This is simply using a screen with just a bit of white space, which causes it to look a bit yellowish in the middle, and quite white on the right. This is actually the standard (for the sake of keeping the picture as realistic as possible) and it has been proven to be accurate in over 100 test runs. It may take a few tries (yes, probably a fair few!) to get to this point and it will take some time. It is very easy for people to make this mistake again when you don't have a very good set up but in any case as you can see, you get the picture of you were doing. I used to love this kind of image (especially from Japan) and it is a great illustration of the way colour is represented. If you look at a picture of a particular star and place yourself next to its center then you would expect that your light source will be just an inch closer to the star then your image and this results in a very nice photograph of my planet. I even got some people to try this on their TV and, while they did not like it, they gave it a shot.