This is my second review in the new line of Blackstone CMYK Fountain Pen line of inks, that are designed for mixing - and to date it's probably my favourite (unmixed, i.e. base) ink in the range. Magenta is a strong, reddish-pink colour that's clearly visible on the page. It's a smooth, lubricated ink that's very well behaved in the pen and on the page.
For more information on the ink range, and full disclaimers (I bought these inks with my own money!), see my earlier review of the Cyan ink at http://www.fountainp...cmyk-inks-cyan/ - or you can check out the product range at the Blackstone Inks website (http://www.blackstone.ink/index.php/blackstone-cmyk-ink-mixing-set).
Here's a scan and a photo of my written review - I think the scan is a little more accurate for colours.