1. A method for color visualization of 3D image data of an object using a rendering technique, the method comprising: calculating pixels of the object from the 3D image data by applying a transfer function, which assigns color values of red, green and blue to the 3D image data, and providing said pixels as an image with a bright background; inverting the image with the bright background to visualize the image on a dark background, wherein the color values assigned to the 3D image data of the object in the transfer function are modified when calculating the pixels by modifying the color values in accordance with the following rule: R′=max(max(G-R, B-R),0) G′=max(max(R-G, B-G),0) B′=max(max(R-B, G-B),0), wherein (R,G,B) corresponds to original color values of red, green and blue, respectively, in the transfer function and (R′,G′,B′) corresponds to the modified color values of red, green and blue, respectively, and displaying the image obtained by the inverting in a display area.