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Scribus => PDF Generation => Topic started by: mnawij on January 14, 2014, 05:44:57 am

Title: spot color images becomes CMYK
Post by: mnawij on January 14, 2014, 05:44:57 am
I have 2 different images (1bit) black/white .png files with transparent backgrounds in my design and I applied a different spot color to each.  When I export to .ps/.eps then convert to .pdf with Adobe Distiller AND exporting to .pdf straight from Scribus versions 1.4, 1.5, and PDFX (with all color management turned on), the images get converted to CMYK (I confirmed this with Enfocus Pitstop) after trying to print.  I apply the spot color by using image effects-->colorize.  Is this possible?  My printshop prints 90% spot colors and this is a must for my workflow...I have done this hundreds of times from InDesign with no problems.  This is not an InDesign vs. Scribus, but is possible in pdf creation is the only reason I bring this point up.

Thanks.

PS and yes I did not check the convert spot to CMYK.

Files attached.

Scribus 1.4.3 on Mac OS X 10.8
Title: Re: spot color images becomes CMYK
Post by: Nermander on January 14, 2014, 08:16:15 am
Are you 100% sure you didn't tick the Convert spot colors to CMYK checkbock?

See second image here
http://documentation.scribus.net/index.php/Spot_Colors

I've never used spot colors other than for a few test pages so I'm not sure how the colorize function works with spot colors.
Title: Re: spot color images becomes CMYK
Post by: utnik on January 14, 2014, 09:21:56 am
hi mnawij

Are you 100% sure you didn't tick the Convert spot colors to CMYK checkbock?

afaik by default this box is checked – you have to uncheck it to keep your spot colors!

utnik
Title: Re: spot color images becomes CMYK
Post by: leaf on January 14, 2014, 05:59:54 pm
mnawij
It is deficiency in Scribus. More is here http://bugs.scribus.net/my_view_page.php
But are three separate tricks.
1. Convert Your raster in vector graphisc. (problem is only for bitmaps)
2. Use Cyan as Your one Pantone blue, and Magenta as second Red Pantone. Next tell in PrintHouse to replace Magenta and Cyan in your spot colors.
3. I attach my solution, for analysis. (important to prepare other way bitmaps)
Title: Re: spot color images becomes CMYK
Post by: utnik on January 14, 2014, 08:55:50 pm
hi leaf

could you provide a link to the related bug report – i didn't know about this, but i'm interested in it…

utnik
Title: Re: spot color images becomes CMYK
Post by: mnawij on January 14, 2014, 09:00:59 pm
Thanks leaf

Yes I know about converting to vector, basically it boils down to time, $$$, or hardcopy artwork that we have had for 50+ years.  I use vectormagic.com for the conversions.
Yes I did know the trick about coloring with Cyan/Magenta/Yellow Plates, but I have had vendors reject it or their designers did not understand what to do even with clear explanations.
Do you have the bug # so I can follow it, I tried a quick search for with no luck.

mnawij
Title: Re: spot color images becomes CMYK
Post by: mnawij on January 14, 2014, 09:17:13 pm
utnik, here is the bug:

Issue # 0003743

I am new to the forums, how do you add comments in the bug tracker system, this problem has been around since 1.3 it looks like.  I thought I read that PDF 'printing' related issues gets high priority.  I would think that this is a pdf print related issue.

mnawij
Title: Re: spot color images becomes CMYK
Post by: utnik on January 14, 2014, 10:14:54 pm
hi mnawij

thanks for the bug nr.
i'll take a closer look at it, when i can find some time – looks like a complex of many color related bugs…

…how do you add comments in the bug tracker system…

you need an acount to mantis bug tracker – but afaik there are some problems for new members to log in…

utnik
Title: Re: spot color images becomes CMYK
Post by: Nermander on January 15, 2014, 08:13:53 am
Not sure if it was the same bug I found, the problem I read about was that it is a matter of what image effects can be applied to an image.

If you want to use spot colors, a lot of the image effects need to be disabled (because they won't work on images with spot colors). So there has to be some way to let the user choose: Do you want to be able to use the other image effects or do you want the image to stay duo-tone?
Title: Re: spot color images becomes CMYK
Post by: leaf on January 15, 2014, 11:11:27 am
fourth solution yet (but is not free, needful photoshop)
step1  in photoshop prepare Your bitmaps CMYK + spot, if necessary cmyk channels are empty
step 2 save as pdf
step 3 place Your pdf in Scribus in Your project.
step 4 save as pdf (important - embed PDF experimentall)

I attach sample file.
Title: Re: spot color images becomes CMYK
Post by: utnik on January 15, 2014, 11:26:52 am
…it is a matter of what image effects can be applied to an image.

