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Author Topic: [Scribus 1.5 svn] Using a spot color on a bitmap image  (Read 1815 times)

drBouvierLeduc

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[Scribus 1.5 svn] Using a spot color on a bitmap image
« on: September 01, 2014, 06:45:23 pm »
Hi,

Assigning a spot color to a vector shape is easy : you just need to choose the spot color in the colors panel, and that's it.
But how to do with a bitmap image ? Is it possible to get a preview of the result in the viewport, and the proper color separation for the print ?
I've tried 2 image filters which seem to "apply" a color to an image : « colorize » and « duotone », but the result is a CMYK composite.

By the way, I'm assuming that's it's technically possible to print a bitmap image with a spot color, but maybe it's not the case ?
I've  worked with spot colors used on vector shapes without problem in the past, so I guess there's no reason it shouldn't be possible for bitmap images.
But I'm not entirely sure, spot color are strange beasts !

Here you can see what I'm trying to get in a glance :

Marikus

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Re: [Scribus 1.5 svn] Using a spot color on a bitmap image
« Reply #1 on: September 26, 2014, 08:41:30 pm »
Dear drBouvierLeduc,

as nobody answered you until today I guess that this problem is not easily to solve. First I thougt of GIMP, but there are no spotcolors supported.
Maybe you can try this: Go to the "Pictureeffects" and convert your picture into greyscale. After that color (changing colors) it with your spot color.
Now export it to PDF.

I have no Idea if this could work as I don´t know how to find out about the spot colors included in an PDF. Adobe Reader didn´t tell me anything.

But maybe you can check with professional tools like acrobat. Please tell me the result as I am interested too.

If all the things would not work, I would try digitizing it in inkscape, then importing the svgs into inkscape and then set the colors to the spot color.

leaf

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Re: [Scribus 1.5 svn] Using a spot color on a bitmap image
« Reply #2 on: September 26, 2014, 11:35:29 pm »
Here is the solution
http://forums.scribus.net/index.php/topic,1229.0.html

... and ghostscript can tell if in pdf there is pantone because can separate channels - option in GS -sDEVICE=tiffsep -r150
« Last Edit: September 26, 2014, 11:40:05 pm by leaf »

drBouvierLeduc

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Re: [Scribus 1.5 svn] Using a spot color on a bitmap image
« Reply #3 on: October 03, 2014, 01:30:36 pm »
Hey, it seems I overlooked your responses.

@Marikus :
I tried using the greyscale filter before the colorize one, and even tried to convert my image to greyscale beforehand, but it doesn't work either.
For the lack of a better option, I indeed vectorize some of my bitmap images with inkscape, but it's only suitable for a few images. It wouldn't work for the image above for instance.

@Leaf :
So if I understand well, I could prepare my image in photoshop, export it as a pdf, and import that pdf into my scribus document ? I'll try that.
Also I did a search in the bug tracker, but couldn't find a bug report related to this issue. But the bug #3743 is exactly that, thanks for the link.

I forgot to mention something : in an earlier version of Scribus 1.5svn (~3 years ago), the colorize filter was sort of working with spot colors.
For images with a transparent background, I would first apply a filter in order to darken the image (contrast, curves or luminosity, whaterver), than I would apply the colorize filter.
As a result, my image was « filled » with the spot color. This isn't exactly what I want to get now, but it's close.

So I will keep an eye on the bug #3743 hoping it will be adressed someday.
By the way, spot colors with the duotone filter should work too.

I will also try the photoshop workaround, even though I would like very much to use only free software for my workflow.
Anyway, thanks for your answers.

leaf

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Re: [Scribus 1.5 svn] Using a spot color on a bitmap image
« Reply #4 on: October 03, 2014, 03:00:15 pm »
So if I understand well, I could prepare my image in photoshop, export it as a pdf, and import that pdf into my scribus document ? I'll try that.

I will also try the photoshop workaround, even though I would like very much to use only free software for my workflow.
Anyway, thanks for your answers.

@drBouvierLeduc
Yes solution with photoshop works. But I proposed 2 solutions yet and they are feasible/real for free programs: Scribus, Gimp or any other programs for bitmap - for 1 solution, and Scribus, Notepad++, ghostscript or pdftk for last solution - See the other side of the link too.
But solution with photoshop is simple. PS does all with spot color and Scribus only adopt ready pdf.

« Last Edit: October 03, 2014, 03:02:11 pm by leaf »