well I've given up. I don't think I understand how GS works... as far as I understand GS replaces all fonts that are not embedded and should not touch already embedded ones? why is it replacing them? I have a pdf file that contains 2 embedded fonts and 1 not embedded (ArialMT).
I'm using command:
"gswin64c.exe -I "C:/Program Files/gs/gs9.56.1/Resource/Init" -sFONTMAP="Fontmap.GS" -dNOSAFER -dPDFACompatibilityPolicy=1 -sColorConversionStrategy=LeaveColorUnchanged -dBATCH -dNOPAUSE -sDEVICE="pdfwrite" -dAutoRotatePages=/None -dPDFA=3 -sOutputFile="pdfa.pdf" "original.pdf"
all I get with this command is this error:
GPL Ghostscript 9.56.1: Actual TT subtable offset xxxxx differs from one in the TT header yyyy. (multiple ones like this)
The following errors were encountered at least once while processing this file:
error executing PDF token
**** This file had errors that were repaired or ignored.
**** The file was produced by:
**** >>>> StreamServe Communication Server 16.6.1 GA Build 319 (64 bit) <<<<
**** Please notify the author of the software that produced this
**** file that it does not conform to Adobe's published PDF
**** specification.
the output is a pdf without ANY fonts...
- is there any way to force GS not to replace font if it wasn't found on the system?
- why is it replacing ArialMT with NimbusSans-Regular even though I have declared a specific path to ArialMT in my FontMap.GS file?
I'd rather not share this pdf file as it contains sensitive customer data.
(osadzony podzestaw=embedded subset)

