[gentoo-user] PDF: convert to grayscale

[gentoo-user] PDF: convert to grayscale

[Nuno J. Silva]

Does anyone know a tool (other than ghostscript) that is able to convert
a PDF (or postscript) to grayscale?

Ghostscript does this, but is unable to convert gradients and fills
(they're replaced by bitmaps) which results in a too big file unless I
drastically reduce quality.

-- 
Nuno J. Silva
gopher://sdf-eu.org/1/users/njsg

Re: [gentoo-user] PDF: convert to grayscale

[Michael Orlitzky]

On 02/08/11 08:50, Nuno J. Silva wrote:
> Does anyone know a tool (other than ghostscript) that is able to convert
> a PDF (or postscript) to grayscale?

A laserjet? =)

[gentoo-user] Re: PDF: convert to grayscale

[Grant Edwards]

On 2011-02-08, Nuno J. Silva <nunojsilva@ist.utl.pt> wrote:
> Does anyone know a tool (other than ghostscript) that is able to convert
> a PDF (or postscript) to grayscale?
>
> Ghostscript does this, but is unable to convert gradients and fills
> (they're replaced by bitmaps) which results in a too big file unless I
> drastically reduce quality.

I don't understand what you're asking for.  What sort of output format
do you want (raster, vector, ???)?

-- 
Grant Edwards               grant.b.edwards        Yow! Send your questions to
                                  at               ``ASK ZIPPY'', Box 40474,
                              gmail.com            San Francisco, CA 94140,
                                                   USA

Re: [gentoo-user] PDF: convert to grayscale

[Alex Schuster]

Grant Edwards writes:

> On 2011-02-08, Nuno J. Silva <nunojsilva@ist.utl.pt> wrote:
> > Does anyone know a tool (other than ghostscript) that is able to
> > convert a PDF (or postscript) to grayscale?
> > 
> > Ghostscript does this, but is unable to convert gradients and fills
> > (they're replaced by bitmaps) which results in a too big file unless I
> > drastically reduce quality.
> 
> I don't understand what you're asking for.  What sort of output format
> do you want (raster, vector, ???)?

I think he wants the same PDF as the original file. Only in grayscale.

This is one method to do this, but it needs Acrobat 8 Professional:
http://blog.gilbertconsulting.com/2007/05/convert-color-pdf-to-grayscale.html

	Wonko

Re: [gentoo-user] PDF: convert to grayscale

[Paul Hartman]

On Tue, Feb 8, 2011 at 7:50 AM, Nuno J. Silva <nunojsilva@ist.utl.pt> wrote:
> Does anyone know a tool (other than ghostscript) that is able to convert
> a PDF (or postscript) to grayscale?
>
> Ghostscript does this, but is unable to convert gradients and fills
> (they're replaced by bitmaps) which results in a too big file unless I
> drastically reduce quality.

Are you the creator of the document and want to save the original as
greyscale, or you want to convert an already existing PDF?

If the latter I think the easy way is to use ghostscript (pdf2ps) to
render it as greyscale postscript. Then you could convert the PS back
to PDF if you need to. But if you already tried that, then, I don't
know...

Re: [gentoo-user] PDF: convert to grayscale

[Matthew Summers]

On Fri, Feb 11, 2011 at 4:07 PM, Paul Hartman
<paul.hartman+gentoo@gmail.com> wrote:
> On Tue, Feb 8, 2011 at 7:50 AM, Nuno J. Silva <nunojsilva@ist.utl.pt> wrote:
>> Does anyone know a tool (other than ghostscript) that is able to convert
>> a PDF (or postscript) to grayscale?
>>
>> Ghostscript does this, but is unable to convert gradients and fills
>> (they're replaced by bitmaps) which results in a too big file unless I
>> drastically reduce quality.
>
> Are you the creator of the document and want to save the original as
> greyscale, or you want to convert an already existing PDF?
>
> If the latter I think the easy way is to use ghostscript (pdf2ps) to
> render it as greyscale postscript. Then you could convert the PS back
> to PDF if you need to. But if you already tried that, then, I don't
> know...
>
>

Use the GIMP, Luke. I have to do this all the time with forms and
such. The GIMP imports PDF files nicely, and I usually print the file
to PDF after I am done. Now, if you have a many page document, the
GIMP will import each page as a layer which can make it a pain to have
to manually print each layer as a separate pdf, but ya do what ya
gotta do. I also like PDFShuffler for managing/mangling pdf files. Its
in portage by the way.

