Luminosity Blending

A quick but versatile Photoshop technique for selectively bringing out tonal contrast in your photos

For those of you familiar with Photoshop [see Alfie’s note at the foot of the page for alternatives] you might look at the Layers pane and wonder what all the ‘blending modes’ are in the top left corner.  Click on the drop-down menu and an incomprehensible array of selections are available to you: ‘Linear Light’, ‘Multiply’, ‘Screen’, ‘Exclusion’ etc.

So, what the heck do we do with all of these modes?  It turns out that some of them are pretty darn useful if you know a couple of tricks with them. The one I’m going to introduce today is the one down the very bottom (you can’t actually see it in the screen grab above), and it’s called ‘Luminosity’.  It’s a deadset winner for selectively increasing tonal contrast in your photos without changing the colors.

Here’s a couple of photos from a recent workshop we did down at Futako Tamagawa a couple of weeks ago.  Some judiciously applied luminosity blending helps take a photo like this;

to this:

(The clouds might look a little too dramatic but I went a bit overboard to show the effect more clearly)

(Very) simply put according to my shaky Photoshop knowledge, the Luminosity blend mode takes the brightness values of the pixels in the layers above, and applies them to the pixels in the layer below and makes a new resulting color.  So, what we’ll do is create a duplicate layer of the original photo, turn it into b&w and then when we place it above the original layer using luminosity blending the actual colour of the pixels won’t change, only the brightness will. If this doesn’t make sense (and don’t worry if it doesn’t), just follow the steps below.

1. Open your photo in Photoshop. Go to Image -> Duplicate Image to create a separate but identical window of the photo.  We’ll be making that version into a monochrome and editing that one for a bit, while leaving the original colour one to the side.

2. Turn your image into a monochrome version. Although I have Nik’s Silver Efex I still like to use the Channel Mixer adjustment layer to do it quickly and painlessly. Go to Layer -> New Adjustment Layer -> Channel Mixer and click Ok.  Then click the Monochrome checkbox in the bottom left corner of the pop-up and use the sliders to adjust the relative brightnesses of each channel until you’re happy with the state of your B&W image.

3. Now, we’re going to refine the tones even more on our black and white image.  These tones will eventually become part of the tone structure of our final coloured image, so we need to pay close attention to this one as it’s a bit complicated.  In order to do this we need to create a special layer for dodging and burning.  Hold Option (or Alt for PC) and click on the New Layer button in your Layers Palette. This will bring up a New Layer dialog box (pictured below) – change the mode to Soft Light and check the box that says ‘Fill with Soft -Light-neutral color (50% gray)’.  This creates a new layer filled with gray that doesn’t affect your image due to the Soft Light blending being applied.  Using the Dodge and Burn tools on this layer will lighten or darken the underlying image without changing the color or texture.

4. Using the Dodge and Burn tools, give the image some more tonal contrast. Set your Dodge and Burn tools to affect Midtones at first, with about 12-15% exposure and a very soft brush and just progressively brush in areas where you would like to see more contrast. Vary the size of your brush depending on where you are editing – in this case I used large soft brushes for the clouds and small ones to deal with areas on the face and body. You can see the results of my dodging and burning below – each case is different but I lightened Akiko’s skin a little, darkened the shadows on her face and arm slightly and added a bit of contrast to the clouds by selectively dodging and burning.

Your layers palette should look something like this:

5. Once that’s done, flatten the b/w image and drag it over on top of the original color image. Select the blend mode on the top left of the Layers pane, set it to Luminosity and voila – you’re done.  If you need to make final adjustments, you can make them in-situ using the dodge/burn tool or redo them in the separate image and just drag the b/w over again.  A little skin smoothing and bang!  your image is done.  Much more tonal contrast in the skin and sky, and as a result it’s much more pleasing to the eye.

Luminosity blending is a powerful tool for separating color from tonal values and dealing with them separately. Usually if you try and do these things together you’ll end up affecting the other one inadvertently.  Use this technique if you feel your image is a little flat or want total control over the tonal shape of your image. Here’s another example of Luminosity blending being used this time in conjunction with some color adjustments.

Hope you enjoyed this Photoshop tip and found it useful.  More to come in the following weeks.

Note from Alfie:

We are pros and we tell you about stuff we use. But we also make a habit on our lessons of trying – where we can -to let you know about the alternatives. We don’t use all the softwares so it’s difficult to keep up with them and all their features. But we’d encourage you to try out these links for some alternatives and for some work-arounds:

Photoshop Elements supports layers from Version 4.0, so you should be able to do all of this tutorial in Elements if that’s what you are using. Elements doesn’t support ‘Layer Groups’ though, for future reference. Nor does Elements support that other most useful of tools for some of the more advanced editing – Layer Masking – but I found a tip about how to duplicate the effect of Layer Masking in Photoshop Elements here.

The Gimp: an alternative for photo editing. It’s GNU Public License, therefore free. I used it a fair bit from 2002 until about 2005, since when there have obviously been updates. It is OK. If you have used Photoshop of any kind, Elements or the full version, you will find the GIMP frustrating.

Splashup: a nicely featured photo editing tool that lives online and that you use online. Very worth checking out and especially useful if you are on the roam and don’t have your usual editing tools to hand.

About Japanorama

Japanorama is run by British professional photographer, Alfie Goodrich, and provides practical photography teaching in Tokyo. Weekly workshops, group and one-to-one lessons bring together photographers of all ages and abilities.

We also welcome submissions of photos and articles for this site, so please get in touch via our contact page. Thanks.

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