Seeing as I seem to be more obsessed with fading and the question how inks hold up over time than most other members here, I carried out my own test and put several of my inks in a sunny window for two months (in winter & early spring, so there hasn't exactely been an extreme amount of sun). Here's the result.
First the 'before', then the 'after' scan:
Click to view attachment
As you can see, Noodler's blue has held up very well, although it did lose some of its vibrancy and green tones so that it looks a bit more like a regular blue now. This blue actually became darker rather than lighter (as you would expect).
P.R.'s Lake Placid has lost all of its blue elements so that it looks purple now (it is still perfectly legible, though), and
the one third of Pelikan red has completely disappeared from my mix, so that only Noodler's Cayenne remains. The latter also seems to have lost some of its red dyes.
My two blue & blue-black mixes have held up quite okay and are still absolutely legible, which is interesting because both Quink 'permanent' blue and Sheaffer Scrip blue-black fade fairly quickly on their own. I should mention that the blue-black mix looks much more like a real blue-black with black and greenish tones than what is shown in the scans (both the 'before' and the 'after' scan do not adequately show the colour I saw/see on paper).
Noodler's Hunter Green ('Eternal'/'bulletproof'), Gruene Cactus (regular) and Fox Red ('Eternal'/'bulletproof') have also held up very well. The bulletproof colours look a bit duller and less vibrant now and both greens have lost some of their yellow hues. Nonetheless all three inks remain perfectly readable.
[Apart from Pelikan red, which didn't leave a trace behind (s.a.)] Diamine Maroon and J. Herbin's Poussière de Lune are the only 'losers' in this test: they have faded almost completely. I can still make out what I wrote in the original note, though, if I make an effort. I find this surprising as on their website J. Herbin claim that their inks are very lightfast.
I added Schneider turquoise, the Pilot Cherry Pink that comes with the Petit pen and the Platinum green that comes with the Preppy pen to the inks in the window some days later. As you can see, they have all faded considerably, so that you can hardly see them at all in the scan. While what I wrote in Platinum green and Schneider turquoise is still legible with some effort, the Cherry Red is not readable in the original note anymore, either.

I posted this in the reviews section, because lightfastness is a factor which is often left out in ink reviews (understandably enough, as you can only tell with time) and I hope that others will add their own tests of different inks to this thread and that it will be helpful to members who decide which inks to buy. Maybe the thread could even be pinned once it has more tests of a variety of brands?

Thanks for this. I've moved it to the "Tests" sub-forum, which is a more appropriate place for it.

Thanks again,

Chris

I have now done a more extensive test of all of my inks. This time the inks have been exposed to more UV-light as they've been in the window for two summer months. However, my comments from the first post still apply to the new test, too. The only thing that was a surprise to me is how well Lamy Black and Herbin's Rouge Opera held up.
Here are the scans:
Click to view attachment

Btw., has anyone done a fade test of Visconti Blue and Diamine Kelly Green by now? They're two inks I'm really interested in.

interesting.. you have no purples, no oranges, no browns!

i've been slowly assembling a list to try this with, but i don't have the time to dip everything, and i want the samples to be pure for each color, which is a rarity in my pens!!!

I like how Spearmint looks afterwards!

Thanks! A great test!

This is a fantastic, truly useful test. The rest of us should be very thankful you take the time, effort -and money- to upload such great comparison job. Thank you.

Lamy Black just went up a few notches in my estimation!

You aren't the only one obsessed with fading. But you have more inks than me and much better handwriting.

My test ran 73 days, only because I forgot them. Results are in this thread where they have largely escaped notice.

http://www.fountainpennetwork.com/forum/in...st&p=637859

Wow, that's interesting, John. I didn't know that PR Supershow also faded to a purplish colour. And Midnight Blues - originally it's such a dark colour and it just left a faint trace after your test.
Maybe you could put the picture in this thread, too?
Thanks, everyone, for your kind words!! Actually fading tests aren't a lot of work, so I don't mind doing them at all .

Here's another 2-months-in-my-window fade test, this time of my new acquisition Caran d'Ache Sunset. I've included Diaine Maroon for comparison, and you can also see black ink from one of the cartridges Tryphon sell (VERY lightfast & highly recommended).
Click to view attachment