dir = getDirectory("Choose a directory");

open (dir+"Ca.tif");

open (dir+"Fe.tif");

open (dir+"P.tif");





run("Merge Channels...", "red=Fe.tif green=P.tif blue=Ca.tif gray=*None* create keep");
run("RGB Color");
saveAs("Tiff", dir+"Fe-P-Ca.tif");

close();
close();
close();
close();
close();

open (dir+"Fe-P-Ca.tif");