I am red/green color blind. In your opinion is this really going to handicap my restoring ability? Maybe I should work with black/white only?
Very interesting question. I can only answer it from my own experience. I used to know someone in art school who was color blind. I remember, they made us go out and buy a big box of color cards, hundreds of them, about 4×6 in size, and each card was a the tiniest bit different from the last. While I could easily see how each card was different, this other student could not tell the difference at all. In the context of "would he be a bad designer", of course not. However, he failed that assignment, because he was unable to complete it.
About me: A few years ago I noticed something very unsual about my eye sight. In fact, you can play along, and see how you do. Look at a solid surface, preferably white. Table, wall, whatever. Now put your had flat against your forehead, run your wrist down your nose, between your eyes so that your view is split between the left and right. Dont over think it, if you dont understand specifically, the point is to just split your vision between your left eye and right eye. Now… when I focus, and look out of my left eye, it has a blue color cast. When I look out of my right eye, I see a clearly red color cast. Why? I have no idea why my two eyes see two different colors. But when put together, I see the color just fine.
I also knew someone who was painting a picture of a cat, and the cat looked grey to him, and purple to the rest of us.
Back to the original question. I just gave three different color difficulties. I do not know how much of an impact that will play on your retouching ability. If I had to guess, you could likely retouch quite happily, in less professional situations. Color matching is likely going to be hard for you, if you are given a picture of a blue sweater, and a green sweater, and told to better match the green one. You would also have difficulty where the cover of a magazine needs less red in the flesh tones. This may also be a situation where you just can't tell the difference, thus unable to perform the task you are expected to.
In the end, I think an honest answer is that if you want to do it for fun and a hobby, then go for it. However, a professional situation may not be best for you. While there is plenty of work to be done to a black and white image, you would be limited in your creative scope. Almost limiting you to restoration of old black and white photographs. But, if this is what you are looking to do, then nothing wrong with that.
I believe that maybe you could sit down with someone else, and use color sliders on an image, and get an understanding of where your limitations lie. I cant see 2 or 3% moves, but I can see 4%. Maybe you are limited to 10%… or is it 20%? The larger the gap, the harder it will be for you. But, you shouldn't let a handicap get in your way, if you really want to enjoy doing it. Just, take some time to learn your limitations, and try to work around it.