Diamine Dark Olive is exclusively made for the Philippines and is an attractive yellow-green ink.
It’s an unsaturated ink that exhibits some nice shading ranging from yellow-green to dark green almost black.
I found it flowed well with all of the pens I tried it in, and lubrication was smooth enough across the page, although it could have been a bit smoother. Dark Olive felt drier than Lapis Blue (the other Philippine exclusive) and drier than Classic Green (Diamine UK standard range.)
My review was written on HP Premium Choice ColorLok 100gsm smooth coated paper from Staples. It’s not very absorbent, and I saw no spread, feathering, show-through or bleed-through.
Dry time was quick, within 12-14 seconds on my test.
Dark Olive is not sold as a waterproof ink but showed a little water resistance.
For those who may find Dark Olive hard or expensive to obtain, I would suggest Diamine Safari or Classic Green are good alternatives.
Nib Dry-out: Not noticed.
Nib Creep / “Crud”: Not seen, even after several days in the pen.
Clean-up: Easy from hands and pens.
Clogging: Not seen.
Not available from Diamine Inks UK. Available in 80ml glass and 30ml plastic bottles within the Philippines.