How do I use Gimp / OpenCV Color to separate images into coloured RGB layers?
In the BGR image, you have three channel. When you split the channel using the split() function, like B,G,R=cv2.split(img), then B,G,R becomes a single or monochannel image. So you need to add two extra channel with zeros to make it 3 channel image but activated for a specific color channel.
I have a JPG image, and I would like to find a way to:

Decompose the image into red, green and blue intensity layers (8 bit per channel).
Colorise each of these now 'grayscale' images with its appropriate color
Produce 3 output images in appropriate color, of each channel.

For example if I have an image:
dog.jpg
I want to produce:
dog_blue.jpg dog_red.jpg and dog_green.jpg
I do not want grayscale images for each channel. I want each image to be represented by its correct color.
I have managed to use the decompose function in gimp to get the layers, but each one is grayscale and I can't seem to add color to it.
I am currently using OpenCV and Python bindings for other projects so any suitable code that side may be useful if it is not easy to do with gimp