HTH,
quantum
-- 
Matthew W. Summers

[gentoo-user] Re: PDF: convert to grayscale

[Nuno J. Silva]

(Sorry for the late replies)

Matthew Summers <quantumsummers@gentoo.org> writes:
> <paul.hartman+gentoo@gmail.com> wrote:
>> On Tue, Feb 8, 2011 at 7:50 AM, Nuno J. Silva <nunojsilva@ist.utl.pt> wrote:
>>> Does anyone know a tool (other than ghostscript) that is able to convert
>>> a PDF (or postscript) to grayscale?
[...]
> Use the GIMP, Luke. I have to do this all the time with forms and
> such. The GIMP imports PDF files nicely, and I usually print the file
> to PDF after I am done. Now, if you have a many page document, the
> GIMP will import each page as a layer which can make it a pain to have
> to manually print each layer as a separate pdf, but ya do what ya
> gotta do. I also like PDFShuffler for managing/mangling pdf files. Its
> in portage by the way.

GIMP will make it raster, and my goal was keeping it vectorial.

BTW, if you happen to, for some reason, convert pdf to raster
frequently, see ImageMagick's convert, which for some output formats (at
least png and jpeg) does a batch export of all pages (as separate
files). It will probably be handy when the PDF has many pages.

-- 
Nuno J. Silva
gopher://sdf-eu.org/1/users/njsg

[gentoo-user] Re: PDF: convert to grayscale

[Nuno J. Silva]

Paul Hartman <paul.hartman+gentoo@gmail.com> writes:

> On Tue, Feb 8, 2011 at 7:50 AM, Nuno J. Silva <nunojsilva@ist.utl.pt> wrote:
>> Does anyone know a tool (other than ghostscript) that is able to convert
>> a PDF (or postscript) to grayscale?
>>
>> Ghostscript does this, but is unable to convert gradients and fills
>> (they're replaced by bitmaps) which results in a too big file unless I
>> drastically reduce quality.
>
> Are you the creator of the document and want to save the original as
> greyscale, or you want to convert an already existing PDF?

All I have are PDFs, without any original file.

> If the latter I think the easy way is to use ghostscript (pdf2ps) to
> render it as greyscale postscript. Then you could convert the PS back
> to PDF if you need to. But if you already tried that, then, I don't
> know...

From what I've been reading, it's always better to use pdftops (poppler)
because pdf2ps generates lower-level stuff and also converts fonts to
bitmap. But both ways, I'd end up doing the conversion in ghostscript,
and that's where the problem is.

-- 
Nuno J. Silva
gopher://sdf-eu.org/1/users/njsg

[gentoo-user] Re: PDF: convert to grayscale

[Nuno J. Silva]

Alex Schuster <wonko@wonkology.org> writes:

> Grant Edwards writes:
>
>> On 2011-02-08, Nuno J. Silva <nunojsilva@ist.utl.pt> wrote:
>> > Does anyone know a tool (other than ghostscript) that is able to
>> > convert a PDF (or postscript) to grayscale?
>> > 
>> > Ghostscript does this, but is unable to convert gradients and fills
>> > (they're replaced by bitmaps) which results in a too big file unless I
>> > drastically reduce quality.
>> 
>> I don't understand what you're asking for.  What sort of output format
>> do you want (raster, vector, ???)?
>
> I think he wants the same PDF as the original file. Only in grayscale.

