This video shows the process of designing a poster in Photoshop to be printed on the OKI C942. White toner is used both as standalone elements (white printed on its own) as well as under color (in this case, lime green) to protect the hue from the color of the media it’s being printed on.
The C942 can also selectively print color directly onto the media with no white behind it. This design uses a dark blue in this way to create shadow areas.
Starting with a pencil sketch, the image is inverted and then colorized to simulate the media color. This layer is then locked to prevent it from being altered unintentionally.
A new layer is created and white linework is rendered. These lines will later become the lime green elements.
Once these areas have been rendered completely, a new layer is created. The area from the previous white line layer is selected and filled with lime green and the Layer Mode is set to Multiply to simulate the way the printer will apply color over white toner.
Next, the shadow layer is created. A dark blue color is selected and rendered.
Another layer is created for the white highlights, which are then added using the brush tool.
Text elements are created using the same process described above.
In preparing the file for exporting and printing, both the initial white layer (the one used as the basis for green) as well as the white highlights layer are turned into an active selection.
Then, from the Channels tab, a new Spot Alpha Channel is created and named “SpotColor_White”. This channel name is carried through to the final PDF, telling the printer where to place white toner.
The background layer is turned off to prevent it from being printed.
Because Photoshop can not directly print files containing spot alpha channels, the file must be exported to PDF. A Save As is performed and Photoshop PDF is selected.
From the next menu, the PDF Standard of PDF/X1-a:2001 is selected. This is critical – the X1-a Standard is necessary to be able to carry the “SpotColor_White” spot alpha channel from Photoshp over to the final PDF file.
The PDF is then opened from Acrobat. In order to verify that the spot alpha channel was correctly named and exported, Print Production and then Output Preview is selected.
Finally, from the print menu, the Spot Color Usage Methods setting is set to Application Specification. This tells the C942 to place white toner only where it’s been defined in the file (other settings convert black in the file to white toner when printing, or place white toner behind all elements in a file).
Other settings selected for this type of piece are Media Type: Rough, Media Weight: Ultra Heavy 2, Trapping: Wide/Choke White, and Output Bin: Stacker (Face-up).