ghostscript preserve PDF input's font - pdf

Question

My ghostscript command is this:
gs \
-dBATCH -dNOPAUSE \
-sDEVICE=pdfwrite \
-dColorConversionStrategy=/LeaveColorUnchanged \
-dDownsampleMonoImages=false \
-dDownsampleGrayImages=false \
-dDownsampleColorImages=false \
-dAutoFilterColorImages=false \
-dAutoFilterGrayImages=false \
-dColorImageFilter=/FlateEncode \
-dGrayImageFilter=/FlateEncode \
-sOutputFile=./merge.pdf \
-f ./page_*.pdf
Most of the command are related to images.
After execution, I find that the fonts look less sharp than the input file.
The difference between the fonts is as follows:
Fonts of (one of) the input file:
$ pdffonts page_3.pdf
name type encoding emb sub uni object ID
------------------------------------ ----------------- ---------------- --- --- --- ---------
NachlieliCLM-Bold Type 1 Builtin yes no yes 62 0
NachlieliCLM-Bold Type 1 Custom yes no yes 65 0
Courier10PitchBT-Bold Type 1 Builtin yes no yes 70 0
EAAAAA+LiberationSerif TrueType WinAnsi yes yes yes 27 0
NachlieliCLM-Light Type 1 Builtin yes no yes 75 0
NachlieliCLM-Light Type 1 Custom yes no yes 78 0
HAAAAA+LiberationSans-Bold TrueType WinAnsi yes yes yes 42 0
IAAAAA+DejaVuSans TrueType WinAnsi yes yes yes 47 0
JAAAAA+LMMono9-Regular Type 1 Builtin yes yes yes 52 0
KAAAAA+LMMonoProp10-Regular Type 1 Builtin yes yes yes 37 0
Courier10PitchBT-Roman Type 1 Builtin yes no yes 83 0
MAAAAA+LiberationSerif-Bold TrueType WinAnsi yes yes yes 57 0
NAAAAA+LiberationSerif-Italic TrueType WinAnsi yes yes yes 32 0
Font of the output file:
$ pdffonts merge.pdf
name type encoding emb sub uni object ID
------------------------------------ ----------------- ---------------- --- --- --- ---------
LQRJGW+LiberationSerif-Bold TrueType WinAnsi yes yes yes 54 0
ZAZOKA+NachlieliCLM-Light Type 1C Custom yes yes yes 42 0
XFXEQZ+LiberationSerif-Italic TrueType WinAnsi yes yes yes 56 0
KBCNYY+LiberationSans-Bold TrueType WinAnsi yes yes yes 44 0
PPEMTT+DejaVuSans TrueType WinAnsi yes yes yes 46 0
FUVLBK+NachlieliCLM-Bold Type 1C Custom yes yes yes 36 0
OQFKGW+LMMono9-Regular Type 1C Custom yes yes no 48 0
ZFATCB+LMMonoProp10-Regular Type 1C Custom yes yes no 50 0
WIGEDL+Courier10PitchBT-Bold Type 1C WinAnsi yes yes no 38 0
AFLCKO+Courier10PitchBT-Roman Type 1C WinAnsi yes yes no 52 0
QNUNTR+LiberationSerif TrueType WinAnsi yes yes yes 40 0
BLSWAW+DejaVuSansMono TrueType WinAnsi yes yes yes 97 0
HQDKJN+LiberationSerif TrueType WinAnsi yes yes yes 99 0
SCAKLE+LiberationSerif-Italic TrueType WinAnsi yes yes yes 101 0
AGALJA+NachlieliCLM-Bold Type 1C Custom yes yes yes 91 0
PPEMTT+DejaVuSans TrueType WinAnsi yes yes yes 103 0
TLVEAY+LiberationSans-Bold TrueType WinAnsi yes yes yes 93 0
GLOKSW+NachlieliCLM-Light Type 1C Custom yes yes yes 95 0
The only method which PARTIALLY works is executing the following:
gs \
-dBATCH -dNOPAUSE \
-sDEVICE=pdfwrite \
-dCompressFonts=true \
-dSubsetFonts=true \
-dEmbedAllFonts=false \
-sOutputFile=./merge.pdf \
-f ./page_*.pdf
$ pdffonts merge.pdf
name type encoding emb sub uni object ID
------------------------------------ ----------------- ---------------- --- --- --- ---------
LQRJGW+LiberationSerif-Bold TrueType WinAnsi yes yes yes 54 0
NachlieliCLM-Light Type 1 Custom no no yes 42 0
XFXEQZ+LiberationSerif-Italic TrueType WinAnsi yes yes yes 56 0
KBCNYY+LiberationSans-Bold TrueType WinAnsi yes yes yes 44 0
PPEMTT+DejaVuSans TrueType WinAnsi yes yes yes 46 0
NachlieliCLM-Bold Type 1 Custom no no yes 36 0
EVJWAP+LMMono9-Regular Type 1C Custom yes yes no 48 0
LAKFSN+LMMonoProp10-Regular Type 1C Custom yes yes no 50 0
Courier10PitchBT-Bold Type 1 WinAnsi no no no 38 0
Courier10PitchBT-Roman Type 1 WinAnsi no no no 52 0
QNUNTR+LiberationSerif TrueType WinAnsi yes yes yes 40 0
BLSWAW+DejaVuSansMono TrueType WinAnsi yes yes yes 97 0
HQDKJN+LiberationSerif TrueType WinAnsi yes yes yes 99 0
SCAKLE+LiberationSerif-Italic TrueType WinAnsi yes yes yes 101 0
NachlieliCLM-Bold Type 1 Custom no no yes 91 0
PPEMTT+DejaVuSans TrueType WinAnsi yes yes yes 103 0
TLVEAY+LiberationSans-Bold TrueType WinAnsi yes yes yes 93 0
NachlieliCLM-Light Type 1 Custom no no yes 95 0
In the last case - the font LMMono9 doesn't change, but the font NachlieliCLM is sharper (probably due to that it is not embedded...).
As you can see - some of the fonts aren't embedded - which is bad.
The output PDF is intended for printing and sharing, therefore the fonts needs to be embedded and in high quality.
BTW, I know that the flags need to be as such:
-dCompressFonts=true \
-dSubsetFonts=false \
-dEmbedAllFonts=true \
But the fonts still not sharp with these flags.
I've read many SO threads and in documentation but failed to find a solution.
I suspect that I need the output font to be of type Type 1, instead of type Type 1C, but not sure.
Example:
There are attached two files: input.pdf and output.pdf.
There is a difference between them ONLY in the following text:
"Title is here (heading 2)" - Font is Courier 10 Pitch
Bullets "First" up to and including "Sixth" - Font is LM Mono 9
(Notice that the rest of the sentence in the bullets is fine - it doesn't change. Meaning that only the word numbers, like "First", are the ones who change.)
The last/bottom (Hebrew) sentence - Font is Nachlieli CLM
The difference is that in the output file, the text is more gross. (input is sharper). In order to see the difference, place the two PDF documents side by side, each having a zoom of 100%. The difference is noticeable with using either Ubuntu's default Document Viewer or Okular.
The rest of the text is the same.
Also indeed the input PDF file was created using LibreOffice 4.2.
The output file was created using the following command:
gs \
-dBATCH -dNOPAUSE \
-sDEVICE=pdfwrite \
-dColorConversionStrategy=/LeaveColorUnchanged \
-dDownsampleMonoImages=false \
-dDownsampleGrayImages=false \
-dDownsampleColorImages=false \
-dAutoFilterColorImages=false \
-dAutoFilterGrayImages=false \
-dColorImageFilter=/FlateEncode \
-dGrayImageFilter=/FlateEncode \
-sOutputFile=./output.pdf \
-f ./input.pdf
I'm using GPL Ghostscript 9.10 and Ubuntu 14.04.
Screenshot to show the differences between input (pre-GS) and output (post GS). Used the software Document Viewer 3.10 (or Evince).

