How do you white wash a photo?

I'm guessing you're talking about the flare effect behind of the woman? It's difficult to guess how much was created in PS and how much is part of the original photo.

To recreate this using the woman and the curtains you'd need to cut her out and paint a white glow in the layers in-between, using layers blending modes to soften and make it look realistic.

 

just create a new layer of pure white, then turn the opacity down to like 4 - 5%

 

Brightness/Contrast can accomplish that as well..

 

either create a layer filled with white and adjust the opacity.

Or in levels (image> adjustments> levels) move the left marker on the output levels slider to about 10.

 

It might be helpful to see what the original looked like so there is some basis for comparison

 

Adjust the curves so the darkest blacks turn to gray. With the curve window open you can click on the picture to tell which value is where on the curve so you can adjust specific values without messing up other values.

I made the effect more extreme by just moving the bottom point diagonally up, you can also play with it more by adding more points and bending the curve so its more contrasty in the red or whatever.

 

Definitely curves!

 

I dont know, you just go to image>adjustments>curves and move the bottom left point up along the diagonal line. His version has a lot of blue so he probably picked the blue channel from the drop down menu and messed with that the most. You can give it a colored tone by doing the channels individually, or give it an even gray tone by doing RGB.