Pantone and HKS spot colors - it's not supported in free version PDFLib Lite
(PHP 4 >= 4.0.5, PECL pdflib >= 1.0.0)
PDF_makespotcolor — Make spot color
$p
, string $spotname
)
Finds a built-in spot color name, or makes a named spot color from the
current fill color. Returns TRUE on success or FALSE on failure.
Pantone and HKS spot colors - it's not supported in free version PDFLib Lite