I'm curious about why you're inspired to try/use new colors.
Right now, as the leaves start to change (a bit prematurely) to their autumn colors, I'm looking for inks that match the colors around me in nature.
I'm currently craving a particular shade of blue that would match a sweater I'm making. It is somewhere between Diamine Cornflower, Lapis, Tudor, or J. Herbin Blue Ocean (if I feel like going shimmery). I want to track down samples of each of those. It isn't necessary, as I have plenty of blues and plenty of inks in general. I don't always go for matchy matchy. There's no need to match a sweater and my pen's ink, but I'm inspired by the color of this beautiful yarn.
Other times, I crave a contrasting, but complementary, color. A deep burgundy ink to go with some deep teal items a close friend gave me, for example.
I've used a particular shade of pink (Diamine Carnation) because it reminded me of my grandmother. A particular red (Diamine Monaco Red) because my mom would like it in the pen of hers that I have. Quick Blue-Black reminds me of my dad and of my intro to fountain pens. I rotate varying purples in a pen that was a gift from someone who loves purple (though in general I'm neither someone who must match inks to barrel color nor someone who avoids it entirely).
From other posts, matching seasonal colors is something that many people here seem to do. Others look for colors that match logos or team colors. I always enjoy reading these threads, but I haven't found a broader discussion of this topic.
Why are you motivated to look for a particular shade of ink?
If you're looking to match something else, what is that item?
If you have a signature color or usually use only a particular color family, when/why do you branch out?
Thanks for sharing your thoughts.