Color separations in Illustrator

When you print artwork professionally, each color is output on a separate printing plate. These plates are inked and printed in alignment to reproduce the final artwork. Understanding color separations can help you prepare files correctly and communicate print requirements more effectively.

Color separations are commonly used in commercial printing for marketing materials, packaging, publications, and other print projects.

What are color separations?

Color separation is the process of dividing artwork into individual color components, each of which is printed on its own plate

For most full-color jobs, artwork is separated into four process colors:

• Cyan
• Magenta
• Yellow
• Black (CMYK)

Each color is printed from a separate plate. When the printed plates align correctly, they reproduce the colors and details in the original artwork.

Artwork can also contain spot colors, which are premixed inks created to match specific color requirements. Each spot color requires its own plate in addition to any process color plates used in the document.

The files or film generated for individual color components are called separations.

Preview color separations

You can preview color separations and overprinting using the Separations Preview panel.

Previewing separations on your monitor lets you preview spot color objects in your document, and check the following:

Rich black: Previewing separations lets you identify areas that will print as rich black, or process black (K) ink mixed with color inks for increased opacity and richer color.

Overprinting: You can preview how blending, transparency, and overprinting will appear in color-separated output. You can also see overprinting effects when you output to a composite printing device.

How Illustrator creates separations

When preparing artwork for print, Illustrator evaluates all color information in the document, including:

• Fills
• Strokes
• Gradients
• Placed images

The application assigns color information to the appropriate process color or spot color plates.

Process colors are distributed across the CMYK plates according to their color values. Spot colors are output as separate plates.

Host-based separations

In a host-based workflow, Illustrator creates the separation data on your computer before sending it to the output device.

Illustrator generates PostScript information for each separation plate and sends that data to the printer or imagesetter.

This workflow provides direct control over separation output and is often used with older printing systems.

In-RIP separations

In an in-RIP workflow, Illustrator sends a single composite PostScript file to the output device. The raster image processor (RIP) creates the color separations during output.

This approach reduces the amount of data generated by Illustrator and can improve processing efficiency. Depending on the RIP, related tasks such as trapping and color management may also be handled during output.

Consult your print service provider to determine which workflow is recommended for your production environment.

Understanding emulsion

If your workflow involves film output, you may encounter specifications related to emulsion direction.

The emulsion is the light-sensitive coating applied to film. Output can be generated with the emulsion facing toward or away from the viewer.

Up (Right Reading): Text reads correctly when the emulsion side faces you.

Down (Right Reading): Text reads correctly when the emulsion side faces away from you.

Paper output typically uses Up (Right Reading), while film output often uses Down (Right Reading). Requirements can vary by print provider, so verify output specifications before generating final separations.

You can identify the emulsion side of film by examining it under bright light. The dull side is the emulsion, and the shiny side is the film base.

Working with your print shop

Before preparing separation output, review requirements with your print provider. They can confirm:

• Preferred separation workflow
• Spot color requirements
• Film and exposure settings
• Device-specific output requirements

For information on generating and previewing separation output, learn how to print color separations and preview color separations.