The colours in the photograph are the result of coloured dyes reacting with the incoming light. These dyes never react at the same speed as each other so the colour balance is always slightly out.
Flowers which are a violet colour have very high infra-red reflectance. We can't see it because our eyes don't detect these wavelengths. But the red-sensitive dye in some photographic film does detect it to some extent. So when the film is developed there can be a red or pinkish tinge to the flowers.