In my case, the problem comes from the fact that I use a lightbulb for both lighting and heat, which means that the light is yellow, instead of natural white. The yellow is exaggerated in the photos, so I have to edit the images to make it look about the same as in real life. As a result, some of the colours get lost.

I used the flash in the first picture, but you can't really use it in close-ups.