3 methods to convert a colour photo into a black-and-white image

The Channel Mixer is typically used for color adjustments. But if you click on the Monochrome option in the dialogue box, the result will be gray-scale. Then use the Source Channels slider bars to determine how much data each color channel will contribute to the final image. Click on OK when you are satisfied with the results.

• Click on Create new fill or adjustment layer and select Channel Mixer...

• Check Monochrome

• Move slider bars to adjust each channel

You can maintain the image as a layered RGB file, so you can return to the Channel Mixer layer to make further adjustments. You can also use the Image > Mode command to convert the image to gray-scale when you're ready. Photoshop will automatically apply the adjustment layer and combine the layers into one file.

You can also duplicate background layer and change the blending mode of the new layer to Hard Light (to increase contrast), Multiply (to darken the image), or Screen (to lighten the image).

This allows you to choose two channels (darker and lighter) from the image that you can blend together to create a new channel.

• Click on the Red Channel in the Source 1 Channel pop-up menu and then choose Green in the Source 2 Channel pop-up menu.

• Set  the Blending Mode to Multiply or Lighten, and lower Opacity if necessary.

• At the bottom of the Dialog box, select the Result pop-up menu and choose New Document and click OK.

• Image>Mode and choose Grayscale.

1. Image>Mode>Lab Colour
2. Click on the Lightness channel in the Channels palette
3. Image > Mode > Grayscale and click OK
4. Click on the Layers palette and duplicate the background layer
5. Change the Blanding Mode to Multiply and lower Opacity if needed