According to Microsoft Paint, the luminescence values of the two pixels diagonal to the baseline pixel are 68 and 75. Interpolation of these values gives (68 + 75) / 2 = 71.5. The luminescence value of the baseline pixel is 120, and the maximum potential value is 240. ((120 - 71.5) / 240) * 100 = 20. The pixel from the middle stroke of the "E" has a luminescence value of 105, with a value of 68 for the pixel diagonal to it. ((105 - 68) / 240) * 100 = 15. As 20 - 15 = 5, it is to be concluded there is only approximately a 5% difference in luminescence, relative to the diagonal background patterns, between the baseline pixel and the pixel from the middle stroke.

Visual depiction, represented by the red lines.