Special? No. Just plenty of good light and maybe a magnifier so you dont go BLIND.
(I dont know how people work on 22 count... )
If by "needs to be done with 18" you meant "projects that should be stitched on 18", then I would say anything that you want to have a smoother finish, where you cannot see the x's... and even the squares are small enough such that the pattern doesnt have that "pixilated" look.
Some projects are just TOO BIG on 14, so I sometimes use 18 to make them smaller...
I don't use Aida very often any more, as I have become accustomed to lots of evenweaves and linens, 28 ct being may favorite (equivalent to 14 ct aida). But, for my SQ design, I am using 22ct, and so far, it's working great! If I could've found 20, I would've used it, but I couldn't come across any easily, and I was ready to start. Next time....
Finished size is my primary issue when choosing fabric count. If you've not worked on linen or evenweave, feel free to ignore this part. If it has blends, like SQ does, 14/28 is the largest I go, as it will be done 2 over 2. If it isn't blended at all, and has no backstitching, I very likely may do it 1 over 1, 28 being the starting point for that. I haven't done over-1 on 36 ct yet, but I have a few samplers in the stash that might get done that way.
As far as what needs to be done to the fabric before starting, just finish the edges like you would any other fabric, so it doesn't unravel as you work on it. I used to be bad and use masking tape, but over the years, have learned new tricks. When my sewing machine is in good working order (not often - it's older than I am ), I'll zig-zag the edges. Lately, I've been using Fray Check, and that seems to work just fine for me - quick, no bobbins to mess with. Stretch the same way, unless you are an in-hand stitcher. I use scroll frames, hoops, Q Snaps, depending on project size - I did crewel way back when in-hand. I think; I honestly don't remember. Sure don't remember having a hoop, so I must've done it in-hand, but that would drive me over the edge, now - must have good tension!
Hope this helps, and I didn't open a can of worms for you with the evenweave/linen part
Yes, I must say that I'm a bit of an evenweave devotee as well- so much softer on the hands and eye. I usually go for 28 for simple things or 32 for subtle blended masterpieces- any higher than that and my eyes give up. I have done the Aida thing in my day though and I'd have to say that my favourite is 16- not too big and blocky, not too little and squinty, just right.
The important thing is what you want it to look like. If you have any fabric showing, you should just kiss the idea of aida goodbye and go for linen (and then you can play with colours too!). If you have no fabric showing, then you want to focus on the stitching- how do you want it, bright and blocky or soft and blended? Blocky go lower count, blended go higher. It also depends whether you want something the size of an Egyptian rug on your wall or an itty bitty minature.
Ah, the choices the choices, isn't that what makes us all carry on!
2 over 2 and 1 over 1 are things that only apply to evenweave (linen or cotton or blends...) it refers to how many threads you are stitching with and how many strands of the fabric you make one cross over- if you are sewing with two threads you usually work a cross over two threads of the fabric, and if you want finer work you may choose to stitch with only one thread and in that case would work each cross over only one thread of the fabric.
I personally prefer evenweave because it's softer and more malleable, feels more like a piece of the family linen than a fabric which is designed to be covered up as much as possible! I also find that my stitches are more even and the tension more regular when I'm using evenweave- there's more give to the fabric so you have a little bit more room to move. There are advantages and disavantages to both though, for example it's often easier for beginners to start on aida until they get used to counting out threads to pilot stitches, and of course aida is cheaper.
Why not just buy a little scrap of each and try a little bit for yourself? You'll soon decide which one you want to work with!
So it's referring to how many threads of the color you have in your needle? Ohhhh...!
Two over two...! I get it now! *g* Okay. Thanks!
The trick would be finding a place to get those scraps from. -.- I live in the middle of the mountains and the closest place with any cross-stitch supplies barely has anything decent. But I'll look. Thank you again!