How to convert the white component of binary image into an RGB image?

This is my code. I want to convert my code final value into original image which is RGB, but the selected one which I separate at the end of my code. Here is my code:

I = imread('D:\seven semester\DIP\lab2\Image Data\N10.png');
figure;
imshow(I);

G = rgb2gray(I);
% figure;
% imshow(G);
A = I(:,:,1);
% figure;
% imshow(A);
F=imsubtract(A,G);
F= im2bw(F,0.18);
figure;
imshow(F);

Thanks for helping

[Image Analyst]

I can't understand what you want to do. Why would you want to convert a binary image into a color binary image? Are you thinking of label2rgb() perhaps? That works on a labeled image. Or do you want to do masking where inside or outside the mask is black or white???