Photoshop
Tutorial
Tutorial #14
Converting to Monochrome with the Black & White Adjustment Tool
A monochrome image can sometimes convey more emotion and be more thought-provoking that one in glorious technicolour. It seems that sometimes the colour 'gets in the way' and destroys the original intention of the photograph.
However, not all photographs work with the colour removed and it is not a foolproof method of rescuing a failed colour image. In fact, it is far better if you go out and take the image specifically for a monochrome conversion rather than just trawling through your files in the hope of finding one that works.
So what makes a good image for conversion? Tonal range. You need an image showing a vast range between the darkest parts and the lightest.
Once you have your image then there are various ways of converting it into monochrome. Many digital cameras have a 'black & white' setting which will convert an image in-camera but the drawback is that you have little control on how the final image looks. Similarly many RAW editors e.g. Lightroom, have a check-box which will convert to monochrome but the same problem applies.
Until recently the most common controllable conversion method with Photoshop was to use a Channel Mixer Adjustment Layer which provides a check-box to convert to monochrome and three sliders to control the output. However, since version CS3, there is now a Black & White Adjustment Layer that includes 6 sliders to give much more precise control over the result.
Here is an image of a victorian merry-go-round. The age of the subject matter means that it is ripe for a monochrome conversion and there is a good tonal range throughout, particularly in the sky. As a colour image it simply doesn't work mainly due to the clash of the blue sky and the turquoise of the fairground.
Open the image and click the Black & White Adjustment Layer button.
You will see a new adjustment layer panel appear on the right with 6 colour sliders. The image will also have lost all of its colour.
You will notice that at the top of the adjustment panel there is a drop-down box with various presets and also an 'auto' button beneath it. Whilst the presets and auto options sometimes work very well the purpose of this tutorial is to provide you with the knowledge to make the decisions yourself - so we will ignore them.
Adjust the positions of the sliders in turn to create to desired output. Each slider allows you to adjust the tone of the specific colour components in the image. Since I usually take landscape-type shots that include some sky I tend to start with adjusting the Blue and then Cyan sliders to create a nice sky before altering any of the others.
First adjust the Blue slider. If you slide left then the blues in the image go darker and conversely if you slide right then they get lighter. You will see that all the sliders range from -200 to +300 but the extreme end can produce a lot of noise so I tend to try and keep the sliders within the range of -100 to +150. We need to darken the blue in the sky to create contrast with the white cloud so slide it to -65.
Although it has darkened a bit it still needs more so reduce the Cyan level to -65 also.
Continuing up the slider list to adjust the Green. The turquoise panels on the awning and the merry-go-round cabin need darkening so slide this down to -100.
The trees in the background were already very dark and moving the Green slider to the left hasn't helped. However, you will find that the Yellow slider is particularly good for brightening up foliage. Here we have gone up as far as +130.
Now we just need to lighten the buildings brickwork on the right so slide the Red slider slightly to +56.
Finally we come to the Magenta slider. I have yet to find an image where this slider has any major impact but for completeness slide it up and down to see what effect, if any, it has. Here a -100 value just makes the left-hand merry-go-round chairs have a bit more tone.
So here is the adjusted image:
Finally it would be better if the attention was focused on the merry-go-round rather than being distracted by the building on the left and right. To do this we are going to create a slight vignetting effect:
Merge the layers together (Layer -> Flatten Image). Then select the Elliptical Marquee selection tool.
Draw an ellipse centering on the merry-go-round cabin. Choose a Feather setting of about 150 pixels.
At present the 'active' part of the selection is the centre of the ellipse - but we want to adjust the outside so choose 'Select' ->'Inverse' to make the outside of the ellipse active.
Top Tip !
By default, the centre of any selection is the active part. To invert this so that the outside of the selection is active choose 'Select' -> 'Inverse' or alternatively press 'Ctrl-Shift-I'
Now create an Exposure Adjustment Layer.
Now reduce the Exposure slider slightly to darken the edges of the image.
So here is the final image after all the adjustments:
Roll mouse over image to see the unadjusted version
In the next tutorial we will look at the most useful Blending Modes for landscape photographers.
If this tutorial was useful to you, please let me know by signing the guestbook. Thanks.
Print this tutorial out as a PDF document
All material on this web-site is copyright
© John Hallett 2008-2010
