Flood Coats
A white flood coat will even out the background surface, dramatically reducing the potential interference of the clear inner hub and the mirror band. Sometimes printing a white flood followed by a colored flood can be effective: Black ink on a yellow background should be handled like so: |
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Composite
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Pass#1: White Flood
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Pass#2: Process Yellow
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Pass#3: Black
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The Duotone That's Really a Monotone over a flood
In order to get the solid yellow above, it was necessary to change the curve of one of the ink colors in a Photoshop duotone to be flat: output at 100%, no matter what the input. The default setting for duotones in Photoshop is for the input and the output to be equal; by tweaking the curve, you can make Photoshop output a solid plate.
Here's the default (input = output): |
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| Here, we compress the tonal range so that the output is limited to the 50-100% range. Observe how the slant of the line in the box next to "Yellow" has changed: |
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| Here, we compress the tonal range down to a single value - 100%. It seems as though the line has disappeared altogether, but it hasn't - it's just flatlined at 100% as you can see from the "Duotone Curve" screenshot below this one: |
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| Here are the corresponding composite images, and the greyscale representations of their Yellow channel information: |
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Duotone curve for yellow channel
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Yellow channel
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Composite
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Duotone curve for yellow channel
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Yellow channel
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Composite
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Duotone curve for yellow channel
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Yellow channel
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Composite
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| The third duotone curve, which calls for a solid coat of yellow ink, is the one that was used. This disc design is very safe - there are no overlapping halftones, which removes a whole class of potential complications from the realm of possibility. It will print predictably, with a smaller range of variation from run to run. |
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