Cornflowers are a very unique blue, looking them up I discovered why!
"The ions that bind in cornflower blue
 
Roses are red and cornflowers are blue, but both flowers are 
coloured by the same red pigment. This conundrum has puzzled people for 
90 years, but finally scientists have worked out what makes cornflowers 
blue, publishing their findings in Nature. Kosaku Takeda of Tokyo 
Gakugei University in Japan, and colleagues, used x-ray diffraction to 
investigate the structure of the cornflower pigment. They discovered 
that the bright blue colour comes from the arrangement of four metal 
ions, which bind to a complex of six different molecules, made up from 
two pigments. This pigment structure is completely different to the 
pigment found in other blue flowers. A strategically placed iron ion and
 magnesium ion give the blue colour, while two calcium ions give the 
structure stability. "This tetrametal complex may represent a previously
 undiscovered type of supermolecular pigment," says Takeda".
from The Guardian Thursday 11th August 2005.
They remind me of Van Gogh paintings - perfect with Poppies! Difficult to match such incredible Iron and Magnesium ions against printed CMYK colours(!) but here's my very best attempt...  
 
 
Happy 4th July! and very Happy Birthday to my son Josse! xx. This is a detail from his Graphic Design degree show at  Central Saint Martins a few weeks ago. He's designed a Font which can't swear - brilliant!! See more of his work at.. 
http://cargocollective.com/Jossepickard
...from my seasonal colour sample notebook.