Em,

The tomatoes are a darker green earlier in their life. As they begin to turn from unripe to a more ripened stage, they turn pale green, then greenish-white and then almost white. Then, if they are red tomatoes for instance, you start seeing the first appearance (blush) of pale pink appearing on the whitish tomato and then it gradually turns red. With a yellow or orange tomato, you see a blush of color that is more yellowish-white or orangeish-white at first blush. With Cherokee purple, they are darker than pink, but not really purple at that blush stage.

My best guess is that the above is what you're seeing.

Sunscald is also a possibility if the fruit are not heavily shaded by foliage.

There's also a condition called graywall that can occur when certain difficult weather conditions and/or soil/fertility issues occur. With graywall, a tomato will not ripen normally and you may see some blotchy ripening, often with yellowish to yellowish-grayish patches. Gray wall develops under a variety of challenging conditions, including high humidity, temperature fluctuations, high soil moisture, high nitrogen, low potassium, compacted soil, low light intensity and, perhaps, the involvement of certain fungi and/or infection with the virus that causes tomato mosaic. You don't have to have all the above to have graywall, just some of them.

I'm going to link the now-familiar Tomato Truss Timeline. Look at about the difference between Day 34 and Day 49 to see how a tomato gets slightly lighter as it nears the point where ripening will become apparent. It is not necessarily as much of a change in these photos as what I observe here in real life. Here, at about the same stage shown in the photo from Day 49, I often see fruit that is very light, lighter than in the photo and when I see that, I know that the first blush of the fruit's ripe color will be appearing shortly.

Dawn

Here is a link that might be useful: Tomato Truss Timeline