Pdflib PCOS get color space

I’m trying to get the color spaces being used in the file that I am importing using pdflib pcos, and iam getting this error.

“Fatal error: Uncaught PDFlibException: Can’t retrieve object ‘colorspaces[0]/name’ in evaluation mode
(only small documents)…”

Below is my code in php:

   $colorspace_count = $s->pcos_get_number($sraw, "length:colorspaces");
   for ($i = 0; $i <= ($colorspace_count-1); $i++) {
      $color_type[] = $s->pcos_get_string($sraw, "colorspaces[".$i."]/name");
   }
   $color_list = implode(', ',$color_type);