There are quite a few techniques you can use to convert a colour image to black and white in Photoshop. In past tutorials I’ve looked at converting to black and white using calculations but today I’m looking at using a desaturating adjustment layer to go from colour to black and white. Desaturating literally means removing colour
The advantages of this particular method are that it’s fast and easy and because the changes are happening through an adjustment layer, there is no destruction of pixels, we’re still working in RGB and because it’s happening on a layer we can take advantage of opacity and blending modes.
So before we get into the nitty gritty let’s quickly look at two other ways to desaturated an image.
1. .Choose Image > Adjustments > Desaturate.
That’s really quick and easy but you really have very little control over the conversion and it tends to look flat and there’s pretty much no contrast left.
2. Choose Image > Adjustments > Hue Saturation
This opens up the Hue Saturation dialog box. To completely desaturate the image of all colour, leave Edit as “Master” and drag the Saturation slider all the way to the left. Again this leaves the image looking pretty flat and as with the other method the original pixels have been changed. However you can make changes to the Hue, Saturation and Lightness using the sliders and also specify which colours you want to edit.
Now I’m going to use the Hue Saturation again, but this time I’m setting it up as an adjustment layer. Click on the New Adjustment layer icon at the bottom of the layers palette and choose Hue Saturation.
When the dialog box opens, click OK to accept the settings without any changes.
Change the blending mode to Color for this new adjustment layer.
Add another adjustment layer and again choose Hue Saturation from the menu. Drag the Saturation slider to the left, all the way to -100 so that the image is completely desaturated, then click OK.
Ok so it still looks a bit dead and lacking in contrast, but the trick now is to go back to our first adjustment layer – the one with the blending mode set to colour and double click on the adjustment layer thumbnail.
The dialog Hue/Saturation dialog box opens again. This time drag the Hue slider – you will see instant results as you drag the slider to the left and right.
The image is already looking much better.
To add some extra oomph and finish up, select the Color mode adjustment layer (this should be below the normal mode adjustment layer) and duplicate it by clicking and dragging the layer down to the new layer button at the bottom of the Layers palette.
Reduce the opacity on the new layer to about 55% – this will vary depending on your image. So my final black and white image looks like this;