Ukrainian folk festival, that comes when the harvesting is finished.
Ukrposhta notes 2 variants: one of light tones, another of dark tones. It is possible that this note describes variant luminescent features, one brilliant, the other dull (this variant). Luminescent features: Text "УКРАЇНА - UKRAINA", towel, shirt on a girl glow yellow under UV.
Microtext "М. Кочубей".