Good day Amy,
your problem needs an individual solution.
If you've read the short section about false color and perhaps a bit more about LUTs, you should realize that you need a custom LUT that gets you from the color LUT to a reasonable gray LUT.
After having studied the manual, you should be able to convert the present color LUT to a reasonable gray LUT. The tools are provided by ImageJ. Getting a useful LUT for the conversion may take a while (of thinking and doing) …
i'd begin by looking at the present color LUT:
- Open your image in ImageJ
- "Image > Color > Show LUT"
- In the then opening dialog click on "List..."
- Save the LUT-list as text file
Then I'd modify a copy of the color LUT:
- Save a copy of the LUT-list and open it in a text editor
- In the text editor, modify the copy to contain reasonable gray values
- Gray values have the same value for Red, Green and Blue