Yes you can, but the coverage will be extremely blotchy, the paint will be runny and drippy on the walls, and you will be really unhappy with the resulting mess.

If you try to stretch the paint by pushing real hard on the roller to squeeze out every drop of paint, you are guaranteed blotchy color.

even with just a tiny bit?

I was re-thinking the math and taking a close look at my leftover amount (which I can add to the job too, the color difference will be negligible). Technically, I should have enough based on the first job usage. That's how close it is.

I have some BM extender (used for Aura wet edge improvement) that says it can be used for Regal. Doesn't an extender thin it out that would help stretch it also?

The ONLY thing an "Extender" does is "relax" the paints' binder-resin, so that it doesn't set up so quickly.
* This gives paint more working-time, and helps leveling.
* Extenders also enable exterior painters to paint in warmer weather, when paint would ordinarily dry too quickly...
* A good one is XIM's Latex X-tender. I've got it where I work. Many SW shops have this too. You'll have to call around....

Don't go the "added water" route!
>>> Sure...you'll have more "paint"....BUT...it'll be a thinned-out paint with less integrity the more water you put in.
>>> Think of putting water into your favorite pancake batter to get more pancakes!! You KNOW what'll happen then...!

Faron

I agree. Adding water will not extend your amount of paint. And, you won't be able to cover up the previous color efficiently.
The only time I would add water is for a decorative treatment, i.e a glazing. But for a solid, it's not wise. The pancake analogy is perfect!

You seem determined to do this. If you read the can, it says "Thinning is unnecessary, but if required to obtain desired application properties, a small amount of clean water may be added."

But really, is an ounce or two of water going to solve your problem? Better to figure out where you will have furniture covering the walls and not do a second coat in those areas. Or consider an accent wall in a different or deeper shade of what you have and skip one wall altogether.

But really, it's a shame to do the work and then risk it all at the end.

But really, is an ounce or two of water going to solve your problem?

I don't know. thats why I was asking.

In the meantime, my trigger thumb has flared up (probably from all the sanding and painting over the weekend -
), so I am on hold.

Its a bathroom so not much furniture or obstacles involved. An accent wall is a good idea, but not really sure about that in this room. I will probably leave the door wall til last just in case. There's not too much surface on that wall to save a lot, but at least its not visible when you first walk in the wall.

Although on 2nd thought maybe the vanity wall might make a good accent wall.. hmmm... something to think about. I'll see how the other two walls go and try to assess mid-way which wall goes last.

Thanks for all your inputs.

duh... can I say proofread

"...walk in the room"... not wall

Just to wrap up...

With really scraping the contents of the cans and previous batch leftovers into my mixing bucket, I ended up with just under 1.5 qts of paint. I added a couple of splashes (1/4 cup or less) of water and mixed thoroughly. I applied generously (confident I had a backup plan). No drips. No blotches. I ended up with plenty of paint for all walls with about 1/3 qt leftover.

Unfortunately, I can't say if the splashes of water helped spreadability/stretchability or not. I think so, but its not scientific.

YMMV.

p.s. Ironically, my color recipe (4 parts nimbus gray @ 50% lighter to approximately 1 part Paradiso) absolutely is dead on with Wedgewood Gray. That chip was in my chip stash, but I started out thinking I was not going to go that light. Amazing how these color choices evolve...

Now on to accessorizing... so much more fun!