Converting Color Photo to Greyscale [Method 2]

1. Open photo.
2. On the Layers palette, click the create new Adjustment Layer> Channel Mixer.Click [OK]
3. Tick the Monochrome check box.
4. Adjust the Source Channel slider RGB to create the grey scale image.

Converting Color Photo to Greyscale [Method 1]

1. Open photo.
   
2. Go to >Image>Mode>Lab Color.
3. Go to Channels palette. Select Lightness channel.
4. Go to Image>Mode>Greyscale.
5. Click [OK] to discard the other channels.