1. A method for processing high dynamic range image data which includes pixels whose values have a high dynamic range, so as to obtain counterpart image data which is renderable, the method comprising: using computer to perform the following steps: classifying each pixel of the high dynamic range image data into one of at least two different portions which include a relatively lighter portion and a relatively darker portion; identifying an image adaptation point for each of said different portions, said identifying step including the steps of identifying a first image adaptation point for the lighter portion and identifying a second image adaptation point for the darker portion; and performing white point adjustment for the value of each pixel in each of said different portions by using the corresponding image adaptation point for each said portion, said step of performing white point adjustment including the steps of performing a first white point adjustment for the values of pixels of the lighter portion using the first image adaptation point and performing a second white point adjustment for the values of the pixels of the darker portion using the second image adaptation point.