Sailor x BlueBlack Drink Series Double Choco Smoothie — 4ml Fountain Pen Ink Sample

Hue: A very dark, warm brown that reads close to black at writing size. The bottle label art shows a light milk-chocolate frappe, but the ink itself is considerably deeper than the packaging suggests — my swatches only reach that warm cocoa tone in the thinnest, most diluted areas. In heavy pooling it drops to a near-black brown with a distinct olive-khaki cast; the small splatter dots dry to a rusty red-brown.

Shading: Moderate in swabs and broad strokes, where it moves from light chestnut through to near-black. Much subtler in normal writing, where it largely settles as a dark brown.

Sheen: No metallic sheen visible in my swatches. The olive-green tone in the heaviest pools appears to be an undertone of the ink rather than a reflective sheen, though I can't rule out a faint one in wetter nibs on coated paper.

Shimmer: None. 

Flow: Wet.

The interesting bit: BlueBlack is a pen and ink shop in Jongno-gu, Seoul, which commissions its own shop-exclusive inks. Their Sailor collaboration is a series themed around drinks — the shop's line-up currently runs to sixteen, alongside the likes of Cherry Coke, Melon Soda, Highball, Pistachio Shake and Misutgaru. Double Choco Smoothie takes its name from the Korean café staple, the double chocolate frappe, and the label carries the Korean 더블초코 스무디 alongside the English. It comes in Sailor's faceted square 50ml bottle with the cap engraved "[BlueBlack] Limited". Worth knowing that the ink is a good deal darker and more sombre than the cheerful packaging implies.

This is a hand-decanted 4ml sample vial from my own bottle.
Photos are my own swatches on Tomoe River Paper.
I'm a collector and I'm always happy to talk ink, so please message me if you have any questions.