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Author Topic: Exporting 1bit line art to pdf....  (Read 4659 times)

ragtag

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Exporting 1bit line art to pdf....
« on: July 07, 2011, 01:50:20 pm »
I just got the proof of my comic back from the printer, and it seems I've messed up the exporting a bit. All the line art is a bit dotty or hairy, which makes me think i may have exported it as grayscale, and the book printer is rasterizing it. All the text is fine, so it's not the printing itself.

The drawings are all clear black and white line art, so I only really need 1bit of information. The images I've imported into Scribus, are full color rgba (32bit) though, as I needed transparency to make page numbers show through (there's probably a better way to do this).

Is there a way to export to PDF from Scribus, so that there is no grayscale? Just pure black or pure white.
And is there a good way to check this before sending it off to the printers?



p.s. The white area of the images covers the page numbers, which is why the images have transparency. I could batch convert all the images to 1 bit color, but then they would cover the page numbers which are on the Master page. Is there a way to put the Master pages on top of the actual pages, rather than behind?

ragtag

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Re: Exporting 1bit line art to pdf....
« Reply #1 on: July 07, 2011, 11:57:23 pm »
I'm a bit closer to a solution here, but not within Scribus.

First of, it seems that since I was doing downscaling in Scribus to 300dpi (which should have been 600dpi anyway), the images were being anti-aliased. The anti-aliasing was then getting made into raster during the printing, making the lines look fuzzy or dotted.

I think I've now found a somewhat convoluted solution using Ghostscript, that seems to work (won't get a new proof print for a week, but zoomed in in Acrobat Reader with all image smoothing off, it looks correct). It's basically three steps:

1. Export from Scribus as PDF at full resolution (most of the drawings are between 600dpi and 1200dpi).
2. Convert to PostScript file at full resolution, but using monochromatic 1 bit images.
Code: [Select]
pdf2ps -dAntiAliasMonoImages=false -dDownsampleMonoImages=false -dMonoImageDepth=1 original.pdf intermediary.ps3. Convert to pdf while downscaling the images using bilinear filtering.
Code: [Select]
ps2pdf -dAntiAliasMonoImages=false -dDownsampleMonoImages=true -dMonoImageDepth=1 -dMonoImageDownsampleThreshold=1 -dMonoImageResolution=600 -dMonoImageDownsampleType=2 -dDownsampleGrayImages=true -dGrayImageDepth=1 -dGrayImageDownsampleThreshold=1 -dGrayImageDownsampleType=2 -dGrayImageResolution=600 -dDownsampleColorImages=true -dColorImageDepth=1 -dColorImageDownsampleThreshold=1 -dColorImageDownsampleType=2 -dColorImageResolution=600 intermediate.ps final.pdf
Note, that this would only work for 1bit monochromatic images (line art), and would probably mess up your photos.

While the result isn't 100% identical, as the images are being scaled down, the bilinear filtering (DownsampleType=2) seems to do an ok job of it.

If anyone has a better solution, then please let me know. The exporting and conversion steps actually takes quite some time, so I wouldn't mind having a way to speed reduce it to just one step. :)
« Last Edit: July 08, 2011, 01:15:55 am by ragtag »

a.l.e

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Re: Exporting 1bit line art to pdf....
« Reply #2 on: July 13, 2011, 02:32:16 pm »
are you using hairline lines?

1pt is the minimum for a correct printed result...

but i'm just guessing...

ciao
a.l.e

WalksIn2Trees

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Re: Exporting 1bit line art to pdf....
« Reply #3 on: September 09, 2011, 01:18:59 am »
This is probably resolved one way or another by now, but:

@a.l.e:  1 bit refers to color depth not line width...meaning that he just wants black pixel data in the output

@ragtag: Scribus can put the folios on top of your images, just make sure the master page containing the folio is on top

300 ppi at print size is the printing industry standard for images that will be half-toned... that's why it's the default

whatever they use might scale down the image resolution to 300 again, so be sure to be sure to confer with them about what exactly you should submit before you go through a lot of work....

with Photoshop or Photopaint you can run a Median Filter on each image to clean up your lines, just fine-tune it before you start, and check each image carefully as you go not sure what the filter in Gimp might be

aa_gangchen

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Re: Exporting 1bit line art to pdf....
« Reply #4 on: September 17, 2011, 07:26:51 pm »
I have figure out a way to do 99% of the work in Scribus, and then for teh remaining 1%, you can go to FedEx/ Kinko store to rent a computer for about 5 or 10 minutes at 0.30USD per minutes (that is a total of 1.5 USD to 3 USD) to easily convert the file to PDF X/1-a:2001 format.

No special technical knowledge is necessary.

See detailed discussion in my book, Using FREE Scribus Software to Create Professional Presentations: Book Covers, Magazine Covers, Graphic Designs, Posters, Newsletters, Renderings, and More (Full Color Edition)

ISBN: 9780984374151   

See the following link:

http://www.amazon.com/Scribus-Software-Create-Professional-Presentations/dp/0984374159%3FSubscriptionId%3D1QZMGW0RRJC2PX87HDR2%26tag%3Dsalranexp

utnik

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Re: Exporting 1bit line art to pdf....
« Reply #5 on: September 18, 2011, 01:02:08 am »
hey, gangchen – your ad for the book has no direct connection to this thread!!!
if the solution for this one-bit-story would be a pdf/x-1a, this could be produced for free with scribus 1.5.0svn (experimental) without the need of a commercial software (and your commercial manual…)

utnik

 

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