Adobe printing bitmapped graphics funny?

Question

I have a PDF with some fairly low resolution bitmap graphics in it. It looks fine on screen, but prints way worse than the bitmap should. The output looks like it's printing a 75 DPI bitmap at 100 DPI, no upsampling, no antialiasing, only doubling lines every so often. As this is a schematic, actual one-pixel width lines vary from 1 to 2 pixels wide and text looks horrible.

On the very same page, vector graphics are rendered at high resolution, and a few pages over, high resolution bitmaps render properly (or more likely, they're being stretched the same way, but I can't see it at that resolution).

When the images themselves are printed (e.g. from Firefox or Windows Paint), they come out fine. I'm pretty sure it's an Adobe Reader thing. The question is why, and how do I make it behave?

I would hate to have the only solution be resample the bitmaps. I'm thinking stretching the schematics by a factor of 6 will make them print correctly. But this is an ugly solution to a problem that shouldn't exist!

Tim

Polyp · Accepted Answer

I know SFA about what the problem is, however I have had similar problems printing schematics / dwgs and have got around the problem by selecting "print as image" in the print options.HTH.

Robert Baer · Answer

Adobe "invented" vector graphics: PostScript - which is included as a part of the Acrobat "engine", so that is why vector graphics are so good. I think that other graphics are converted to JPEG internally at (am guessing wildly) 20 percent compression, thereby adding the visible trash during output. And i suppose that you know about moire patterns and how they show as the angle of the two dot patterns are changed.

JosephKK · Answer

upsampling,=20=20and=20likely,=20Paint),=20=20exist!I suspect that this is related to the file format that the graphic isstored in.  Try various file format conversions and se what happens.--=20Transmitted with recycled bits.Damnly my frank, I don't give a dear----------

Tim Williams · Answer

Thanks, that works for now.I'd still like to know if there's something I can do with default settings, though.Tim-- Deep Friar: a very philosophical monk.Website:

Tim Williams · Answer

No, it's not JPEG artifacts, it's a lot more like, well, Moire.

It's like Moire, but at no angle, just a different grid size. So like, three lines are original scale, then one's doubled up. Repeat in X and Y directions for the whole image.

Tim

Tim Williams · Answer

Well, it starts out as PNG. Damned if I know the internal format after it's chugged away. I can only start from a few formats, since pdflatex only supports those.

Tim

JosephKK · Answer

It=20The=20upsampling,=20and=20resolution, and=20likely,=20Paint),=20print=20exist!=20good.No.  Vector graphics predate the oscilloscope in its most primitiveform.  Indeed it is the very basis of engineering drawings.  Languagedefinitions and tutorials for PDF and PostScript are available forfree from Adobe on their web site.PostScript fonts is all about characters defined as outline and fill,the rest of it is rasterization and a graphics definition and pagelayout language.  But if you are really interested ask Don Lancaster.Images are generally handled as some source decoded into a bitmap,cropped, and inserted at the specified location.  It is possible towrite some pretty impressive image manipulation tricks in PostScript.=20

JosephKK · Answer

it's=20You might try conversion to either jpeg or svg depending on content.What does pdflatex handle?

Tim Williams · Answer

JPG, PNG and PDF. Printing to PDF I'm guessing ends up with the same problem (although it probably depends on what you use), and JPEG is suboptimal for monochrome line drawings.

Tim

Adobe printing bitmapped graphics funny?

Join the Discussion

Didn't find your answer?