// This macro changes an image's display gamma // c'(i) = 255 * (c(i)/255)^gamma) // It does this by remapping the LUT, which // preserves the pixel values, unlike the // built-in Process>Math>Gamma function, which // remaps the pixel values. Use Image>Color>Show LUT // to view the resulting Gamma function. var gamma = 1; macro "Gamma [F1]" { getLut(r, g, b); gamma = getNumber("Gamma (0.1-5.0):", gamma); for (i=0; i<256; i++) { r[i] = pow(r[i]/255, gamma)*255; } setLut(r, r, r); } macro "Reset Gamma [F2]" { getLut(r, g, b); for (i=0; i<256; i++) { r[i]=i; } setLut(r, r, r); } macro "Show LUT" { run("Show LUT"); }