I have told about it in the topic
Green wood. Vacuum impregnation instead of drying http://www.penturners.org/forum/showthread.php?t=82460
It was just a malus, that 3 years was under snow and rain.
After vacuum impregnation wood got so beautyful texture.
Cmall light pieces on the left - wood before impregnation.
By the way, there is vacuum impregnation (with same BLO) on other wood:
Platanus. It becomes worse (less contrast).
Middle piece on this pen and thumbdrive - platanus without impregnation:
Karelian/Masur birch. It becomes worse too - wood lost curly shine.