strange printer behaviour with eagle

[Dan Moos]

I created a PCB layout in eagle, and it looks fine on the print preview.

I print it out, and instead of my traces curving as they should, it appeared as a collection of rectangles that followed the path of my cirtcuit. Imagine if you needed to draw the circuit but all you hade were individual squares the width of the trace to work with, and imagine what the corners would look like, and you get the idea.

Gets weirder. I printed to .pdf, and the .pdf looked great. Printed the .pdf from the adobe viewer, and got the same wrong results. This makes me think that its being printed as some sort of vector drawing instead of a bitmap, and the driver isn't getting it right.

Next clue, if I open the .pdf in photoshop, I can print it with good result. That sorta confirms my theory I think, as I'm sure photoshop turns it right into a bitmap. I guess that's a solution of sorts, but I really want to eliminate the extra step.

My printer is a DELL 1720dn I was given for free. I am using windows 8 (ugh). Any thoughts?

 

[pinkmouse]

I suspect your printer driver. Has it been updated for W8?

 

[JMFahey]

*or* you (or the software) set print resolution to 72 DPI .

For some unfathomable reason, some programs consider 72 DPI "screen resolution" , (probably was correct in the 16 colour, 640x480 VGA days), and a few old ones offer it as *printer* resolution (which I haven't seen for around 20 years).

Even if your printer is capable of 1200 x 1200 DPI resolution, if you *order* it to, it will faithfully generate very raw looking 72 DPI squares ... made out of much finer , invisible dots.

Going through Photoshop seems to bypass that.

Check the printer setup or export options in Eagle, I guess you'll find the culprit there.

Or printer properties in Windows Control Panel .

 

[Dan Moos]

hmmm, that sounds like it would be a strong possibility, except in Eagle, I was indeed set for 1200 dpi. Also, when I printed to .pdf, it came out fine on the screen, making me think it was indeed "printing" at the proper resolution. Print preview also looked fine

Is there any way to know if eagle and my adobe .pdf viewer create vector images rather than bitmaps? That's what I was wondering might be why photoshop didn't hgave an issue. I gave photo shop the same .pdf that printed wrong and it printed fine, so it was exported properly from eagle. I do think this could be a driver issue, but its an old printer and I believe the drivers are current, but haven't been updated since windows vista times.