Printing multiple layers with special inks

Note: This feature is available only for production printers that support multi-layer printing with special inks such as white, metallic, and clear inks.

Some printers support printing multiple ink layers. For example, white ink can be used as an undercoat to increase image opacity when printing on transparent media. Metallic ink can be printed as a solid tone or combined with CMYK inks to create a wide range of metallic and pearlescent effects.

Instead of creating separate print jobs for each layer of white, metallic, or clear ink, you can conveniently define all print layers on the Layers tab (Job > Printer Settings > Print Layers). After each layer is printed, the printer automatically repositions the media to its starting point for the next layer. The printing order of the layers can be customized as needed.

Different print layers for special inks can be configured in a single job, for example:

Automated layer printing in one job

Let's assume you want to proof an image with 6 image channels: CMYK, white and clear ink. To view the channels of a selected image, you can click on the Color Management > Channels page. On the Printer Settings > Printer page, you can check the preselected calibration set. As for technical reasons white and clear ink cannot be printed at the same time, you need to either choose a calibration set with a CMYK Only color mode or include white and select a W|CMYK color mode instead. The remaining layers can be selected on the Layers tab, as shown on the below screenshot.

The Main Job Layer includes all colors covered by the selected calibration set on the Printer tab, in this case CMYK. In addition to the main layer, White and Gloss will be printed in our example (1). The Order column (2) reflects the order in which the layers will be printed which can be changed by clicking the arrow buttons on the left. In our example, we want to print a white coating onto the print medium before applying CMYK. If a validator message prompts you to select a different color mode for a layer, click on the respective Change Settings buttons (3) to open the layer settings.

The layer settings can also be used to change the resolution of a layer. With Number of Copies and Overprint you can multiply the selected layer. When selecting several copies of a layer, this layer will be printed several times one layer after the other with drying in between, whereas when selecting overprint passes, the print head will print the same line several times right on top of each other.

Please note that the job and image preview do not visualize the configured print sequence. Consequently, layer-order issues, such as a white undercoat being printed above the CMYK layer, are not indicated in the preview.

Manual layer printing via multiple jobs

If you want to manually define your layers or need a special layering not supported by the Print Layers functionality, you need to enable the option Print Images on Top of Each Other as shown on the following screenshot, so that the print medium is automatically pulled back to its initial position, ready to print the next layer.

Special inks as spot colors

Special inks are handled as spot colors in GMG ColorProof. A spot color can be defined with up to three special inks. If a spot color contains color data for multiple image channels, white takes precedence and the spot will be displayed on top of the Channels list (Color Management > Channels). The image channel order can be changed according to your requirements. If you, however, redefine a spot color after the channel list has once been arranged, it is not automatically updated accordingly.

Special inks are all printed in a separate layer except Silver (Blended) which is printed together with the CMYK layer. The spot color sets that simulate spot colors with special inks have been suffixed with the respective ink (for example Silver or Silver Blended). This way, the appropriate sets (Printer tab > Spot Color Priority list) can be easily recognized and the search sequence customized.