Thank you Olivier!
I tried different backgrounds, but I still have issues with olive drab or similar colors (on black backgrounds the dark planes planes are always overexposed). I have an older DSLR, and it's dynamic range is not the best. I really struggle to find the proper lighting and camera settings for those dark colored models.
I will continue experimenting, but I will not have time in the near future.
17. February, 16:12