Mike Chaney's Tech Corner

Mike's Software => Qimage Ultimate => Topic started by: Ernst Dinkla on June 02, 2016, 08:25:15 PM



Title: Converted PDF issue
Post by: Ernst Dinkla on June 02, 2016, 08:25:15 PM
Not new and there is a solution but I still wonder what causes it.

I have some PDFs from a customer, large sizes this time. I convert them to JPGs with Photoshop CC, 300 PPI, RGB. I know there are CMYK vector and font colors in that PDF but this time only black, the images are in RGB. Save the JPGs and load them in Qimage. First one appears with an error thumb like happens with CMYK files. Save that one again an no error.They are refused for one reason or another. Take them to Photoshop CS 5.1 and save them again. Still refused. Take them to Photoline and save again as JPG and Qimage accepts them. This route has been used more often.

JPGs in CMYK do not exist as far as I know so I would not expect a hint in them about the CMYK color description of the original PDF. I use JPG as there is a lot of white in the design so the size becomes way smaller than with a Tiff. Is there a save or export setting in Photoshop for JPG I should pay attention to?

Met vriendelijke groet, Ernst

http://www.pigment-print.com/spectralplots/spectrumviz_1.htm
January 2016 update, 700+ inkjet media white spectral plots


Title: Re: Converted PDF issue
Post by: admin on June 03, 2016, 12:09:26 PM
Ernst,

CMYK JPEG's are likely the problem.  They do exist and if you have CMYK metadata in the PDF, the JPEG may save in CMYK color space:

https://en.wikipedia.org/wiki/File:Channel_digital_image_CMYK_color.jpg

I'm not sure what the solution might be in PS.  Maybe try converting to sRGB color space prior to saving?

Regards,
Mike


Title: Re: Converted PDF issue
Post by: Ernst Dinkla on June 03, 2016, 09:12:54 PM
Mike,

The color settings in Photoshop had sRGB as the color space for RGB. When a PDF is imported and rasterized you have a choice to use either RGB or CMYK. I selected RGB and the file will then get sRGB assigned when saved as a JPG. There may be some CMYK references in the RGB JPG without any function that may have triggered Qimage's attention. Pulling it through Photoline may have stripped the CMYK part, it worked at least for one file printed through Qimage.

One of the JPGs had another flaw I hadn't noticed so far. This is a PDF design close to 5 meters in length and in the Photoshop CC rasterization the length was compressed to 60%, not the width. I could not get that right either. Asked my customer to export a JPG from Illustrator where she made the design and it also resulted in a length compression. Then she decided to export a Tiff and this time the length was correct. This issue happened within Adobe applications....

I have to check whether Acrobat can load similar files and find a print to file app with JPG or Tiff output that could solve this issue. The beauty of PDF conversions to pixels within Adobe software is that you do not get font substitution issues or a need for yet another range of fonts.

Met vriendelijke groet, Ernst

http://www.pigment-print.com/spectralplots/spectrumviz_1.htm
January 2016 update, 700+ inkjet media white spectral plots