Plot DWG to PDF: How to set jpg compression quality?

[cupax]

Hello,

We plot a lot using DWG to PDF plotter. While it plots vectors perfectly, our inserted bitmap (jpg) files always plot with a very bad quality - the plotter compresses the jpg too much. I'm not talking about resolution (you can easily set it in the plot dialog) but about jpg compression ratio (for ex. in Photoshop it is found in the save dialog - a slider between 0 and 100).

Example: Our original jpg file is about 1.3Mb in size, the plotted PDF file comes out barely 250Kb. This shows the too strong compression.

Does Autocad have anything to set jpg compression while plotting? 

Attached is the original jpg vs plotted jpg.

Thanks.

[pendean]

You will need to find a 3rd party PDF driver that better meets your needs, you cannot edit the Autodesk provided drivers like that.

[cupax]

Too bad.

Do you know any PDF printers that would have this (jpg) functionality while being able to print lines and fonts as vectors?

All the "free" ones just convert lines to raster image - not very useful.

[pendean]

You will need to explore the support/user forums for Adobe Acrobat Pro and BlueBeam to name a few and ask about the ability to control downsampling of raster images. No freebies are going to do it as far as I know.

We use Adobe Illustrator (or Photoshop) when we need to re-print images in top quality, AutoCAD is not a great tool for the task and we use it sparingly.

FWIW jpg is about the worst image format if you want loss-less reproductions: PNG is way better, High res TIFF files are even better. The better wuality your image starts off with the better your printing results too.

[cupax]

Hi,

I've tested a variety of PDF plotters and found out, that all plot lines rasterized.

If you disable the "Plot with Transparencies" in the print dialog the lines plot as vectors but then you lose the transparencies in the drawing, so this is not a 100% good solution.

I think still the best PDF plotter is Autocad's integrated DWG to PDF but the driver badly needs an option of bitmap compression.

[pendean]

We never use "Plot with Transparencies" as it tends to add a lot of issues.
If you use plot style tables, rely more on DRAWORDER and pen settings that are less than 100% ink and you'll get the same effect.