Adding a middle mark to a dark rope

So I have been climbing with a black 9.2mm Petzl Volta (see below) for about 3-4 months now, and while I love the rope itself, one thing I cant stand is the middle mark. Now I'm not exactly sure who thought of the brilliant idea to put a black middle mark over a black rope, but it has recently led to a couple less-than-ideal rappels for me. In the daytime you can sometimes find the middle mark if you spend a couple minutes looking for it, at dusk/nighttime rappels, your best bet is to hold a coil in each hand until they feel about the same weight. I want to add a better middle mark to the rope, but I am stuck on what to do. The two options I can think of are either a.) taking a metallic silver sharpie and trying to create a silver middle mark. or b.) take a piece of orange thread and sew a couple loops through the sheath for a middle mark. Opinions?

And yes I know the sharpie will melt away the core fibers and the needle will cut them and pretty much all in all I'm gonna die, but what experience or recommendations do people have for marking dark colored ropes?

The thread is the way to go

They also make reflective and/or glow in the dark threads

I used a 1/2" piece or white athletic tape for years.  It comes off after a while but just replace it, and many climbers have this in their kit anyways.

I am addicted to bi-color ropes now and pay the premium added to the price.

I used dental floss. Just don’t sew beyond the sheath 

Food coloring or fabric dye

just cut a thin strip of first aid tape. used one on one of my ropes for years. when it starts to get a little worn, just replace it. it dosent move much even going through a belay device, and it dosent leave much of anything on the rope sheath after a long period of time. its also very easy to spot the center of the rope with it..

This might not be the answer you are looking for, but is a better solution than searching for a middle-mark on a black rope:

When ropes get dirty I will flake the rope from the ends at the same time to find the center after I have threaded through whatever I am rappelling from.

see this thread for some ideas, including reflective tape and strike indicators sewn i to the middle.

https://www.mountainproject.com/forum/topic/116554631/middle-rope-mark

I vote for weaving some thread into the sheath of the rope.  Embroidery floss seems to work well.

Another for weaving thread in the sheath.  It is the middle after all.

Not a fan of searching for it from the ends. Takes too much time sometimes. Does not allow easy reverification.