/td-p/14908470
*/

#target photoshop

// Create the main window
var dlg = new Window("dialog", "Alternate CMYK Spot Channel Values");
dlg.orientation = "column";
dlg.alignChildren = ["fill", "top"];
dlg.preferredSize.width = 300;

// Create main group for CMYK values
var cmykGroup = dlg.add("panel", undefined, "CMYK Values");
cmykGroup.orientation = "column";
cmykGroup.alignChildren = ["left", "top"];
cmykGroup.margins = 20;
cmykGroup.spacing = 12;

// Create grid rows for each CMYK value
// Cyan Row
var cyanRow = cmykGroup.add("group");
cyanRow.orientation = "row";
cyanRow.alignChildren = ["left", "center"];
cyanRow.spacing = 5;
var cyanLabel = cyanRow.add("group");
cyanLabel.preferredSize.width = 60;
cyanLabel.orientation = "row";
cyanLabel.alignChildren = ["left", "center"];
cyanLabel.add("statictext", undefined, "Cyan:");
var cyanInput = cyanRow.add("edittext", undefined, "");
cyanInput.preferredSize.width = 50;

// Magenta Row
var magentaRow = cmykGroup.add("group");
magentaRow.orientation = "row";
magentaRow.alignChildren = ["left", "center"];
magentaRow.spacing = 5;
var magentaLabel = magentaRow.add("group");
magentaLabel.preferredSize.width = 60;
magentaLabel.orientation = "row";
magentaLabel.alignChildren = ["left", "center"];
magentaLabel.add("statictext", undefined, "Magenta:");
var magentaInput = magentaRow.add("edittext", undefined, "");
magentaInput.preferredSize.width = 50;

// Yellow Row
var yellowRow = cmykGroup.add("group");
yellowRow.orientation = "row";
yellowRow.alignChildren = ["left", "center"];
yellowRow.spacing = 5;
var yellowLabel = yellowRow.add("group");
yellowLabel.preferredSize.width = 60;
yellowLabel.orientation = "row";
yellowLabel.alignChildren = ["left", "center"];
yellowLabel.add("statictext", undefined, "Yellow:");
var yellowInput = yellowRow.add("edittext", undefined, "");
yellowInput.preferredSize.width = 50;

// Black Row
var blackRow = cmykGroup.add("group");
blackRow.orientation = "row";
blackRow.alignChildren = ["left", "center"];
blackRow.spacing = 5;
var blackLabel = blackRow.add("group");
blackLabel.preferredSize.width = 60;
blackLabel.orientation = "row";
blackLabel.alignChildren = ["left", "center"];
blackLabel.add("statictext", undefined, "Black:");
var blackInput = blackRow.add("edittext", undefined, "");
blackInput.preferredSize.width = 50;

// Checkbox for merging the spot channel
var mergeCheckbox = dlg.add("checkbox", undefined, "Merge the selected spot channel");

// Create button group
var buttonGroup = dlg.add("group");
buttonGroup.orientation = "row";
buttonGroup.alignChildren = ["right", "center"];
buttonGroup.alignment = ["right", "top"];
var cancelButton = buttonGroup.add("button", undefined, "Cancel");
var okButton = buttonGroup.add("button", undefined, "OK", { name: "ok" });

// Add button click handlers
cancelButton.onClick = function () {
    dlg.close();
};
okButton.onClick = function () {
    try {
        if (!app.documents.length) {
            alert("No active document found.");
            return;
        }
        var activeDoc = app.activeDocument;

        if (!activeDoc.activeChannels.length) {
            alert("No active channel found.");
            return;
        }
        var activeChannel = activeDoc.activeChannels[0];

        if (activeChannel.kind !== ChannelType.SPOTCOLOR) {
            alert("The active channel is NOT a Spot Color channel!");
            return;
        }

        var idset = stringIDToTypeID("set");
        var desc371 = new ActionDescriptor();
        var idnull = stringIDToTypeID("null");
        var ref28 = new ActionReference();
        var idchannel = stringIDToTypeID("channel");
        var idordinal = stringIDToTypeID("ordinal");
        var idtargetEnum = stringIDToTypeID("targetEnum");
        ref28.putEnumerated(idchannel, idordinal, idtargetEnum);
        desc371.putReference(idnull, ref28);
        var idto = stringIDToTypeID("to");
        var desc372 = new ActionDescriptor();
        var idcolor = stringIDToTypeID("color");
        var desc373 = new ActionDescriptor();
        // Use values from input fields
        var idcyan = stringIDToTypeID("cyan");
        desc373.putDouble(idcyan, Number(cyanInput.text));
        var idmagenta = stringIDToTypeID("magenta");
        desc373.putDouble(idmagenta, Number(magentaInput.text));
        var idyellowColor = stringIDToTypeID("yellowColor");
        desc373.putDouble(idyellowColor, Number(yellowInput.text));
        var idblack = stringIDToTypeID("black");
        desc373.putDouble(idblack, Number(blackInput.text));
        var idCMYKColorClass = stringIDToTypeID("CMYKColorClass");
        desc372.putObject(idcolor, idCMYKColorClass, desc373);
        var idspotColorChannel = stringIDToTypeID("spotColorChannel");
        desc371.putObject(idto, idspotColorChannel, desc372);
        executeAction(idset, desc371, DialogModes.NO);

        if (mergeCheckbox.value) {
            executeAction(stringIDToTypeID("mergeSpotChannel"), undefined, DialogModes.NO);
        }

        dlg.close();

    } catch (e) {
        alert("Error updating color: " + e);
    }
};

// Show the window
dlg.show();

 

 

https://prepression.blogspot.com/2017/11/downloading-and-installing-adobe-scripts.html 

Known Participant
October 18, 2024

As a result, I do the conversion in Photoshop 2019, in Photoshop 2022 the conversion does not work correctly

Stephen Marsh
Community Expert
Community Expert
October 10, 2024

The spot colour is based on a Lab model colour book:

 

 

Conversions use colour management (Edit > Colour Settings), in this case your working CMYK profile, rendering intent etc.

 

Press the "Picker" button to change from the default Lab colour build and type in your required CMYK values:

 

Then when you merge your spot channel to CMYK in Photoshop you will get the overridden value:

 

Known Participant
October 11, 2024

Hello, sorry, but I didn't understand ANYTHING that I should do in the Edit > Colour Settings menu

I have it like this -

Conrad_C
Community Expert
Community Expert
October 11, 2024

Based on your picture, the way a color is converted to CMYK is based on the profile U.S. Web Coated (SWOP) v2, the one selected under Working Space, CMYK.

 

If you aren’t happy with the CMYK values resulting from a conversion, you probably need to select a different CMYK profile. Ideally, you should select a CMYK profile representing the exact printing conditions that your job is targeting (the press, paper, and ink setup that will be used by the printing company to print your job).

 

For example, different CMYK profiles will apply different total ink limits or different black generation, and those will affect how color values are distributed across the CMYK ink channels.