Yeah, that's it. I ended up hacking the PDF to convert all RGB to
grayscale, but even if the result was the original without colors (what
I wanted), converting it to ghostscript made some text unreadable (white
on white), so it was clearly not a good idea to trust it to look the
same everywhere.

I gave up and used the color version.

> This is one method to do this, but it needs Acrobat 8 Professional:
> http://blog.gilbertconsulting.com/2007/05/convert-color-pdf-to-grayscale.html

Thanks for the link. Although I don't have Acrobat, if I ever happen to
get access to it I'll probably check that feature :-)

-- 
Nuno J. Silva
gopher://sdf-eu.org/1/users/njsg

[gentoo-user] [OT] Re: PDF: convert to grayscale

[Nuno J. Silva]

Michael Orlitzky <michael@orlitzky.com> writes:

> On 02/08/11 08:50, Nuno J. Silva wrote:
>> Does anyone know a tool (other than ghostscript) that is able to convert
>> a PDF (or postscript) to grayscale?
>
> A laserjet? =)

That makes me wonder... in a color printer, I expect it not to print any
color when it has no color ink, but do grayscale printers apply some
conversion internally, to make sure that e.g. plain cyan is still
visible (instead of making it white)?

-- 
Nuno J. Silva
gopher://sdf-eu.org/1/users/njsg

Re: [gentoo-user] PDF: convert to grayscale

[Valmor de Almeida]

On 02/08/2011 08:50 AM, Nuno J. Silva wrote:
> Does anyone know a tool (other than ghostscript) that is able to convert
> a PDF (or postscript) to grayscale?
> 
> Ghostscript does this, but is unable to convert gradients and fills
> (they're replaced by bitmaps) which results in a too big file unless I
> drastically reduce quality.
> 

Have you tried inkscape? it is in portage.

--
Valmor

[gentoo-user] Re: [OT] Re: PDF: convert to grayscale

[Grant Edwards]

On 2011-02-27, Nuno J. Silva <nunojsilva@ist.utl.pt> wrote:
> Michael Orlitzky <michael@orlitzky.com> writes:
>
>> On 02/08/11 08:50, Nuno J. Silva wrote:
>>> Does anyone know a tool (other than ghostscript) that is able to convert
>>> a PDF (or postscript) to grayscale?
>>
>> A laserjet? =)
>
> That makes me wonder... in a color printer, I expect it not to print any
> color when it has no color ink, but do grayscale printers apply some
> conversion internally, to make sure that e.g. plain cyan is still
> visible (instead of making it white)?

No.

No matter what transformation you use from a 3-dimensional space into
a 1-dimensional space, there will be sets of values that differ in the
3-dimensional space which map to identical values in the 1-dimensional
space.

-- 
Grant Edwards               grant.b.edwards        Yow! I'm in direct contact
                                  at               with many advanced fun
                              gmail.com            CONCEPTS.

Re: [gentoo-user] Re: [OT] Re: PDF: convert to grayscale

[Willie Wong]

On Mon, Feb 28, 2011 at 03:08:23PM +0000, Grant Edwards wrote:
> > That makes me wonder... in a color printer, I expect it not to print any
> > color when it has no color ink, but do grayscale printers apply some
> > conversion internally, to make sure that e.g. plain cyan is still
> > visible (instead of making it white)?
> 
> No.
> 
> No matter what transformation you use from a 3-dimensional space into
> a 1-dimensional space, there will be sets of values that differ in the
> 3-dimensional space which map to identical values in the 1-dimensional
> space.

But it is trivial to make a transformation that maps to certain sets
of values not more than once. In particular, there's nothing barring
the printer to make it so that only pure white and pure black gets
mapped to white and black, and everything else maps (nonuniquely) to a
shade of grey. 

W
-- 
Willie W. Wong                                     wwong@math.princeton.edu
Data aequatione quotcunque fluentes quantitae involvente fluxiones invenire 
         et vice versa   ~~~  I. Newton