I've worked with a few fountain pen inks. I've used Sheaffer's (cartridges), Parker's (cartridges and bottled), Waterman (bottled, since I don't have one of their pens), and Noodler's (bottled only--I don't think they do cartridges).
Sheaffer's cartridges are simple cylinders with a circle etched at one end that you have to punch the fang of the feed through. The ink is...not bad. You can get several different colors, since most hobby shops carry the Sheaffer calligraphy pens, and calligraphers tend to like different colors of ink to play with. My Sheaffer calligraphy pen is one of their older, semi-transparent plastic No Nonsense pens, with a fine calligraphy nib. I've currently got it loaded with the red cartridge because I was working on a calligraphy project, and thought the red against the sort of cream-yellow parchment worked best for it: Roy Batty's death monologue.
The Sheaffer Scrip ink is...satisfactory. The color is rich, and the flow is smooth and instant, even though I haven't picked up that particular pen for about three months. Even though the pen is using a calligraphy nib (comparable to a broad fountain pen nib in how much ink is laid down), there's no show through, much less bleed through.
If you want to use Sheaffer ink, it does come bottled. Prices range from about $9.27/50 mL (about 1.5 fl. oz) bottle (in the three packs) to about $14.50 or a bit more. Yes, it comes in several different colors. Skimming over Amazon, I saw most of my favorite ink colors: purple, blue, turquoise, green...only burgundy was missing.
Next up: Parker Quink. I've used their cartridges (my first fountain pen was a red Parker Vector with a fine nib in red, which I'd still be using if it wasn't so skinny) for years, usually in their washable blue Quink. That never shows through, which permitted me to take copious notes on both sides of any notebook paper I used. I still have about five or six cartridges (which are HUGE by cartridge standards--I could use the same one for a week of grad school note taking and fiction writing). They are proprietary--they will only work in Parker pens. However, Parker does make bottled Quink. I have one in black "permanent" (which only means it takes a bit more than just water to get off).
The bottled ink is also quite well behaved. I've used it in several different pens, with no show-through or bleed through, no matter what nib size, or how generous the pen is with the ink. The main downside of Parker Quink is that it only comes in four colors: black, blue-black, blue, and red. That's it. No fun colors. Just sensible business/grading colors. If that's all you need, their bottled ink comes in 2 oz bottles, and ranges from $8-$12 on Amazon, depending on from whom you order it, and what color you order.
Waterman bottled ink also behaves fairly well. I've used their turquoise (Serenity Blue), their blue, their red, and their green. I really like their green, and currently have it loaded in one of my Jinhao 250s. It has never bled or showed through, and neither has their other colors I've used. Their blue, though, is a little blah. They also make their ink in brown, purple, blue-black, and black. When I first ordered ink, though, Amazon didn't have a line on their purple, and I really wanted purple. So...
Noodler's ink. These inks are beautiful, and come in all colors. I have their purple, burgundy, Bernanke Blue (very fast drying blue), Ottoman Azure (shades from deep blue up through turquoise, depending on line thickness and amount of ink laid down), Bulletproof Black, and Bad Belted Kingfisher (a navy blue, or blue-black, if you prefer). Their colors are true, rich, deep colors...that tend to feather and show through on cheap paper like mad, when they're not bleeding through and spotting the page beneath. I do love this ink. I love it enough that I've gone looking for paper I can use it with--successfully. Decent journal paper (which I use for fiction writing) works, as do the Sam's Club brand legal pads. There are a few notebook brands that have good enough paper, but not very many. And no, the specific nibs on the pens don't save your paper: I've got several different Noodler's inks in everything from a medium to a fine to an extra fine nib, and there's at least a little show through with all of those nibs. It's normal with super-saturated inks.
Noodler's has more ink colors than any other manufacturer I've run across--I've seen ink in every color and hue of the rainbow. Gorgeous stuff.
Another thing about Noodler's inks that is pretty special: they have several colors of ink they term "bulletproof": the inks are resistant to most forger's techniques, and are, therefore, safe to use on contracts and checks. The inks themselves bond with the cellulose in the paper, and are mostly to fully waterproof, won't come off with acetone, acid, UV light, or any of the other commonly used tools. I've got their Bulletproof Black--which is fully waterproof, once it's dry--and Bad Belted Kingfisher, which runs, but is still legible. Both take for-bloody-ever to dry, especially on smooth checkbook paper, so you'll need a non-lotioned tissue paper to use to blot. I have one pen loaded with the Bulletproof Black (which is a softer shade of black, not hard and sharp like some), and one loaded with Bad Belted Kingfisher. Yes, I use them both for legal purposes, and honestly, I prefer using the blue on contracts over the black to make clear the difference between an original and a copy.
There you have it: my non-professional walk through of all four ink brands I've used. I can't recommend any over any of the others--they all have their pros and cons. I suppose it depends on what you want: standard colors that won't bleed through? Gorgeous colors that will? Washable or permanent? The ink I would recommend depends on what you want to use it for, whether you want to use cartridges (in which case, if you've got a pen that takes proprietary cartridges, like Parker, Pilot, Lamy, or Waterman, you've got little choice), or whether you want to use a converter, or use a syringe to refill old cartridges with bottled ink, or whether you are using an antique pen (or replica) with a dedicated filling system and have no choice but to use bottled ink.
I only wish I could afford to try some of the different inks I haven't tried yet. ;)
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