Making Spot Color Separations from ColorPop Halftones
ColorPop Halftones builds the effect from overlapping dots, and where dots overlap you get a blended color. For screen printing with spot color separations, every one of those colors is a screen.
So the goal is to reduce the image to the fewest flat colors that still look good, then pull one plate per color. Save for Web does the reduction, the Color Table lets you fine-tune it, and spot channels give you the plates.
Step 1. Export a flattened, color-reduced PNG
With your ColorPop Halftones PSD open, go to File > Export > Save for Web (Legacy). Use these settings:
- Preset: PNG-8
- Colors: start around 8, then lower it
- Dither: No Dither
- Transparency: checked (if your design has a transparent background)
- Matte: None
- Interlaced: off
Halftone dots in this image are oversized for demonstration purposes. ColorPop Halftones allows you to use any size halftone dots and lines.
The No Dither setting removes anti-aliasing and blended edge pixels, so every pixel in the export is one of your exact colors. The edges will look slightly hard on screen, and that's what you want. A screen is either ink or no ink.
Now play with the Colors value. Watch the preview at 100% or 200%. Each color you remove is one less screen. Sometimes 4 looks great, sometimes it looks off and 5 or 6 is the right number. Pick the lowest count that still gives you the look you want, then Save.
Step 2. Fine-tune the palette in the Color Table
Open the PNG you just saved. It opens in Indexed Color mode with the palette intact. Go to Image > Mode > Color Table.
This is your control panel. Every color in the image is a swatch. If there's a color you don't want to print as its own screen, click its swatch and change it to match one of the other swatches. Those pixels merge into that color. This is more precise than just lowering the count in Save for Web, because you decide which overlap blend rounds to which ink. Click OK when done.
You can go back and forth between Steps 1 and 2 as much as you like.
Step 3. Convert to RGB
Image > Mode > RGB Color. Your colors stay exact; this just lets you make selections and channels.
Step 4. Pull one selection per color
Select the Magic Wand. In the options bar set Tolerance to 0, uncheck Anti-alias, uncheck Contiguous. Click one dot of a color and every pixel of that color in the image is selected.
Then, in the Channels panel menu, choose New Spot Channel. Name it, set the ink color to match, and set Solidity to 100%. Click OK, then Deselect.
Repeat for each color. When you're done you'll have one spot channel per screen, and the composite will preview with the correct ink colors.
Step 5. Check and save
To make sure nothing was missed, go to Select > Color Range with Fuzziness at 0 and shift-click each color; the selection should cover everything with no stray pixels. Save as PSD (or DCS 2.0). Each spot channel outputs as its own plate.