Focus on the light blue, not the bright pink. If the reason you are using primer is solely color, it's smarter to focus on priming to support the new color so it comes out a fab final finish vs. priming for the purpose of covering up the old. Focus on the new, not the old.

Go to a professional paint store and choose your blue. Ask the pros at the store what you need to do to prep the walls to support your new color. If you're buying top tier paint and it's the right color (a blue that covers well), you might not have to prime at all.

But you need to ask.

Also, I'm assuming you do not need to prime the walls for any other reason than you think you need to 'cover up' the existing color.

do as fun says
surely avoid all of those Kilz products

My painter already said that I need a primer to cover up the awful color already there.

The blue we already have, it is the color of the walls in the living room paint, and the former owners left this extra paint.

Ugh...see, even the painters help to keep the popular misconceptions alive! A primers job is not to cover up old ugly colors. It's job is to seal and provide a nice base for the next layers of paint. Questions like this are difficult because we don't want to deter people from using primers and I'm sure your painter would love to charge you some extra money because he seems to think it's required, but if the primary concern is covering up a color then a primer is not needed like the others have said. If the new color is some horribly covering kind of light blue, then I would possible prime with white to at least get the transformation headed in the right direction, but it depends on the blue...some cover well and some do not and also depends on the size of the bathroom...if it takes me 12 minutes to roll on a coat of paint, would it really be worth it to break out some primer or just use the paint?

No one has really answered the question that was posed, which is whether a special primer is needed for an extreme color change. In my just-a-DIYer opinion, no, you don't need a special primer.

But if it were my house, I would apply a coat of primer. It is cheap insurance that you will need fewer coats of the blue paint. You can't go wrong using the primer whereas you may regret not using it.

Couple things I didn't see mentioned here....

Since it's a Bathroom-
WASH the walls first with POWDERED Dirtex.

1) Since final color will (almost certainly) go into a White-base, it's the most opaque. Blue colorant into a white-base DOESN'T make it less opaque. This also assumes that the paint isn't being pushed too thin, &/or applied with crappy tools. 2 coats of Lt.-Blue may be enough IF done right.

2) AGE of walls/existing paint...
* If it's been a decade since the last paint-job....prime.
* If numerous repairs/spot re-texturing are involved....prime AFTER all that's done.

Faron

Thanks for the messages.

The paint that we have is Miller Acro Pure flat medium base Pewter. From what I can tell from the Miller web site, it should do well in a bathroom.

I applied a touch of it on the fuchsia, and the fuchsia was still quite visible through the pewter color. I am concerned that more than one coat may be needed, sans primer.

I guess I will get a primer.

There are dozens of primers in the local hardware store. I have no clue what kind to get. Any advice would be welcome.

Thanks.

Mac

It depends if this is a regular flat paint or a washable flat. It's hard to tell from the website what it is and the technical sheets are not available. A regular flat paint is porous and will absorb moisture and eventually bad things can happen.

I would never use a flat in a bathroom, washable or not, it will still absorb moisture(IMO)
As to a primer, you cannot go wrong with Zinsser 123

The Miller paint folks confirmed that a flat should not go in a bathroom.

I will look for something at the paint store, which also carries Miller paint. The man said gloss or semi-gloss for bathrooms.

Eggshell or satin would be fine, no need at all for semi or God forbid a gloss

I agree with chris.

Sorry to keep being a contrarian here, but I have used flat/matt paint in several bathrooms over the years without problems. I use my shower and/or tub to wash dogs who then get out of the tub and shake water on the walls. The matt paint does not water spot.

Gray, I agree because it does depend on what matte paint you're talking about using. There are grades of matte that work just fine in kitchens and baths.

But you have to be careful because some of the cheaper flats are indeed porous like pg states and it's a mess.

Have a color consultant friend who spec'd Aura Matte for a client's kitchen. Painter switched her spec's and used 'builder's grade' flat (won't mention what it was). Her client came back to her a year later and wanted to hold her liable. After poking around she discovered the painter AND client both agreed to use a lesser grade than what she spec'd. Because the painter said it wouldn't make any difference and it was ridiculous to spend 'that kind of money on a gallon of paint'.

A year later and the woman can't wipe the simplest of splatters off the walls and it looks like hell.

Flat or matte - not all paints and sheens are created equal. Speaking in general terms, not knowing what kind of paint/color expertise readers have access too, maybe the prudent thing to do is to state it as Chris has stated, that eggshell or satin are good choices for a bath. Because even in cheaper grades the homeowner at least has a shot at some degree of durability due to the extra level of gloss found in general across the board in egg and satin.

yea, what she ^ said :)

I am a complete DIY novice on painting-really, it's painful to watch me. Recently after wall prep (TSP, prime around nail holes, fill holes, let dry, gentle sand), I then fully primed a previously painted yellow orange wall bathroom with BM Fresh Start primer. It took me two light coats-I didn't judge the first coat right on amount of primer obviously-for that color to be completely covered over.

However, I am changing to a BM custom made neutral gray white in eggshell where I want absolutely no yellow/orange undertone showing. So to me it was worth the effort. Good luck.

SparklingWater

Just fyi, one coat of primer is all you need

Thanks, cristophen. Yep, you're right. Do you believe I was trying out an "edger"-one of those red rollee things but couldn't figure out how to use it. Let's just say I got the primer on it, but ended up with the brush part coming out of the base and the paint all over my hands. So then I turned to a tapered edge brush, a good one, followed by a good roller. But, I didn't know how much to roll onto the roller, and after doing the W thingy on the wall, I noticed at some point in my up and down rolling I started to take the primer off. Dries fairly quickly.

As I said, painful to watch, even for me. Think I'll watch some you tubes or talk with the guys at the paint store some more. I'll get it the knack of it, don't worry...

My niece's bathroom was painted a bright fuscia. I loved going in there - made my skin glow and my spirit sour. I think I even looked younger in there! : )