Answer 1

No the font format is not an issue. Type 1C is simply CFF format which is (more or less) a more compact representation of a type 1 font.
You don't say which operating system you are using, nor which version of Ghostscript.
Its not possible to tell you anything about what is happening without an example. Please post an input file somewhere where we can look at it and then we might be able to help you.
Converting to type 1C is a simple matter and does not affect the font 'sharpness' since both are vector forms. You will not get a type 1 font out of pdfwrite, all type 1 fonts are converted to CFF (type 1C).
The reason NachlieliCLM is not embedded is that have set EmbedAllFonts=false, and its not subset and uses the default Encoding. A subset input font needs to be embedded, because it almost invariably uses a custom Encoding, so you can't simply use the original font in its place.
I suspect, but can't prove without seeing the input, that your problem is due to the poor naming convention used by certain PDF-producing applications. The subset is not unique, causing name collisions. LibreOffice is a known culprit here.
That problem was believed resolved recently (we now additionally use the PDF object number as well the font name) but since I don't know what version of Ghostscript you are using I can't say whether that's likely to be the problem. However that normally causes incorrect characters, not a loss of 'sharpness' which is more likely to be caused by rendering to an image.
As I said, post a (small) example input file and the result you get from Ghostscript and pdfwrite, and it might be possible to say more.

Answer 2

I don't know how current your question is but today I faced a similar issue as yours and I found out using pdffonts that my output after merging does not contain the same fonts as my source resulting in unsharp and unpretty characters. I solved the problem in putting all fonts used by the input in a specific folder and then I called ghostscript with following arguments:
gs -sFONTPATH=<my_folder> \
-dEmbedAllFonts=true \
-sOutputFile=<my_output>.pdf \
<my_input>.pdf
Input and output pdfs matched after that! BTW: I am currectly using gs 9.25.0