What lighting was used?
We tested under the subdued natural daylight found in houses, under warm tungsten lighting (a lamp), and bright fluorescent lighting in an office.
Under fluorescent lights, all testers named image #3, above, the worst. Under tungsten lights, some people chose #5.
What papers and finishes?
All prints were luster. Kodak Endura Professional for WHCC, Bay Photo, Miller's and Mpix; Fuji Professional for McKenna and ProDPI.
A mounted canvas from Mpix (not part of the test) came back as blue as print #3, above (see it).
What were the testers asked?
"Pick your favorite print from each set, and tell us why you like it best. Pick your least favorite. What don't you like about it?"
Least favorite was often easy, as in the print above. They usually debated their favorite.
How did you pick these shots?
We tested the most common complaints: prints too dark, skins too red, yellow or cyan—or landscapes lacking vibrant colors.
We should have added a bride and groom to test white dresses alongside black tuxes.
Who were the testers?
Most were North American Caucasians whose bias seemed to be toward looking tanned.
However, two fair-skinned Caucasians (one a strawberry blonde) and one Asian-American passionately disliked a yellow bias and preferred ProDPI, above.
What about EZ Prints?
They're a prosumer lab in Georgia with consistent, great results. They're the default lab for SmugMug and print for many other high-end outlets.
We didn't include them in this test because we send millions of prints through them a year and measure customer feedback daily. However, they don't offer the high-end color correction, packaging, and papers that Bay Photo does.