RESULTS

After analyzing the data, the results were better than anticipated. The overall ∆E average of all the devices was 15.15, which is not good, considering 4 Δ units is where the bar was set. The top two ∆E devices were the Nokia Lumia 920 (7.93) and the HTC Windows Phone 8X (9.07). 

Sample Ranked by Delta E (ΔE)
1	Nokia Lumia 920	7.93
2	HTC Windows Phone 8X	9.07
3	Apple iPhone 4	12.34
4	Apple iPhone 5	14.01
5	Apple iPad Mini	15.01
6	Microsoft Surface Pro	15.84
7	Microsoft Surface RT	15.86
8	Apple iPad Mini	15.98
9	Samsung Galaxy 3S	19.41
10	Apple iPhone 3GS	20.30
11	Apple iPhone 3GS	20.93

The rest of the device display ∆E’s were greater than 12. But if the differences between the ∆L*, ∆a*, and ∆b* are assessed separately, the differences are improved.  Nine devices resulted in a ∆L less than four with an average of 1.78. Five devices had a ∆a less than four with an average of −2.58. Eight produced a ∆b less than four and an average of 1.35.

Individual Coordinate Differences
		Δ L	Δ a	Δ b
1	Nokia Lumia 920	2.24	-0.78	4.48
2	HTC Windows Phone 8X	2.63	-1.37	1.6
4	Apple iPhone 4	3.01	-5.43	1.14
3	Apple iPhone 5	-6.53	1.77	1.54
7	Apple iPad Mini	2.07	-6.3	1.9
5	Microsoft Surface Pro	0.29	-5.17	2.47
6	Microsoft Surface RT	2.89	6.12	3.42
8	Apple iPad Mini	1.19	-7.03	2.85
9	Samsung Galaxy 3S	2	-2.13	8.96
10	Apple iPhone 3GS	8.73	-3.87	-12.34
11	Apple iPhone 3GS	1.02	-4.15	-1.12
	Average	1.78	-2.58	1.35

An assessment of the ∆a values shows that all but one mobile device display tended to be more green than red; nine devices were more yellow than blue for the ∆b value. Only the iPhone 5 had a negative ∆L. The colors best rendered were black and gray.

SECONDARY HYPOTHESES

The secondary focus was to determine if two devices of the same model would have a large color difference. I measured two iPhone 3GS and two iPad mini’s. The iPhone 3GS had been in use the longest and it showed in the numbers. The average ∆L was 4.14, ∆a resulted in −2.03, ∆b averaged to −6.83 and the ∆E distance was 20.85. Green, blue and magenta had the biggest differences. One device had better lightness and had better consistency with color.

The iPad mini’s were purchased at the same time and had about the same amount of use. These two devices were more consistent than the 3GS. The magenta and blue had bigger ∆Es. The average ∆L was 1.63, ∆a resulted in −6.67, ∆b averaged to 2.37 and the ∆E distance was 5.49.

Data