Fix Ghostscript stackunderflow Error in PDF Conversion

When converting PostScript to PDF using ps2pdf with certain PDFSETTINGS options, you may hit this error:

GPL Ghostscript 9.10: Set UseCIEColor for UseDeviceIndependentColor to work properly.
Unrecoverable error: stackunderflow in .setdistillerparams

This occurs when Ghostscript’s internal stack runs out of expected values during PDF distiller parameter processing. The root cause is usually conflicting color space settings or incompatible parameter combinations that don’t work together.

Quick fix: Disable color conversion

The most reliable solution is to prevent Ghostscript from attempting color space conversions:

ps2pdf -dColorConversionStrategy=/LeaveColorUnchanged \
  -dPDFSETTINGS=/printer input.ps output.pdf

This preserves your PostScript file’s original color spaces without triggering the distiller stack issue. Use this as your default approach for print workflows.

Alternative: Use prepress settings

If you need PDFSETTINGS, switch from /printer to /prepress:

ps2pdf -dPDFSETTINGS=/prepress input.ps output.pdf

The prepress profile uses more conservative parameter combinations and typically avoids conflicting settings.

Direct Ghostscript approach for print output

For better control over print-destined PDFs, bypass ps2pdf and call Ghostscript directly:

gs -q -dNOPAUSE -dBATCH -dSAFER \
  -dMediaClass=Letter \
  -dDEVICEWIDTHPOINTS=612 \
  -dDEVICEHEIGHTPOINTS=792 \
  -dFitPage \
  -sDEVICE=pdfwrite \
  -sOutputFile=output.pdf \
  input.ps

This approach gives you explicit control over output dimensions and color handling without relying on preset PDFSETTINGS combinations that might conflict.

Explicit color handling parameters

If you need fine-grained control, specify color settings directly:

ps2pdf -dEmbedAllFonts=true \
  -dSubsetFonts=true \
  -dColorConversionStrategy=/RGB \
  -dProcessColorModel=/DeviceRGB \
  input.ps output.pdf

Avoid mixing -dColorConversionStrategy with -dPDFSETTINGS in the same command, as this commonly triggers the stack underflow.

Why the error happens

The stackunderflow in .setdistillerparams indicates internal parameter stack exhaustion. Common culprits:

CIE color space requirements conflicting with device color models
Multiple contradictory color conversion flags set simultaneously
PostScript color space definitions clashing with PDFSETTINGS expectations
Mixing high-level PDFSETTINGS with low-level device parameters

Version considerations

If you’re running Ghostscript 9.10 or older (check with gs --version), update to a current version:

sudo apt install ghostscript  # Debian/Ubuntu
sudo dnf install ghostscript  # Fedora/RHEL

Modern versions handle color space management and parameter stacking much more robustly. Most issues disappear after updating.

Debugging tips

To see what Ghostscript is processing, add verbose output:

ps2pdf -dDEBUG -dNOPAUSE -dColorConversionStrategy=/LeaveColorUnchanged \
  -dPDFSETTINGS=/printer input.ps output.pdf 2>&1 | head -50

If you still hit errors with the LeaveColorUnchanged approach, your PostScript file itself may have structural issues. Test with a simple PostScript file first to isolate whether the problem is file-specific or configuration-wide.