iOS 7.0.6 lock screen indicators (4 dots) invisible with solid black background

Additional testing results:

* Strangely, after posting this and using the phone for about 10 minutes, the four circles on the lock screen were visible again when using a solid black background.

* When I first noticed this issue yesterday, I noticed the four circles were visible at least once, then they were not visible on subsequent lock screens. During this time, I had a solid black background for the lock and home screens and did not make any changes.

* Now I tried setting different lock screen and different home screen combinations, and I tried leaving apps open and closing all apps before locking the phone to recreate the problem, but the circles are visible now.

* I am monitoring to see if the problem returns.

Additional testing results:

* Other solid VGA color backgrounds, not black or gray, the four circles are visible.

* Solid gray with RGB value <1,1,1>, four circles not visible.

* Solid gray with RGB value <20, 20, 20>, four circles slightly visible.

* Solid gray with RGB value <26, 26, 26>, four circles visible.

Motivation for solid black background:

This phone is for business use, and I designed a custom background with a solid black background and a solid white company logo in the middle. The black background blends with the face of the iPhone and the white logo provides strong contrast that catches attention. The obvious work-around of adjusting the black background to be a little lighter works but the contrast is reduced. Sure, this isn't a critical issue, but if you are a graphic designer or Apple, then these details might be important.

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