Plotting Raster images: "Processing Image" repeats on and on

I have drawings with MRSid raster images (aerial photos). When I plot to DWF
or laser printers, autocad gets bogged down with processing the images
during the output. There is a constant stream of progress bars saying "Image
processing", and the plots take forever to complete. What does this iamage
processing mean and why is it so slow for certain printers?

 

I am plotting a map of the city with aerial photos as a background. There
are 4 grayscale photos in MRSID format of about 18 megabytes in size each.
Output is to an HP Laserjet 8150 network printer as well as the DWF writer.
(I am the one that posted the question about high resolution plots to DWF in
the DWF forum). When plotting to DWF using DWF Writer (I have the resolution
set to 1200x1200 DPI) I tried plotting a small area of the map (About 2 city
blocks, with parcel oultines) to an 11x17 size sheet. The image processing
progress dialogue ran for several minutes. The output file was 10 Megabytes
in size and when I tried to load it using expressviewer I never could get
the image to show. I closed the viewer and tried to delete the file, but
could not delete it because the system said it was in use. I ended up having
to kill autocad and express viewer and restart my computer.

I experienced the same lengthy image processing when sending a plot to a
MITA color laser printer that we were trying.

 

You are right about the huge spool files. That was the main reason we gave
up on getting the color laser. I don't want to use plot files if I can help
it because they ultimately end up getting left on the drive and taking up
disk space. I was thinking that the long image processing was due to the
image file compression algorythms but apparently that is not the case.

 

First, try lowering your printing resolution 1200x is a bit high (I'm assuming your plotting 24x36 or similar). Unless you have gigs of ram, you will not get that and I'll bet that you won't notice it anyway. Try going into Map\Options\Image Defaults and dropping the Density setting from 300 to 150, I honestly can not tell the difference when plotting at 600dpi, and my plot times are drastically reduced. Second, consider that an 18 meg sid file is compressed 80-90%, that means that 18 meg file when decompressed is well over 100 megs X however many images are in your drawing. Thats why when you plot it takes so long, Map has to scan strips to spoole.
Good luck

-Newton

 

I will try adjusting the image densities for plots as you suggest. However,
for DWF I want high resolution for viewing so I won't adjust.

assuming your plotting 24x36 or similar). Unless you have gigs of ram, you
will not get that and I'll bet that you won't notice it anyway. Try going
into Map\Options\Image Defaults and dropping the Density setting from 300 to
150, I honestly can not tell the difference when plotting at 600dpi, and my
plot times are drastically reduced. Second, consider that an 18 meg sid file
is compressed 80-90%, that means that 18 meg file when decompressed is well
over 100 megs X however many images are in your drawing. Thats why when you
plot it takes so long, Map has to scan strips to spoole.