Special ink data is defined as spot colors in design software such as Adobe Illustrator. This article will guide you through the process of creating spot colors in these applications for later use in CalderaRIP.

The information below is a summary of the official Adobe documentation. If you want to know more details, please refer to their site directly.

Step 1: Create the spot color

1. Open your design software (Adobe Illustrator in this example).
2. (Optional) Ensure that the Swatches panel is visible. If it is not displayed, go to the top menu, click on "Window," and then select "Swatches" from the dropdown menu. This panel allows you to manage and apply colors, including spot colors, in your design.
3. Create a new swatch using the New Swatch icon at the bottom:
   
   

     Warning

   The following two steps are crucial, as they enable CalderaRIP to automatically assign your spot color to the white ink channel!

4. Change the Swatch Name to the name of your spot color ("White" in this example).

     Good to know

   This process is not limited to white ink; it also applies to other special inks such as fluorescent, primer, varnish, gloss, transparent, silver, and metallic. In these cases, you only have to name the spot color(s) accordingly.

5. Change the Color Type to "Spot Color".
6. You can change the color to visually represent the white ink spot color while viewing the file in the application. This helps distinguish the white ink spot color from areas that are blank or lack color data. It is recommended to choose a color that is not present in the original file for better clarity.
7. Once you have created the spot color swatch, it is ready to be used in the design of your file. The swatch is located in the Swatches window. It has a small dot in the lower right corner of the swatch to indicate that it is a spot color:
   
   
   
8. (Optional) You can adjust the density of the white ink using the slider or the numeric control in the Color window. Additionally, the Transparency slider also influences the density of the spot color, creating a cumulative effect. For example, a density of 70% combined with 50% transparency results in an effective total density of 35%.

(Optional) Step 2: Set Overprint for the Spot Color

Default mode (without overprint)

By default, when you create and print overlapping elements in Adobe Illustrator, the top element will knock out the area of the element beneath it. This behavior represents Adobe Illustrator's standard mode of operation.

Example

In the example below, a box was created using the spot color swatch (white ink), with orange text placed on top.

The orange text knocks out the spot color data beneath it, preventing the two colors from mixing. If this were printed on black media, the orange text would lack white ink underneath, making it difficult to see:

Overprint mode

On the other hand, overprinting prevents knockout and allows elements to print over or under one another. This feature is particularly important when using white ink as a spot color. To ensure that the artwork prints over or under the white ink, you must enable the overprint attribute.

Process

This option can be found under the Window menu in the Attributes panel. When you select your shape, the Fill and Stroke options will be displayed according to the object's properties, allowing you to customize its appearance effectively.

Example

In the example below, if printed on black media, the orange text would appear over a solid box of white ink:

Transparency between colors

It is important to know that this function is also effective when printing certain colors. If you need to see the transparency between them, you must also enable the corresponding attribute:

Step 3: Export the File

PDF format

To preserve the white ink data in transparent areas, you must save your file in PDF format version 1.4 or higher (version 1.7 is recommended). Avoid using any of the PDF/X standards, as most of them will flatten your transparent areas.

While it is possible to save Illustrator files with white ink data as PostScript (PS) or Encapsulated PostScript (EPS) files, it is important to note that only PDF supports transparency among these three file types.

This is crucial if your file contains white ink data that extends across a transparency bounding box. In such cases, saving as a PS or EPS file will flatten the transparency, resulting in the loss of the white ink data.

Composite or separation mode

When saving to PDF, Adobe Illustrator offers the option to output either a composite file or a separation file.

Composite files contain all image color data on a single page, providing a full-color display of your image when viewed. Most files you encounter will be composite files. However, when printing with white ink, composite PDF files are only effective if the spot color swatch in the file has a single density.

If the spot color swatch contains multiple densities or utilizes a gradient, the file must be saved as a separation file.

Step 4: Use the file in CalderaRIP

In CalderaRIP, spot inks and color separation are managed in the Print module > Page Setup.

Go to your spot ink tab and "Enable Separation". Then, select the Method for creating the spot ink layer (white in this example). The Method selection identifies which data will determine where the white ink is used:

For more information about the different options, see this article.

Troubleshooting

Why does the preview of my file differ from the printed output?

If the file contains overprints, basic file viewers typically do not support overprint previews, and prepress software may not display them by default. However, this does not prevent the printed output from meeting expectations.

To correctly view images with overprinting in Adobe software, please refer to the following Adobe support articles:

• Adobe Illustrator: link
• Adobe Acrobat Pro: link