I recently had a similar problem, in my case due to forgetting to uninstall Xposed Framework before the OTA (details here).
I solved it by manually installing the OTA (as described here, scenario 1), which allowed me to see the exact error which ...
Any chance of a photo at 50% brightness for comparison?
There you go:
I'm not sure what else it could be atm. Is it only noticeable on a white screen or can you see it on other colours too?
I first noticed it ...
take a look at Spirit FM Radio
take a look at Call Logs Backup & Restore, it's free and it works like a charm
this author also has free apps to backup SMS and APNs...