How do you keep part of a photo black and white, and another part coloured?

[Elwyn]

This has been confusing me....

[Andantonius]

this tutorial pretty much covers it.

[xC4RN4G3x]

its basically using ur brush in saturation mode. paint black or white depending on where u want color, etc.

[SickBoy!]

You can also select the coluored parts, inverse the selection and go to Hue/saturation settings and turn saturation down...

[J.C PHOTOGRAPHY]

thannks for this i just used to desat the whole picture n use the history brush on the sections i want coloured

[Cheer Mom]

I used the eraser and it undid the desaturation. I guess there are a few different ways to get the same result.

[Trigona]

From my experience, the fastest way to do this in PhotoShop is to press
Ctrl+J (Duplicate layer) with the colour layer selected, and then with the layer copy selected, press Ctrl+U (Desaturate) after that, I just erase the parts I want to have coloured. Just switch the order of the layers and eras if you want it the other way around (i.e. you want to just have a part of the image in B/W).

[pshopper]

If you have Photoshop, it's dead easy. Create a new channel mixer adjustment layer, making sure to tick the 'greyscale' box to get a B&W effect. Then, with the new layer active, just erase out the bits you don't want to be in B&W, like you are scratching away at the top layer to reveal the colour underneath. If you make a slip, you can undo (ctrl-Z is quickest) or you can use the brush tool to go over the mistake.

Hope that helps.