raster colour

[nchome]

Can anybody please help with the following?
I am trying to make part of a raster image (Tiff), green with the following method.

1 - Create a new green layer
2 - Create a REM of the objects i want green and put them on green layer.
3 - Convert the REM back to the raster image.
I now have a raster which is part green and the rest black.
When i plot this drawing everything is fine but if i close autocad down and reopen the drawing the preview looks fine but when the drawing opens the green parts have changed back to black.
How do i keep the green parts green when i reopen the drawing?

Many thanks in advance for replies

[Railrose]

The only way to change a bitonal image color in an area that I know of is to make a new image & merge the REM area to it, & set it with a different color.

[david.zavislan]

Change the image color depth to TrueColor

Draw a close polyline around the region that you want to make green.

Run the Histogram command, Use the 'Existing' option to select the closed polyline.

On the Brightness/Contrast tab, Change the histogram from RGB to Green,

Increase the brightness.

Click Apply.

Finish by writing the updated image to a new file. Maintain the link to the new file.