CMYK Images that are uploaded are displaying as negatives.
I downloaded the adobe icc color profiles and entered the paths in the settings as described in the documentation without success.
Related
I used Scribus to create a black and white PDF, including images prepared with Gimp. I submitted the PDF to DriveThruRPG for their print on demand service and it was initially rejected by their printer (Lightning Source). This was the feedback from DriveThruRPG:
the interior file had some PDF/X compliance issues. They ran it
through preflight, flattening transparencies, and the resulting file
worked.
For next time, how do I fix this problem on my end? Here is the workflow that I used:
I received images from various sources, opened them in Gimp, converted them to grayscale, and saved them in EPS format. None of the images contained any transparency that I am aware of. Most of the images consisted of black line art on a white background.
In Scribus I created a document, set the Color to Grayscale, laid out the text, imported the EPS images that I had created with Gimp, and exported the document with Compatibility set to PDF/X-1a.
What would it mean to "flatten transparencies" and at what point in the process would I do that? In Gimp? In Scribus?
Edit:
Okay I see that GIMP has a Flatten Image command which removes the alpha channel. Should I try running that on all of the images before saving them in EPS format?
Could Scribus also be introducing transparency into the PDF somewhere? At this link... Is there a way to flatten a .pdf image from the command line? ...I see this command:
pdf2ps orig.pdf - | ps2pdf - flattened.pdf
Should I also run that on the PDF before sending it to the printer?
I'm using Ghostcript to convert some PDF files to JPG. All is working when converting the program consider the resolution of 600dpi when converting and output jpeg quality is good.
Here is my code :
gs -sDEVICE=jpegcmyk -dTextAlphaBits=4 -r600 -dSAFER -dBATCH -dNOPAUSE -o my_output_file.jpg my_input_file.pdf
But when I open the file in Photoshop, the properties contains 72dpi instead of 600dpi I expected :
When I try with RGB profile for output, it is ok, I have got 600dpi.
So what I want is CMYK + 600dpi in image properties.
As can be seen from your screenshots, both images are of the same dimensions, 6803 by 709 pixels.
And that is all that matters.
Also, the size of the CMYK version is bigger by about 33% compared to the RGB version -- as is to be expected for an image with 4 color channels instead of 3.
Ghostscript used the -r600 CLI parameter to correctly expand the number of pixels when converting the PDF file.
Ghostscript does not add any EXIF metadata to its output when converting a PDF to raster.
The DPI or PPI information would be an internal metadata hint to tell any compliant viewers how big to render the image on screen. It would not change anything substantial in the image information itself.
Why Photoshop does think it should use 72 dpi for one, but 600 dpi for the other, you may ask Adobe about.
I bet Photoshop also renders the 72dpi file about 7 times larger on screen than the other. Is that the case?
P.S.: See also "What DPI do web images need to be?"
I see extrem colour changes on tif files converted to jpg/png.
Try this:
http://files2.hanser.de/Files/Article/ARTK_CT1_9783446247246_0001.tif?scale=both&format=jpg&decoder=freeimage&quality=80&height=2000
for a the wrong Colour, it appears green while the tiff itself is tourquise.
You can download the original tif from the same address.
I tried with all kinds of Settings, ignoreicc, with and without freeimage Decoder, jpg vs. png, etc. - no Change of appearance.
What to do ?
Thanks.
I looked into your situation and found several CMYK related bugs in old patch notes for the freeimage decoder. The TIF you are providing has a CMYK color profile. They have since been fixed. Removing the freeimage decode tag produced the desired result. Is your imageresizer core and freeimage plugin up to date?
http://files2.hanser.de/Files/Article/ARTK_CT1_9783446247246_0001.tif?scale=both&format=jpg&quality=80&height=2000
Produces
A resulting JPG with the correct colors
You can reduce color shift when converting CMYK to RGB if your server's display profile is set to sRGB.
.NET's System.Drawing is designed exclusively for display purposes, and targets your server's current ICC profile, which is not always sRGB.
We hope (assuming sufficient funding), to eliminate both FreeImage and System.Drawing in a future version of ImageResizer, which will give us the control required to have perfectly accurate colorspace conversions.
https://github.com/imazen/imageflow
I'm working with PDFClown and I'm trying to extract images from a pdf file. I use the example code provided by the source code that can be found at http://pdfclown.org.
ImageExtractionSample.java.
The problem is the images are negative and flipped horizontally. Does anyone know how to resolve this problem?
Check with other PDF files to see if other PDF files are also giving the rotated or flipped images. ImageExtractionSample.java is not checking rotation or matrix defined transformations for the image object but just writes the content to a file as is (so it will work for JPG images but not for CCIT encoded images for example).
So there are things to consider when you extract image from PDF:
image can be rotated using the attached transformation matrix (CTM);
image can be rotated/transformed as part of the form which is transformed;
image can be placed without transformation on a page but the page itself is rotated;
image may contain the overlaid Mask on top of it (and the Mask can be rotated and transformed);
JPG image is stored pretty much as is but there are other formats supported by PDF like CCIT compression, LZW compressed images etc;
But the general suggestion is that when you extract JPG image from PDF using PDFClown you should just flip and rotate extracted images like suggested on the SourceForge project discussion page.
if you could point to the particular PDF sample file then it would be easier to suggest the solution.
If you're on Windows then you may use this free PDF Multitool utility to compare non-transformed and transformed images from PDF using "Extract raw images (without transformation)" option in images extraction dialog.
Disclaimer: I work for ByteScout, the PDF Multitool utility is free for both commercial and non-commercial purposes.
I'm converting PDF to JPG with gs.
Does gs substitute embedded fonts? How exactly this works? Like if i embed all fonts that is used in PDF does gs still look for some substitution or can it use that embedded font data?
So does embedding fonts in PDF mean that all glyphs used in PDF with that font is being embedded and i don't need to have that font in my gs font path?
Thanks!
When you’re outputting a JPEG file, you’re in effect outputting an image. This means that Ghostscript renders the page as image, then compresses the image using JPEG (lossy – to prevent reduced legibility of the text, use a lossless compression format such as PNG instead; JPEG is basically only good for photography because lossless would be much too big there).
In a bitmap image, there are no fonts, only pixels – so, for text rendering (e.g. black text on a white page), Ghostscript will create a bitmap image consisting only of greyscale pixels (by means of anti-aliasing), then save that.
To be able to do that, Ghostscript must have access to the fonts at the time of PDF rendering and JPEG creation. This means that the fonts either must be installed on the system (and in your font path), or embedded in the PDF in the first place. They are not necessary to view the JPEG file.