A cover that works well in greyscale runs the risk of being rather bland and simple in colour. One technique to ensure that the cover remains interesting in colour is employed effectively by Beasts of the Walking City. The cover is mostly black and white, so the skyscrapers and the cat eyes are clear in both colour and greyscale. The dark text stands out clearly against the light background. This is a cover that works well in greyscale. In colour, the green highlights have been added to the eyes and to the text. Eyes are often an arresting image that draw the attention and the green only adds to this effect. The colour adds to the impact of the image, without doing anything to make it confusing in grey.
The cover of The Magpies does the best job of working in both colour and greyscale. In colour the entire cover is in shades of blue. The darkblue of the ground, the trees and the title, compared with the light blue of the mist, the girl’s dress and the water, fading to white behind the title. The authors name is also in white. The only other colour is the pink flesh of the girl. The contrast between her pink skin and the blue background makes helps to make her the focal point. This colour palette does a brilliant job of evoking a sinister and melancholy mood; it highlights the helpless solitude evoked by her pose.
In greyscale the mood of the blue is lost. The subtle variations in shade become a wash of grey. The contrast between the blue background and the pink girl is lost in the grey. The picture loses a great deal of its detail and and seems flattened. However, the contrast between the dark text of the title and the light background becomes more effective. The title really stands out in the greyscale. Likewise, the small white text of the authors name is rather lost in the similar shades of the colour cover. In greyscale, the name is clear and highlighted by the contrast.
In the colour version the cover had mood and a focus on the image. In the greyscale version the focus is on the title which stands out to the reader. Both covers work well, but differently.
Edited to add: After I published this post I looked at the two images of The Magpies above and thought that they did nothing to support my argument. They both have clear text and image, the image isn’t clearer in colour, neither is the text clearer in greyscale. Please look at the A3 book covers charts. When you view these covers in thumbnail, competing against a host of other covers for your attention, then you get a better idea of how they stand out.