Visual Foxpro Application creates PDF file using Infotec PS printer driver and Ghostscript 9.20 using gsdll32.dll
with parameters
-dNOPAUSE -dBATCH -dSAFER -dPDFSETTINGS=/screen -r300 -sDEVICE=pdfwrite
-sOutputFile=file.pdf -c .setpdfwrite -f inputfile.ps
PDF contains image Image size is bigger and it is shrinked in pdf to creeate smaller logo. Image has single color. Image in pdf appears dirty and there are pixels with other colors.
How to fix this so that image appears sharp and contians only sinle color ? Is it possible to change some Ghostscript printer diver settins or windows PS printer driver settings.
Original image is bigger and has good quality.
Firstly, don't use -dPDFSETTINGS=/screen. That is intended to reduce file sizes suitable for screen resolution, it also sets a whole host of configurations. Better by far to understand what you are doing and select only the ones you want to change.
Now quite clearly the image has been quantised (ie it has been turned into a JPEG), and flat coloured images are unsuitable candidates for JPEG compression which relies on the image being Photographic (JPEG = Joint Photographic Experts Group).
If you don't want your images compressed as JPEG then you'll have to alter the ColorImageFilter, which is covered in the documentation.
As I've mentioned to other people recently, its my belief that Artifex (the copyright owners) will regard linking to the Ghostscript DLL as a 'derivative work' under the AGPL and so you will need to make the source to your application open-source, or seek a commercial licence.