File Size When Plotting with Ortho Photos

[Anonymous]

I am plotting 24x36 dwgs at 1:500 with an ortho photo as a background. The original ortho photo was a 250MB .ecw file. I converted this file to .tiff (it ballooned up to 653MB). Then cropped the TIFF down to the area I was working in (126MB). Long story short it is now an 8MB JPG.

Here's my question: The area I am plotting is only 10% of the entire cropped JPG. Yet when I plot to DWF the DWF file size is 14-18MB +/-. I have reduce all the raster resolutions down to 150DPI and reduced the color depth to 24bit. So why does the file size shoot up when I'm only plotting a small portion of the ortho?

[Anonymous]

Probably because it's ending up as a png in the DWF then which isn't the
best compression if it's a monochrome file. Also in the DWF pc3 there is a
Raster DPI setting. So your 8 MB jpg at 96 dpi is probably being converted
to a 200 or 400 dpi image depending on what the setting is. So going from
96 to 200 dpi is going to make the image size go up 4 times.

If it's a monochrome image convert it to a group 4 tiff file and try that in
AutoCAD instead.

--
Rodney McManamy
President
CADzation
CAD to PDF and DWF Solutions for Architects and Engineers
rmcmanamy@cadzation.com
http://www.cadzation.com
wrote in message news:5521600@discussion.autodesk.com...
I am plotting 24x36 dwgs at 1:500 with an ortho photo as a background. The
original ortho photo was a 250MB .ecw file. I converted this file to .tiff
(it ballooned up to 653MB). Then cropped the TIFF down to the area I was
working in (126MB). Long story short it is now an 8MB JPG.

Here's my question: The area I am plotting is only 10% of the entire cropped
JPG. Yet when I plot to DWF the DWF file size is 14-18MB +/-. I have
reduce all the raster resolutions down to 150DPI and reduced the color depth
to 24bit. So why does the file size shoot up when I'm only plotting a small
portion of the ortho?