Every time you take it out it will start fading until It reaches a neutral limit. If bleaching you will need to get ALL bleach out of fabric otherwise it will keep fading and you will need to bleach it evenly . Plus the bleach could rot the canvas!
I can only tell you my method that is tried and tested. When get to a happy shade the canvas can then be waterproof to lock the colour.
I've seen canvas dyed before now, even painted with water based shed paint to good effect, but it either peels or looks blotchy if not evenly coated.
But always interested to learn.
Don't forget, even if you bleach it, it will still fade naturally.
