Ca I use acrylic inks?

You can, they are usually used for airbrushing but I use them for fine detailing like eyebrows or eyeliner.
They dry super fast though and removing them is hard, therefore I would only recommend them if you have a lot of practise or don't mind wiping the complete head over and over again.

 

I also use acrylic inks and love them for faceups. I've used them straight, but find they work best when blended with a little bit of matte medium and slow dri. This also makes them a bit more forgiving if you make a mistake. Just immediately dab water on and dry with paper towel. Slow dri gives you more work time and the matte medium keeps it from beading up. Add a little water to thin or make a bit more fluid.

The benefit for acrylic inks is pigmentation. They are rich in color, so even with a teeny bit of additives and water, they retain their darker colors.

 

I didn't like flow aid either, or slow dri or matte medium or any Liquitex or Golden mediums I tried. If you're in the US, I recommend Volks' acrylic color thinner! I really like the consistency and the paint stays wet enough that I can wipe up any mistakes. The paint will still dry on the brush after a short while, but not so fast that it's annoying. If I'm doing a lot of really long lashes on a head with big eyes, I can do about half the lashes on one eye before I need to rewet/reload the brush. Or sometimes I'll add more thinner and it stays wet longer so I can do a whole eye, but the paint is more translucent so I'll go over the lines a second time for richer color. (I tend to do that a lot anyway to get some nice color gradation on the eyelashes.)

Oh, and I've used this thinner with both acrylic paint and acryla gouache, so I'm sure you can use it with acrylic inks as well!

 

@masamune95 I'm not familiar with Tamiya stuff but if they have something that specifically says it's for acrylics, give it a try! I know Tamiya makes model paints, which are way more intense than acrylics, so any thinners designed for model paints will probably not be safe for resin.

 

I also don't like a lot of regular acrylic consistency for fine lines even with slow dri and matte medium (it's often too diluted in color, or too thick), but found adding just a hit of these two + water to acrylic inks is phenomenal. I will occasionally use watercolor inks (highly pigmented liquid watercolors) as well, but often to map out placements if I'm unsure before committing.

For most applications, though, I've resorted to almost entirely using Liquitex Acrylic inks. My fave colors for lashes and brows are Sepia, Burnt/Raw Umber, and Black~ I've also invested in a White, and Gold is an absolute favorite of mine!

Also, just the teeeeeniest bit of these goes a long way! I don't even usually use the dropper, just dab it onto my pallette and go with it~

I have not tried Volks Acrylic Thinner before, but I love trying new things out, so I may at some point!

 

I do now have some P.H. Martin's, but I've been using Marabu Graphix Aqua Inks with no problem. Heck, I've used them straight outta the container with no problems. Just use the very tip of your brush if you go this concentrated. Often, I've done this over top faint lines I've already added. Both straight and watered down can still bead up on the sealant, though. One of the reasons I still default to acrylic inks, especially for lashes.

I've not found Marabu to be terribly expensive, cheaper than my acrylic inks, though not sure of prices outside the USA. For both, though, one container can last forevverrrrr~

Also, not sure if this will help, but I made a video about a year ago showing off supplies I use, prepping acrylic inks, and showing how they apply for lashes. I don't use the watercolor inks in it, but I do show them and talk about them. I'll link it here in case you find something helpful in it:

 

I'm so glad things worked out for you!! ❤️