I like Pelikan Royal blue. I started writing with this ink and have used it for many years without ever using any other, in the era of one pen / one ink.
I still like how it behaves and looks. It's just a pity it tends to fade and on some papers more than others tends to look somewhat washed out.
I like the colour shade, I know it tends slightly towards purple, but then again it would not be Royal otherwise.
I also like how it flows, the fact that it's quite dry on absorbent paper, and can shade nicely especially on coated paper.
Since I also like Pelikan pens, with time I have built up quite a reservoir of Royal blue, not by choice but by chance, since many Pelikan pens, especially special/limited editions, come with a complementary bottle of Royal blue.
Nowadays that I've moved also to other inks, although with a great prevalence of blues, I'm often using my reservoir of this ink for experiments.
Typical tentative mixes are blue + black, blue + purple. I'm not so fond of blue + green, although I have used this ink in view of its purplish tinge to make some blue-green inks look more neutral.
This mix I'm showing here is a not so obvious: blue + blue.
I happened to think, as this experience is already confirmed by adding either black or purple to this ink, that adding some darker, more saturated ink to Royal blue may affect it positively, and that should work also by adding another blue.
I did not have to think a lot about it, I have a sample bottle of Sargasso sea, and since I like this Diamine ink, I also have a full bottle.
The sample bottle is half full and the perfect available darker shade to add some character to Royal blue.
I had planned to try different ratios but it also happens that I like the first tested ratio, and did not go ahead to try others.
Pelikan Royal blue 4 parts to Diamine Sargasso Sea blue 1 part.
I'm using a vintage bottle of Royal blue, which was unopened when I got it a few years ago, but is now in use since a while (more than 1 year surely).
I do not notice much difference vs current royal blue, perhaps just a tad more greyish.
I used two separate ordinary metered syringes, to avoid contaminating inks, and put 4 ml of Royal blue + 1 ml of Sargasso sea in a sample vial.
I then just closed and stirred the vial.
This is what it looks like, you can already see the mix is less purple than Royal blue.
I then tested the resulting mix vs the two starting inks. A very quick comparison.
Some brief impressions
The mix is darker than Royal blue and lighter than Sargasso
The mix is less purplish and more blue than Royal blue
The mix has a faint turquoise hue
The mix has some shading although more evident on glossy paper
The mix is dry on copy paper and more wet on glossy paper, much like Royal blue
The mix has no sheen compared to Sargasso
The mix looks more contrasted and less faded vs Royal blue
dry time is about 10 seconds on copy paper and about 25 seconds on glossy paper, when dry it does not smudge further
a closer look vs Sargasso, it's still quite saturated despite being less concentrated
The pen used was a Wing Sung 3008 with a Lamy B nib
(don't judge the sloppy writing...)
I have not tested compatibility, but I am not expecting problems with these two inks. The vial will sit there on my desk for a while in any case.
Then I'll probably fill a nicer pen and take it to work.