I don't know about sanding and painting. I have removed many popcorn ceilings and the process is something like this:
Scrape ceiling
Sponge off dust
Two layers of skim coating
Sand
Prime and paint

Unless painted, most acoustic,(popcorn), ceilings come off pretty clean by dampening the ceiling using a garden sprayer. It scrapes off clean with the exception of the drywall seams where they have been mudded. Minimal sanding in those areas is typically required. Too late for that now, so you might still consider dampening the remaining product to loosen the rest of the product, skim coat and feather over the seams areas. The acoustic sticks to mudded areas better than the bare drywall areas when sprayed, that's why more effort and attention is needed in the mudded areas. The above process works well but is a tad more work. If the rest comes off relativeley easy and you feather out the seam/mudded areas, a final skim coat over the entire lid will give you a more consistent surface if you are gioing for a smooth finish. If texturing, then the final skim coat isn't necessary. Primer followed by two top coats of finish with a quality paint such as sherwin williams or benjamin moore.

Hello scarlett2001 and congratulations on removing the popcorn ceiling! It takes a lot of gumption to remove the popcorn.

Don 92 and sieraeast are right. There will be more scraping, sponging, sanding, skimming, sanding, priming, and painting in your future. But at least each step will be one step closer to the end result. Plus you will be able to see positive results.

I recommend using a pole sander to sand the ceiling. Please use a respirator, keep the plastic on the floor, and vacuum often. Since there is dust throughout the house, please take a time-out and clean everything to get the dust level down to avoid inhaling or ingesting anything harmful. Consider putting up plastic sheets or old bed sheets to keep the room separated from the rest of the house to minimize further dusting. Be sure to change out your air filter since it will be working overtime to remove the particulate matter throughout the house.

Best wishes and please keep us posted on your progress.

While sanding or scraping, seal off the room except for an air entrance on one side and an exhaust fan to the outside on the other, thus creating a through-breeze that will carry out a lot of the dust.

scarlett-
I hear you that you're not concerned about asbestos-related disease, so I'm not going to lecture you.

However, for others who are considering removing popcorn ceilings and are the least concerned about potentially contaminating your house with asbestos and causing health risks for your family, please don't do anything before having the material tested first. And if your ceiling is positive for asbestos, you should either get professional removal assistance or do it yourself using safe removal procedures (which the above are definitely not). The link below provides some useful info on what's involved.

Here is a link that might be useful: Popcorn ceiling removal

Typically asbestos was banned in acoustic celing products in the seventies, but warehouses often kept asbestos laced products in the mainstream well into the eightiies, so even if your house was built in the eighties, there's still a chance for asbestos laced products. Good heads up warning by Kudzu9!

Yeah, I hear you. I wore a mask (not a respirator) and am now coughing up stuff. This was not one of my better ideas.

"I wore a mask (not a respirator) and am now coughing up stuff. "

A typical 'nuisance' dust mask is not very effective against drywall dust.

The powder is so fine in goes through the mask (and many vacuum filters).

Yep, hindsight is 20/20.
And yet, the guy who wanted the $600 was not going to do anything different than I did. That's why "we" chose to do it "myself". I guess he would have gone by the Home Cheapo and picked up some undocumented workers to do it. And paid them minimum wage or less.

How does DH get away with that?? Mine would lose his "D" after a trick like that! Seems to me that if the first pass was your job, the next pass is his - be it scraping, painting, or sanding.

But if it were me - let's say, DH is so busy cooking, doing dishes, and sewing curtains that he can't pitch in - I wouldn't sand for anything. There is a limit, and I have degenerative disc disease in my neck just from painting ceilings. I'd dampen and scrape as smooth as it would go (since dampening is how you mitigate the asbestos risk anyway), and getting that to work would involve finding the right scraper. This might be a cabinet-scraper type of thing, or a pull scraper of some kind, Depends how you work best. Then I'd paint and be done with it, or maybe at a pinch I'd put some filler up to smooth it out. But no sanding, no way, no how.

Then I'd paint with whatever required the fewest coats. (I was painting the last ceiling red, and it took about 8 coats to cover before I learned to put grey primer underneath).

But as you can probably tell, I'll quite happily take a rustic finish over doing obsessive work overhead. I limit my obsessiveness to vertical surfaces or those that are underfoot. But, not everyone feels this way.

Sierraeast, I'm encouraged by your info to hope that the popcorn ceilings in our basement might not have asbestos... need to get tested, but I was wondering whether to bother. Thanks!

Hang in there, Scarlett.

KarinL