Colour Challenge: Indigo Violet

This is the only remotely indigo thing I have seen this week in nature: a violet. This one is probably one of the subspecies of Viola tricolor:

^{Olympus Stylus 1s, 42mm, ISO200, f5.6, 1/125s}

I have also found its very rare cousin, the marsh violet (Viola palustris), moerasviooltje in Dutch, in the local peat bog here, but that one isn't indigo:

^{Olympus XZ-1, 28mm, ISO100, f8, 1/100s}

Thanks for watching!