Bottle and pricingQuick note here. To my dismay, when I was putting this review together, I noticed that Diamine has increased their ink prices across the board, by roughly $2 per bottle. While still relatively inexpensive, I'm a bit saddened that this happened. Here are the new prices then. Notice the price per milliliter jumped by $0.02.
Bottle capacity: 80 ml / 2.7 oz
Price / ml: $0.19
Color and saturationDiamine China Blue is a medium saturated blue, quite similar to denim. It looks darker when freshly written and still wet, but it resembles a faded pair of blue jeans when it dries.
In the comparison below, Diamine China Blue is set against Private Reserve Invincible Aqua Blue, and Waterman Florida Blue. These are the closest colors to China Blue that I could find among my previously reviewed inks, especially PR Aqua Blue (which is discontinued). Notice how China Blue is just a little less vibrant than Waterman Blue and perhaps a fraction warmer in tone.
ShadingDiamine China Blue shows a fair amount of shading, even though it might not be apparent at first. Your results may vary, of course, but a thicker nib will bring our the color variance nicely.
FeatheringI'm a little on the fence here. Diamine China Blue seems to be causing a tiny bit of feathering on cheap paper with the broad nib but I'd wager that doesn't happen with a medium or thinner nib on the same paper. That's definitely not the case on Clairefontaine.
BleedthroughWhile it doesn't outright show through on cheap paper, China Blue exhibits enough ghosting to be iffy on this type of paper, provided you want to use both sides. I still do though, but it's mostly for jotting down random notes, so it doesn't matter to me.
Flow, lubrication, and smoothnessDiamine China Blue is very smooth in the Kaweco Sport. It is also rather wet, which probably contributes a little to the small amounts of feathering and ghosting. As mentioned before, it looks much darker when it is freshly laid on paper but lightens up as it dries. In general I like that in an ink, because it's almost like it has two personalities.
Drying timeOn cheap paper Diamine China Blue dries almost instantly, aided perhaps by the good absorption rate. On Clairefontaine it took close to 1 minute to dry completely, although in fairness that's what usually happens with a combination of broad nib and wet ink.
Smearing when dryNone.
Water resistanceThis isn't a water resistant ink and it shows. My standard test which exposes the ink to water for 1 minute didn't wipe it out completely, and there are still faint traces of it on paper, but I wouldn't expose it to moisture.
ConclusionDiamine China Blue is a fairly run-of-the-mill blue ink, well behaved overall, with no single feature standing out but that's just fine because it makes for a reliable ink. The blue color is pleasing, dependent on your tastes of course, and you can definitely use it in an official capacity. Just make sure to use it on higher quality paper because it doesn't play very nice with the cheap stuff. Personally I'm not big on blue inks, especially since I prefer even more personality (read deeper shading and unique tone) but I can still recommend China Blue without any reservations.
Below are the two samples on photocopy and Clairefontaine 90g paper, respectively.