Like on the leaves above, from time to time I have problems with sun scald on tomato plants, both on the leaves and fruits. This is especially true the last few years as the ozone layer has been thinning over Europe.
One of the things Tom Wagner mentioned when I visited him, was with the new blue tomatoes, the blue pigment reacts to sunlight not only to intensify the blue color, but also to protect the plant against sun scald!
The tomato here was close to the one above, but you can see instead of getting scalded, it’s acquiring blue pigment in the leaves. This is one of Tom’s Helsing Junction Blues tomatoes. The seeds he gave me were F2 or F3, so still very variable. If you’re growing the same tomato, it might look different. Also, I have a few others of the same variety, and they are also different.
To be honest, I hardly bother to grow tomatoes anymore. There are just too many instantly fatal things that can happen with them, the most serious being the blight we get every year. I was interested in trying a blue variety, and I’m also growing one of Tom’s blight resistant Skykomish tomatoes next to it, so the blue variety is sort of acting as a control plant.