Adobe printing bitmapped graphics funny?

[Tim Williams]

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]

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

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.

 

[Tim Williams]

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.

Thanks, that works for now.

I'd still like to know if there's something I can do with default settings,
though.

Tim

 

[Tim Williams]

I think that other graphics are converted to JPEG internally at (am
guessing wildly) 20 percent compression, thereby adding the visible trash
during output.

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

And i suppose that you know about moire patterns and how they show as
the angle of the two dot patterns are changed.

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]

I suspect that this is related to the file format that the graphic is
stored in. Try various file format conversions and se what happens.

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

 

[Tim Williams]

You might try conversion to either jpeg or svg depending on content.
What does pdflatex handle?

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