The difference between RGB and CMYK

On a monitor that displays images digitally, colors are expressed by overlapping three colors (RGB): red (R), green (G), and blue (B). All the color images displayed on the computer are RGB format data.

 

On the other hand, printing machines used at print shops for full-color printing such as commercial magazines, doujinshi (fanzines), postcards and more, generally use cyan, magenta, yellow, key plate (CMYK) inks for printing fine halftone dots. These halftone dots of each color are then superimposed, thereby expressing various colors.

 

For this reason, data for printing machines must have color data that can be expressed in CMYK.

 

Although RGB data can be color converted into CMYK, since CMYK expresses colors with ink, the range of colors (gamut or color space) that can be expressed compared to RGB, which expresses colors with light, is narrower.

 

Since colors that can not be expressed with CMYK are converted into similar colors, the color tone will change when converting the data from RGB to CMYK.

 

In Clip Studio Paint, the data being edited is always maintained in RGB, and it can be converted from RGB to CMYK to create CMYK data when exporting to a general image format.

 

Setting the CMYK color profile

When creating a new canvas, you can specify the following two color profiles under Color profile in the New dialog.

 

Working profile (Previously Profile for preview):

The color profile to be embedded in canvas previews or when exporting to a generic image format. Please set the CMYK color profile (ICC profile) to the one specified by your print shop's submission guide.

 

 

Embedded profile:

The RGB color profile to be embedded in the canvas. When a CMYK profile is set under Working profile, any RGB profile can be specified in the Embedded profile.

The device (display) profile is set by default and can be used as is.

 

Note: "Japan Color 2001 Coated" is commonly used in Japan.

Also, while "Japan Color 2001 Coated" is commonly used in South Korea and Taiwan, "Coated GRACoL 2006 (ISO 12647-2:2004)" is used in North America, and "Coated FOGRA39 (ISO 12647-2:2004)" is used in Europe and other regions. If your print shop hasn't specified settings, feel free to use any of these.

 

Note: In Clip Studio Paint Ver. 4.2 and earlier, settings are configured after creating the canvas by selecting View > Color profile > Color profile settings.

 

Set or change color profiles later

 

After creating the canvas, if you wish to set the color profile or modify the settings, you can do so by following the steps below.

 

• For single canvas works: Edit menu > Canvas Properties

• For multi-page works (EX): Story menu > Change page settings / Change project settings

 

Check how CMYK looks in the color profile preview

When a color profile is set when creating a new canvas, the preview is automatically displayed according to the set color profile.

 

The preview display shows your working data in RGB, closely matching how it will appear in CMYK when printed. Please note that RGB data is being edited, not actually color converted or corrected.

 

The preview display can be toggled on or off by selecting View > Color profile > Preview.

 

Additionally, in View > Color profile > Preview Settings, it is possible to make fine adjustments in addition to selecting the Profile for preview.

 

All about Color profile preview settings

1. Embedded profile:

Displays the color profile embedded in the canvas (clip file). The Embedded profile cannot be changed here. Please make the changes by selecting Edit menu > Canvas Properties.

 

2. Working profile:

You can specify the color profile you want applied when previewing or exporting to a generic image format.

 

3. Rendering intent:

Specify how to convert colors outside the CMYK gamut when performing color conversion.

You can choose between the four types: Perceptual, Saturation, maintaining Relative Colorimetric and maintaining Absolute Colorimetric.

 

Perceptual

This will convert and balance the whole picture with emphasis on the reproduction of tonal colors.

Color correction during color conversion makes it easier to get closer to the original color.

Saturation

This method preserves brightness by comparing the difference between the brightest parts of the image before and after color conversion. This conversion method prioritizes color vividness over color accuracy.

It is not usually used for color conversion while creating works.

Maintaining Relative Colorimetric

Converts the color to a color tone that is close to the original white point (brightness standard). This is often used when realistic replication is needed.

Maintaining Absolute Colorimetric

Select this when performing "hard proofing" to simulate an offset printing press using a printer or other device to proof the colors.

It is not usually used for color conversion while creating works.

 

4. Library to use:

This can only be selected in a Windows environment. Select a library to be used for the color conversion.

When switching images between apps that support CMYK, there is a possibility that colors might not match if the apps do not use the same library.

 

If Photoshop is also used when handling the data, we recommend using Microsoft ICM as it can be used in Clip Studio Paint and Photoshop with the same settings.

 

5. Tonal Correction:

When this is enabled, tonal corrections can be used when the colors are converted to CMYK.

This option is only available when you select a profile that has “CMYK:” in the “Preview Profile” section.

 

Tone Curve and Level Correction are the two available correction methods.

The set up is the same as each item in the Edit menu > Tonal Correction.

For more information, please browse the Clip Studio Paint User's Guide on Tone curves and Level Correction.

 

6. Range in application of settings:

Set the applicable range of the changed content in the Preview setting.

 

Save on canvas

If the same file has been opened in multiple windows, the settings will be applied to all windows.

Additionally, the settings you choose when saving a file are preserved, and when you reopen the file after saving, those settings will remain intact.

 

Configure only in this window

The changes to the settings will only be applied to the currently active window.

Please select this option if you want to compare the preview’s results of the color conversion and adjustments.

Also, when saving the file, the changed settings will not be embedded.

 

Note: To compare an image before and after Color conversion, display the Navigator palette or open the same file in a new window via Window menu > Canvas > New canvas.

 

Export in CMYK

From the File menu, choose > Export (Single Layer) or, in the case of multi-page works (EX), select Export multiple pages > Batch Export to display the Export Settings dialog, and choose either .jpg (JPEG), .tif (TIFF), .psb (Photoshop Big Document), or .psd (Photoshop Document).

 

Please set the Expression color to CMYK color in the dialog box, and check Embed ICC profile and then save.

 

If you specify a CMYK profile when creating a new canvas or in the Color profile preview, that profile will be embedded.

 

If it is not specified, the profile set under File (Clip Studio Paint menu in non-Windows systems) > Settings > Color conversion > CMYK profile will be embedded.

 

If images are saved in the CMYK format without embedding a profile, there is a possibility that the colors may change when you print or open it in another application.

 

It is convenient to register frequently used settings in the Export Settings dialog as a preset. For more information, see Register settings to presets.

 

Points to consider when handling CMYK data

When editing or modifying your work, be sure to do so using the original RGB data (.clip file).

If an image that has been exported as CMYK (such as .jpg or .psd) is reopened and edited in Clip Studio Paint, there is a possibility that color conversion will occur internally once again, resulting in unintended dullness or deterioration of the colors.

We recommend making adjustments and corrections to colors using the original RGB data (.clip file), and only then exporting to CMYK. This is the safest method to prevent color deterioration.