Using Channels - converting to Black and White.

1. Open Image in Photoshop and make a duplicate (save the original work on the duplicate)

2. Go to 'Layer' in the horizontal tool bar:
- New adjustment Layer
-Channel Mixer (Click) -
first window click ok

second window adjust to:
select monochrome x

Then, as a rough guide try this combination:

Red 70%
Green 30%
Blue 20%

Adjust this so that it LOOKS good (how you want it) but aim at the total percentage of colours equalling 100%

3. Add Hue/Saturation Layer
(Go to Layers-New Adjustment Layer - Hue/Saturation - OK)
Click OK
Then go to Layers window and move your HUe/Saturation Layer (click and drag) UNDER the Channel Mixer (so it is closest to the background layer) - double click on the icon(black and white circle) - adjust the saturation.

Converting to Black and White using Layers and Hue/Saturation

First of all go to the 'Window' drop down menu and make sure 'Layers' is selected.

1. Go to Layers (drop down menu)
- New Adjustment Layer
-Hue/Saturation

Click OK to New Layer window.

2. In the nex window to open up 'Hue/Saturation' reduce Saturation to -100 (far left) and click ok.

3. Click on 'Background' in Layers palette.

4. Go to Layer on drop down menu (again) and
-New Adjustment Layer
- Hue/Saturation
-In 'Mode:' change 'Normal' to 'color' (close to the bottom).

5. In Hue/Saturation window click OK

6. In Layer's window double clikc on the bottom hue/saturation layer's icon.

7. In this window change the 'master' drop down menu first to 'red' and adjust, then to 'green' and adjust then to 'blue' and adjust.
Click ok when you've done.

This will now be a psd file (Photoshop document) which takes up a lot of memory. If you want you can save it like that and then do a duplicate and go to the Layers window and 'merge layers' then save as a jpg. Or simply save as a jpg in the first place but then you won't have an original.