XnView Software

Hi all !

I'd like to use nconvert to convert EPS files (with a transparent background by design) to PNGs (256 colors, indexed).
If I try :
nconvert -o my.png -out png -dpi 140 my.eps
it works fine : I get a nice png with a white background.
But if I try :
nconvert -o my.png -out png -dpi 140 -colors 256 my.eps
the resulting file has a bluish background color (248,252,249).

The original file is almost only tranparent with some lines and texts (it's a map, actually), and I really need to preserve a white background.
Is there a way to achieve this ?

Thanks for helping !

Bingo wrote:Hi all !

I'd like to use nconvert to convert EPS files (with a transparent background by design) to PNGs (256 colors, indexed).
If I try :
nconvert -o my.png -out png -dpi 140 my.eps
it works fine : I get a nice png with a white background.
But if I try :
nconvert -o my.png -out png -dpi 140 -colors 256 my.eps
the resulting file has a bluish background color (248,252,249).

The original file is almost only tranparent with some lines and texts (it's a map, actually), and I really need to preserve a white background.
Is there a way to achieve this ?

No sorry, it's ghostscript

Okay.
Now if I convert to PNG (16m colors), and then reprocess the image to reduce colors to 256, can I keep my white... white ?

Bingo wrote:Okay.
Now if I convert to PNG (16m colors), and then reprocess the image to reduce colors to 256, can I keep my white... white ?

Try, if you have a lot of white, white will be white

xnview wrote:

Bingo wrote:Okay.
Now if I convert to PNG (16m colors), and then reprocess the image to reduce colors to 256, can I keep my white... white ?

Try, if you have a lot of white, white will be white

I tried, but white is not white.
I really have a lot of white though ! I'd say around 95% maybe.

Bingo wrote:

xnview wrote:

Bingo wrote:Okay.
Now if I convert to PNG (16m colors), and then reprocess the image to reduce colors to 256, can I keep my white... white ?

Try, if you have a lot of white, white will be white

I tried, but white is not white.
I really have a lot of white though ! I'd say around 95% maybe.

Could you send me the PNG 16m?

Of course.
I'll send it to you tomorrow morning.

OK, pm sent with link to the image.
Thanks for helping Pierre.

Pierre,
Have you found something new about this matter ?

Arnaud

Bingo wrote:Have you found something new about this matter ?

Do you have received my reply by pm?

xnview wrote:Do you have received my reply by pm?

Yes I have.
You noticed that their was no problem when "-dither" was used, but I was wondering whether you had found a solution for non-dithered conversions ?

Best regards,
Arnaud

Pierre,

Are you planning on releasing a new build of nconvert ?
I am still in a test period, but I have to write batch jobs, and I would have liked to know whether I could write nconvert command lines, or if I had to write them using mogrify (which works but is horribly slow!!!).

Best regards,
Arnaud

Bingo wrote:Are you planning on releasing a new build of nconvert ?
I am still in a test period, but I have to write batch jobs, and I would have liked to know whether I could write nconvert command lines, or if I had to write them using mogrify (which works but is horribly slow!!!).

But with the -dither, all is ok, no?

xnview wrote:But with the -dither, all is ok, no?

Yes, but the output is... dithered !
I do not want dithering in the output images, I need plain colors.

Bingo wrote:

xnview wrote:But with the -dither, all is ok, no?

Yes, but the output is... dithered !
I do not want dithering in the output images, I need plain colors.

Yes, right. There is a problem because when i quantize picture, i reduce bits per component, so after white is no more white
You can try with other software, you'll have same result.
But do you have same result with ImageMagick?