I think a matte flat black would probably look best IMO. I would do a satin though for the white.

I think your bathroom will look amazing but are you not afraid of having moisture issues. We once had a mid tone color bathroom and when we showered the water marks on the walls from the humidity showed even when it was dry I read somewhere that you shouldnt use dark deep colors in bathrooms for that reason.

Thanks roseabbey,
I never thought of that also. We do have a very good fan and a window so maybe it will be OK. If not it is such a small area that we could repaint at any time. Probably not more than 35 SF of black paint.

I just love black rooms as I've said a million times on here. I have matte black wainscotting in my living room and kitchen and thinking about doing the inside of my bookcases black.

Your bathroom should look fabulous black, if you have plenty of natural light or white crown moldings.

I did the opposite in my powder room - I have black bead board on the bottom and an off white paint on the top. Bead board paint is satin, wall paint is B/M matte - not as flat as flat but no sheen like eggshell and washable enough for our purposes. We've used it in several rooms now and like it a lot.

Thanks for the encouraging words everyone, I think we will do it.
Looking at BM aura bath and spa paint in matte.
Because I have so little to do, I think I need a quart only.

If there is a shower, don't use matte. I have semi-gloss dark green in the master bath shower/toilet room and yes, there are marks from moisture and I have a powerful vent fan.

If no shower, then eggshell is best with maybe satin or semi-gloss on wainscotting. I'm not a fan of matte because it is virtually impossible to keep pristine especially with dark colors. One touch of the finger and you need to repaint. No thanks.

As with all things paint and color, you have to match the right product to the project.

Dark color in a bathroom is not a problem with modern formulations. Aura Matte for Bathroom and Spa in black is the best choice for what you are wanting to do.

Streaks can/will materialize with many of the modern-day paints as surfacants 'work their way out' of the paint film. It is called Water Whitening and it usually goes away on its own unless there is something fundamentally wrong with the paint or the grade of paint is sub-standard.

Most people think that it has something to do with the gloss level. It does not. Water Whitening with the modern formulas happens across all sheen levels and all colors. Sometimes it's the higher gloss levels that show the streaks the "whitest". The matte finishes can actually diffuse the streaking somewhat -- it depends.

It's simply more noticeable with darker colors than it is with lighter colors; other factors play into why some colors seem to show moisture streaks (water whitening) more than others.

As far as burnishing, that is most often a condition of using inexpensive grades of paint in a dark color. If you want dark and uber dark, it will cost ya. Aura with its ColorLock technology means burnishing isn't going to happen  it is also why it costs 60 bucks a gallon.

With paint, you get exactly what you pay for. There are no bargains.

I believe there is more information on Water whitening on the Paint Quality Institute's website. I haven't looked for it for a while.

Don't be misconfused. Darker paints with a clear base has to rely on the colorants for hiding; but at the same time will need to bond with the binder when the evaporation process has started. It's not like a person is using a tint base with lots of Titanium Dioxide. From what I understand from my BM dealer, the Bath&Spa was formulated just for "moisture issues" and is definitely a better paint in baths than the Aura Matte.

You mentioned "no small children", a very small area, and good ventilation. This is a true +. One of the things I hear other painters talk about from their customers are the fact they have ventilation, but rarely use it when in the shower. Well as mentioned with different grades of paint machine colorants and different grades of tint bases, streaking with darker colors and burnishing issues *can and will* happen. I know Aura matte has left burnishing issues for me in a foyer before (Black was used). In this instance another decorative finish was going on top so no future issues. Two things it is really best to make sure any dark tinted paints have had time to go through their coalescing stage and securely cured before any type of cleaning is done to the walls & it is really a good idea to use the softest cleaning cloth or a very very soft sponge to lightly dab any cleaning one might have. No paint finish will withstand vigorous cleaning. Paint companies take their products through moisture tests to make sure they pass what the industry standards are. Sounds like in your instance, you have a sound condition. At least you will be using all waterborne acrylic paint tints verses the glycol based paint tints.

For deep tinted bases especially where *ORGANIC* tints are used in certain paint colors, I much prefer to use Aura matte (ONLY when there isn't any possibility of people rubbing or touching walls). If so, I will try and advise to use the eggshell. A much better choice. Aura matte has it's place for use, you just need to know what room and how much use the room will get. You do have a better degree of hardness (eggshell) and IMO the sheen is right on. No angular issues at all.

So, JMHO I would choose the Aura Bath&Spa (the formulated paint for better moisture control and possible surfactant leaching). The proprietary resins from the gennex waterborne colorants should be fine with the Bath&Spa paint.
Anyway good luck with your choice. Oh & I do think there is a little more smell to using. Maybe because I have used it in a more confined space (smaller baths). good luck.

funcolors and decorativewalls:
Thank you both for that very informative information.
I had never heard of the Paint Quality website and found it very interesting.
I am sure that if we go ahead with this I will be using BM Bath & Spa paint so I do appreciate having your endorsement.
You both seem to know so much about paint and its uses that I do thank you for your great advice.

I painted a bathroom black in 2001 (through 2005 when Katrina got it). It was beautiful...I had wide base boards, crown moulding and solid core 4 paneled doors that were painted white. The floor was small black and white 1930s style tiles. All fixtures were white. It was stunning...really...I got compliments all the time. I used a Satin true black (no green or blue undertones). I'm not a fan of matte for lots of reasons...mostly it just screams when there are any imperfections and it's not as easy to keep clean. Anyway...keep us posted...I think it will be beautiful.

I didn't use a true satin paint...but used the BM paint that has the least sheen without being matte. I can't remember now what that was. The sheen was not noticeable. It really was a beautiful space.