I am using Scribus 1.4.3. on Lubuntu Linux 13.10. I have scoured the net trying to find anything related this topic, with no success so far. Let's say I:
1. import a bitmap image into Inkscape;
2. produce an svg file by tracing it in Inkscape;
3. create a document in Scribus;
4. import the svg file into the new document;
4. call the Preflight Verifier.
Oftentimes the Preflight Verifier will warn me that the file has less than 144 dpi. Reducing the svg frame size within Scribus will eventually suppress the warning; enlarging it will eventually cause the warning to be issued. This apparently does not happen with svg files that have been created directly with Inkscape. I find this puzzling, because an svg file should not cause dpi problems, unless a bitmap image has been embedded into it - which is not the case, as far as I know, because tracing has been used.
An example is shown in the attachments. The original bitmap file was an jpg, which was cleaned, sharpened and exported as princeto.png, by means of Gimp 2.8. This was then imported into Inkscape 0.48, traced with the Color option on and Smooth option off and the remaining options at their default values. This svg will produce the low-dpi warning described above. Reducing the heigh and width of the svg-frame simultaneously will eventually suppress the warning.
I wonder whether I should really pay any attention to this when preparing pdf files for printing. If so, what would be the solution?
Thank you for your help.
Francisco S. Wechsler