How to Create a Black and White High Contrast Sky from a Colour Image

How to Create a Black and White High Contrast Sky from a Colour Image

Final SmallIn this Post Scott Wylie shares how he creates dreamy black and white skies in landscapes.

In this article I’ll show you how to take a colour landscape image with white clouds against a blue sky and convert it into a black and white image with a high contrast sky using Adobe Photoshop CS4.

We will use the channel mixer to control which colour channels are mixed into the black and white image, and levels to produce the high contrast dream-like effect which is similar to the images you may have seen from Infra-Red photography.

When I was shooting on film I would often use a red or orange filter over the lens, these filters don’t allow much blue light through and so blue areas of the image look quite dark, we can create a similar affect in Photoshop by using the channel mixer to convert a colour image to greyscale.

Here is our starting image:

Clouds And Fields 19-07-2008 048 Start

This dull image was taken in poor light and I wouldn’t consider presenting it but with a good black and white conversion we can create something really dramatic from it. I often use a polarizing filter to saturate blue skies and in this image you can see that the sky darkens gradually towards the top of the image as a result of the filter. This will help us to push the contrast further in the post processing stage.

Step 1:

Rather than just desaturating the image or converting to greyscale, we will use the channel mixer to blend the three colour channels into a greyscale image. If we use a lot of red by setting the value to around 110%, no green by leaving it at 0% and we subtract some blue by setting it at -10% we create a black and white mix in which the blue sky is darkened against the white clouds. The total across the three channels should add up to 100%, any less and the image will be darker, any more and the highlights may become blown.

Channel Mixer

When using the channel mixer, take care not to subtract too much of any colour channel because the result will look very unnatural and often creates a very noticeable ‘halo’ around parts of the image. -10% is probably as low as we can get away with without things looking over-processed.

Step 2:

When we’ve created the black and white mix the next stage is to select the sky area, this is because we want to be able to push the contrast as far as possible in the sky without losing highlight/shadow detail in the ground. To do this, use the magnetic lasso tool to select the sky.

Select And Feather

It’s important to feather the selection so that any changes we make are blended into the non-selected area, if we don’t feather then there will be a very obvious border between the two. As a rule of thumb I usually set the feather radius to around 10-20% of the number of pixels along the longest edge of the image.

Step 3:

Using the levels control, we adjust the contrast in the selected area until we’re happy with the result. If the black point is set too high then the dark sky will begin to look pixelated, if we set the white point too low then the highlights in the clouds will become blown out.

It’s a good idea too see how far things can be pushed by doing an auto-contrast adjustment, see how it looks and then undo it and use the levels control – any more contrast than this will definitely blow the highlights and lose shadow detail making things look very unnatural. The best result is usually gained by using a little less contrast than the auto feature produces.

Levels

Step 4:

After setting the levels on the sky, we invert the selection and do the same for the ground.

The final image looks like this:

Clouds And Fields 19-07-2008 048 Final Small

Here’s another example where I’ve taken a colour shot and created a dream-like black and white image from it.

Before:

Start Small

After:

Final Small

Scott Wylie is from England and likes to photograph abandoned or curious places and use light to produce dynamic and interesting images of people. See more of Scott’s work at www.scottwylie.co.uk.

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Some Older Comments

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  • Macro Photography April 21, 2009 05:07 am

    This is amazing. I can't wait to get my pictures around to try this out.

  • Barry Finlay April 17, 2009 07:26 pm

    Great tutorial. I live and photograph in Scotland where a lot of the time I am working with poor dull lighting. This will be a great way to make some would be dull boring pgotographs into more interesting images. Thanks.

  • carolbrowne April 16, 2009 04:04 pm

    Great tutorial. I tried it on one my photos and then ran a sepia action over it. I really like the results. Thanks so much!

  • Fl├ívio Demarchi April 16, 2009 08:09 am

    The only problem with this method is the noise. Boosting the red channel usually results in noisy tones over the blue areas. An example: http://www.flickr.com/photos/flaviodemarchi/3261133738/ (see it large)
    Lens filters still are the best option for black and white. ; ]

  • Fletch April 16, 2009 02:07 am

    It can be done in PSE as well.

    http://jfletcherphoto.wordpress.com/2009/03/13/photoshop-elements-tutorial-converting-to-black-and-white/

  • ImgSensors April 16, 2009 12:39 am

    Thanks! Love the result. I'll sure give it a try.

  • ThomasK April 16, 2009 12:32 am

    Thanks for this very usefull article!

  • cristiano007 April 15, 2009 11:17 pm

    Interesting tutorial. I just think that the initial image is not dull at all.

  • dcclark April 15, 2009 10:19 pm

    This will work quite well in GIMP. In fact, in GIMP you can choose "Preserve Luminescence" in the Channel Mixer dialog, to have it automatically scale your channel percentages to total to 100% -- that avoids the problem mentioned at the bottom of step #1.

  • Jeffrey Kontur April 15, 2009 09:48 pm

    I love that there are so many ways to do more or less the same thing. Each result is slightly different. That's precisely what makes Photoshop the gold standard.

  • Scott April 15, 2009 09:02 pm

    You can certainly achieve the same effect using the black and white adjustment, however it's still necessary to create the mask otherwise the borders between the sky and bulidings etc will have a very unnatural halo if you adjust for a really dark sky. Secondly, using the channel mixer (which doesn't allow you to just click and drag parts of the image lighter/darker) requires the user to think about how the colours are being mixed and I feel an understanding of this is very useful especially when choosing subjects at the shooting stage.

  • Ali April 15, 2009 05:27 pm

    Thanks

  • johnny April 15, 2009 04:43 pm

    I use GIMP and I believe this gonna help me.

  • Reznor April 15, 2009 10:48 am

    I don't see why you would use the channel mixer in CS4 and not just a black and white adjustment layer. Gives you much more and easier control, you can just click into the blue of the sky and drag the slider till it's as dark as you wanna go.