For page layout programs, you use a clipping path, but that is
all-or-nothing transparency, no translucency.
If AutoCAD supports an 8-bit alpha channel for defining 256 levels of
transparency, then you just need to know what file format it accepts.
There are several ways to create an alpha channel in PS. If you need
an area to be 30% opaque, then one way would be to:
1. Create a new alpha channel in the Channels palette by clicking on
the "Create new channel" button. Depending on how you have things set
up, it will either be all black, or all white. You can double-click
the channel and change the "Color Indicates" option if you want.
Black "pixels" in an alpha channel, will mask out corresponding pixels
in the image, so the new channel filled with black, if used as a mask,
would hide everything. If you want the mask to reveal everything, just
fill the alpha channel with white.
2. Select the area in the image you want to be translucent using
whatever tool(s) or technique(s) would be appropriate. If you want the
whole image, just Select>All, or Ctrl-A.
3. With the selection active, fill the alpha channel with 70% gray.
(You'll first need to click on the channel in the palette.) That will
make the area 70% transparent (or 30% opaque) if the alpha channel is
used as a mask.
4. Save as TIF, and make sure "Alpha channels" is checked in the
5. Open the TIF in AutoCAD. You'll need to look up how to apply the
alpha channel in that app, as it may not use it automatically.
>> > I want to save a tiff with a translucent alpha channel mask
>> > for use in AutoCAD. Is this possible to make the image
>> > translucent by erasing with a 30% opacity or even a halftone
>> > pattern to make it see-through? If I do the translucent
>> > erase, it doesn't help.
>> Make the alpha mask a lighter grey instead of Black.
>Hmmm, So this should work for placing art in illustrator or quark?
>It doesn't seem to show up in autoCAD which doesn't suprise me. It
>seems the deleting the foreground is necessary to have any impact
>or else it all shows as white... Does that even make sense? It
>doesn't quite to me. Maybe I don't understand how masks work.