Converting colours and black background removal

Question

enter image description hereI have an 8-bit black and white image and want to convert the few black spots to blue on a white background.

When I use Image->Lookup Tables->blue it creates a black background that I am unable to remove. Any better solutions hugely appreciated

Answer 1

If you don't mind a resulting RGB-image, i.e. no LUT-colouring, then the following ImageJ macro code should work:

//
setOption("BlackBackground",true);
run("Convert to Mask");
run("Create Selection");
setForegroundColor(255,255,0);
run("RGB Color");
run("Fill","slice");
run("Select None");
run("Invert");
//