Hello!

Is there a way to keep the "greyness" of grey objects when saving as pdf?

All objects are made of three-color-grey when analysing the pdf in Acrobat. Embedding a color profile in Inkscape makes no difference.
These objects should only contain plain grey color, when no "colorful" color is involved.

I could convert the pdfs to plain greyscale in Acrobat afterwards. But as a result of this process, the value of the grey colors changes. They become darker or lighter, which I do not want to happen.

Exporting as a bitmap might be ok, have to test it, but I prefere to not make it a permanent solution.

Hi.

Have a look at Lazur Uhr's post; viewtopic.php?f=5&t=16727#p61763

Good Luck
RGDS
Ragnar

Thank you!

This helped a little.
When converting PDFs to greyscale via Preflight in Acrobat, the colors get shifted too much, e.g. in Inkscape a plane is filled with 55% black, after Preflight it is 69%. With the Ghostscript script (...) you led me to, the changes are much smaller, e.g. from 55% to 62%. That means, the grey value gets only shifted by half of the amount that it would with Preflight. Same thing with other grey values.

I tested exporting to png in the meantime, too, and here the grey values stay correct, although the graphic can't be saved as greyscale (8bit) image because Inkscape lacks an option for that. Here, too, I have to convert the image afterwards, but Irfan View's greyscale converter keeps the colors and is fastly done via batch when necessary. Still a "is ok, but would be better to not have to use pixel graphics"-solution.

Hm, I think I have to look deeper into Ghostscript. Maybe there is a way to prevent the value-shifting or to compensate it.

Hi

For another option: http://stuffforlife.blogspot.com/2009/03/converting-color-pdf-to-black-and-white.html

RGDS
Ragnar

I found a solution for my problem.

Ghostscript meant to much scripting and I didn't find the right way for building gs- and batch- or perl-scripts doing what I wanted in an acceptable amount of time.
But I looked deeper into the Preflight-options in Acrobat and discovered a way to keep the grey color values nearer to the original from inkscape.

In the "PDF fixups" section there is a "convert to grayscale" profile. This I duplicated and edited.

And because the next steps are a bit hard to explain in short, I'll add two images below. In the end I had to choose "Dot Gain 30%" (it was "Dot Gain 15%" before) from the dropdown list in "Target" (?). With this the greyscale values aren't pushed above the original value then before. Instead they stay a little bit under the desired value, but not more than 4% difference (e.g. no alteration until 20% black, 1-2% alteration for 25%-45% and a maximum of 4% at 90% black, after that it gets nearer to original values again).