Here is a pic of the whole plant. All of these seedlings have identical form and are easy to identify amongst other crosses. They all have slender grey stems that have little variation in thickness along their length and very little in the way of caudex at this time.
Brian UK.

Brian,

It looks yellow on my calibrated monitor. Yay for Mr. Ko's pollinating skills and for your nurturing as well!

If you have a piece of Lego lying around, you can use that to kind of benchmark the colors on your photos. I am assuming, of course, that most of us know what Lego blue looks like, for example.

Pagan

Brian, possibly the color will deepen with age or in a humid environment may be darker? Although your greenhouse is probably humid.
I think for what they call 'yellow', it is a yellow. So many Yellows that I have thought about getting, but they are seldom what the advertised photo's show.
Seems that holding the yellow color for any length of time is the toughest for them.
Beautiful bloom.
Rick

Looks like a yellow to me ...I've always had this trouble on distinguishing light yellows to dark yellows.

The picture that I will post is the yellowest that I've ever had.
*please excuse the picture ...it was taken at night. I will bring in tonight and put it close to something yellow I have and repost the pic.