Lets not forget because the digitally enhancement, air brushing and photo shopping are the on-set lighting, hair fans and computers.
I had the good fortune to attend a photo shoot for HairUWear some years ago when a major blonde celebrity was the cover model for all of the catalogs.
Not only was there a hair and make-up person by the celebrities side every second, there was a fashion stylist, a manicurist and a massage therapist. The set was full of big hair fans and special layered lighting. The photographer had a sophisticated computer and every shot was instantly uploaded to his computer where he was able to figure out how to adjust the set's lighting to capture the best angles, the best shine on the hair and etc.,
The way the celebrity looked in the dressing room and how she looked in the finished photos was like night and day. Also, she was wearing layered hair extensions.
Even if we could see Doutzen-Kroes in person right after this photo was taken she would not look like this.
I am SO glad you are all talking about this. It's so important that "real" women understand what goes into a supermodel or celebrity's hair styling on set.