Color Change

I was looking at my plants last night as I watered them and noticed a few of the tomatoes are starting to show some color change. I think I might have some red tomatoes soon.
The ones I already harvested are starting to show some color changes as well. I was very excited with I saw them this morning and noticed they were changing.
Now the ones outside are only showing a yellowish color but the one inside is actually got a reddish tint to it. As usual please check out the pics below...