…there has to be some way to let the user choose…

there's no such choice yet – it's one of the reasons why this bug is still open…

utnik
Title: Re: spot color images becomes CMYK
Post by: Nermander on January 15, 2014, 03:48:06 pm
That's what I meant:)

To make it possible to not convert to CMYK there has to be some way for the user to choose.
Title: Re: spot color images becomes CMYK
Post by: mnawij on January 16, 2014, 03:52:06 am
Nermander

The choice is made when a selected spot color is applied to an object.  I am not sure of all the background issues with color programming, but the pdf file type already accepts this within its formatting otherwise Quark, Corel, Photoshop, Illustrator, InDesign would not be able to do it...  Most of these applications can even apply spot colors to Greyscale images, not just single bit b/w images.  I deal with several graphic designers on a monthly basis, and I would say at least 20%+ of the files that I need to print have spot colors applied to bitmaps, but I live in the world of spot color printing.
----------------

Utnik

Thanks for the trick with photoshop-->pdf placement, I will have to give that a try sometime in the next week or so, but my ultimate goal is to use only FOSS software.
Title: Re: spot color images becomes CMYK
Post by: utnik on January 16, 2014, 07:00:17 am
hi mnawij

Utnik

Thanks for the trick with photoshop-->pdf placement…

it wasn't me – you should send the flowers to leaf instead!

utnik
Title: Re: spot color images becomes CMYK
Post by: Nermander on January 16, 2014, 08:23:59 am
The choice is made when a selected spot color is applied to an object. 

That would mean that the code would effectively need disable all non-compatible Image Effects when the user selects a spot color for colorize. Then the user must somehow be informed of this, because otherwise this forum and the mailing list will be flooded with "Why are the Image Effects disabled??"-questions.
Title: Re: spot color images becomes CMYK
Post by: leaf on January 16, 2014, 01:54:19 pm
That would mean that the code would effectively need disable all non-compatible Image Effects when the user selects a spot color for colorize. Then the user must somehow be informed of this, because otherwise this forum and the mailing list will be flooded with "Why are the Image Effects disabled??"-questions.

This is not a problem, "Why are the Image Effects disabled??" it's possible to put any explanation in Scribus Help.
Spot colors don't get in pdf, if there are in bitmaps - it is real problem.
I don't know why spot colors are available in bitmaps effect, if it works only inside Scribus. This is misleading, and dangerous. If any unaware user prepare own pdf file with only one spot color, next Scribus does 4 colors cmyk in pdf, and next print house give a big bill on 4 colors.
So I vote to add full functionality for spot colors, so in pdf, eps too.
Title: Re: spot color images becomes CMYK
Post by: mnawij on January 17, 2014, 01:03:03 am
My suggestion is not to use the Image Effects-->Colorize, I see your point for confusion.  I would make it a separate menu item of 'Apply Spot Color' or such.
Title: Re: spot color images becomes CMYK
Post by: Nermander on January 17, 2014, 09:13:02 am
So I vote to add full functionality for spot colors, so in pdf, eps too.

Scribus will most likely get that. The only question is when. It might come in the next version or it might take a few years. It all depends on how much spare time the developers have to work on Scribus and what features they will prioritize.
Title: Re: spot color images becomes CMYK
Post by: leaf on January 22, 2014, 11:30:10 pm

Thanks for the trick with photoshop-->pdf placement, I will have to give that a try sometime in the next week or so, but my ultimate goal is to use only FOSS software.

Is free solution which works similarly. Needed 3 programs: Scribus, Notepad++, Ghostscript
1. place in Scribus Your photo
2. publish it file as pdf in greyscale mode
3. open your pdf file in notepad++
4 replace 7 0 obj
<<  >>
endobj and paste
7 0 obj
[/Separation/PANTONE#203295#20C/DeviceCMYK<</C0[0.0 0.0 0.0 0.0]/C1[1.0 0.0 0.529999 0.210007]/Domain[0 1]/FunctionType 2/N 1.0/Range[0.0 1.0 0.0 1.0 0.0 1.0 0.0 1.0]>>]

*explanation C1 shows cmyk values to display for example C1[1.0 0.05 0.5 0.0] it is C=100 M=5 Y=50 K=0
PANTONE#203295#20C = PANTONE 3295 C

5. add in 10 0 obj
/ColorSpace 7 0 R
/Decode[1.0 0.0]

/ColorSpace /DeviceGray - delete

You should have
10 0 obj
<<
/Type /XObject
/Subtype /Image
/Width 472
/Height 544
/BitsPerComponent 8
/Length 11 0 R
/Filter /DCTDecode
/ColorSpace 7 0 R
/Decode[1.0 0.0]
>>
endobj


6. save file
7. convert your pdf in pdf in ghostscript (cleans the file = Repair XREF table, in new pdf there are more characters)
Sometimes You can try pdftk and in terminal paste pdftk broken.pdf output fixed.pdf

After this way You have pdf file similar as from photoshop.

I attach sample file.
Title: Re: spot color images becomes CMYK
Post by: leaf on January 24, 2014, 12:24:09 am
I tested solution with edit pdf in notepad++ etc
and I attach sample file, results it works ok, monotone, dutone (combination 2 spot colors, or one spot + black)

For combination colors I use multiply mode in scribus, but is possible to use overprint too.