RGB image is composed of three color channels. This script decomposes those channels into own variables and displays them as grayscale images.
A = imread('kytka256.jpg'); R=A(:,:,1); G=A(:,:,2); B=A(:,:,3); subplot 221;imshow(A);title('Original'); subplot 222;imshow(R);title('Red'); subplot 223;imshow(G);title('Green'); subplot 224;imshow(B);title('Blue');
Something is wrong? Let us know right here