I think you're right. I wouldn't whitewash or paint it.

Can we see more of the room to give better suggestions?

The problem isn't the brick it is the brass surround and the different color mortar. Why is the mortar different colors?

hammer it

Ellsworth I think you are right. It is shadows after a closer look. I think someone painted the mortar white and since the mortar is so recessed it is causing a shadow. If you look closely at the brick you will see a little bit paint on the brick.

If it was me I would repaint the mortar the same color as the mortar in the slate hearth. You are never going to get the paint off of the mortar.

paint it. get a heavy duty brush (not an expensive one) and paint. you have to daub to get those grooves. It's going to take multiple coats. brick sucks up paint big time. you can prime first if you want, but it's still going to take a few coats.

I'd paint it black. love black brick w/a wood mantle

remove the gold insert, and get the rustoleum matte black heat proof spray. and there are tons of how -to's for this and painting the brick, online.

Yes, you can paint it and get the paint in the grooves. It's a PITA job, not fun. You could also grout the grooves first and then paint it. Might be easier to tile over it, paint the metal black and do something cool with the mantle.

Yes, thank you everyone who responded so far ... I do intend to get rid of the brass and go with black . Just trying to figure out what to put there

i have considered maybe putting tile colored brick tile over the brick I

Consider German Mortar Smear technique instead of whitewash or limewash

Personally I am not a fan of whitewashing or German schmear when going over red brick. Then it looks pink which I think is even worse.

Maybe spraying would be better than using a brush or sponge, to get into the grooves. It's suggested here. https://www.bobvila.com/articles/how-to-paint-brick/#.WkhBnnlG3g8

Yes, like German Shmear and/or adding grout into the recessed crevices to bring the brick/mortar flush. Will require a special grout bag (ala a pastry bag) to get in there, and fireplace will then become more classic- less dated look.

Well , I come at that with a dremel tool and a sander ; take on them grooves till its all a solid surface and then white wash that all up. Will need a mask, I reckon. Plastic in the door ways and helper with a wet dry vac keeping all the air particulate to a limit.

Ellsworth and part I'm if you are referring to my post/ picture ( sorry still trying to figure this out). The mortar was white I painted it light grey trying to improve the look it is all the same color

You can tile right over a brick fireplace. More expensive than just painting it but you'll have something you enjoy. Gray tile is popular now so you will have a good selection. Choose a tile that looks good with your slate hearth.

https://www.thisoldhouse.com/how-to/tile-over-brick-fireplace

I would have a painter come & look at it. It took me years to have my brick painted; however, I am so happy with the outcome!

So what did you do? I am facing the same problem with the same brick.

Still thinking about it.. I'm really afraid to paint it I. Case I don't like it

I am thinking of finding some kind of premixed mortar or the brick equivalent of spackle and just fill in the grooves. I may have less sq ft than you, but I think I can do that in an evening. Not sure what to use yet - something gray would be great. Smooth the bricks imperfectly. Then whitewash

Whatever you decide to do on the brick, paint the brass fireplace surround to black. You can do it while you're deciding.