Originally Posted by
Microbial:
“I've looked into this a bit more and it seems that purple doesn't exist as a colour, it's just a human interpretation of the mixture of red and blue (http://www.davidberryart.com/articles/purple.html is interesting). Digital (and film) cameras are recording a different reality.
This makes me feel better about the camera and I'll look at pre- or post-production corrections.
The question, then, should have been "Why does an iPad's camera record purple?".”
All digital cameras only record Red Green And Blue. LCD/ plasma displays are the same the screen is composed of pixels with 3 sub pixels again Red Green and Blue.
You can create any colour by mixing Red Green and Blue. Normally a digital camera will use 24 bit colour. This gives 256 variations for Red Green and Blue which equates to over 64 million colours. The colour of the light illuminating the scene affects how the 3 colour pixels react. Outdoor daylight is biased towards the Blue and Incandescent lighting is very Red, without compensation photos taken under fluorescent lighting look very green.
A camera has to compensate for this normally using an automatic setting. Some will let you set colour balance manually by focussing on a sheet of paper/card which is neutral grey. This should give the most natural colour rendition.
My grandsons school uniform was purple, it's quite hard to get it to look right on a photograph even when taken with a high end DSLR. Photoshop is able to colour correct automatically by you locating a neutral grey point in the picture.
The consumer end version of Photoshop (Elements) is available for about £50.00. Recommended if you are serious about digital photography.