Spot Color Preservation Conflict Between Illustrator Asset Export Panel and Production SVG Workflow

Answer to the Core Question

The spot‑color loss occurs because the Asset Export panel does not expose the Preserve Spot Colors option, and the downstream SVG optimizer removes <defs> blocks that contain spot‑color definitions.

How Asset Export Controls Spot‑Color Preservation

• In Illustrator 2023+ the full Export As… dialog offers two checkboxes that matter:
  
  • Preserve Illustrator Editing Capabilities – keeps the original color objects.
  • Preserve Spot Colors – writes spot‑color definitions into an SVG <defs> section as spotcolor entries.
• The Asset Export panel itself (the quick‑export sidebar) does not show these options; you must use File > Export > Export As… to reach them.

How Production SVG Optimizers Handle Spot Colors

• Common tools such as SVGO, svgcleaner, or custom pipelines often enable plugins like removeUselessDefs or removeUnknowns that strip <defs> tags, including spot‑color <style> blocks.
• Unless the optimizer is configured to keep spotcolor definitions, the spot colors are either converted to flat RGB or dropped entirely.

Confirmed Facts (Illustrator 2023+)

1. The Preserve Spot Colors checkbox exists only in the full Export As dialog.
2. SVGO removes spotcolor definitions unless explicitly told to keep them.
3. PDF export retains spot colors by default.

Steps to Preserve Spot Colors in Your Workflow

1. Open the Illustrator file.
2. Navigate to File > Export > Export As… and choose SVG.
3. In the SVG options dialog, check both Preserve Illustrator Editing Capabilities and Preserve Spot Colors.
4. Export and open the SVG source in a text editor; you should see a <defs> section containing spotcolor entries.
5. Adjust your production optimizer:
   • For SVGO, add a custom plugin or set removeUselessDefs: false and removeUnknowns: false to keep the <defs> block.
   • For other tools, consult their docs for preserving defs or disabling spot‑color stripping.
6. Run a preflight check in the downstream print or color‑management tool to confirm the spot colors are still present.

Alternative Path if Optimizer Cannot Be Re‑configured

• Export the document to PDF with spot colors preserved.
• Use a PDF‑to‑SVG converter that supports spot‑color retention (e.g., pdf2svg with the --preserve-spot-colors flag if available).
• Proceed with your production pipeline on the resulting SVG.

Missing Diagnostic Detail

To fine‑tune the optimizer configuration, could you specify which SVG optimizer (SVGO, svgcleaner, or a custom tool) you are using and its current plugin list?