Magic Of Duotones
When some people think of Duotones, they think something along the lines of the image above. The subject is split between one color and another. Yes, there many cases of images which may be colored in one or more tones of color. The technique is fairly simple as shown in this YouTube Video and the results can be very creative if colors are chosen well.
There is MUCH more to Duotones, Tritones, and even Quad tones which is included in the current release of photoshop. There are dozens of possible combinations and it is possible to change the background of a subject without the use of masks, cut-outs, or any other extraction mode. This is one of my longer posts, so please bear with me.
I photographed my subject against a grey background, and then loaded the image into photoshop. Like most things in photoshop, there are many ways to proceed, but I will try to describe a technique that is very flexible. First steps include:
A dialog box will open will a dozens of presets that you can choose from. Consider the many emails that you may receive on a daily basis for photoshop actions and Lightroom presets. Some of these offers can get expensive, and yet you have a large library of possibilities.
You could continue to Tritones, or even quad tones, but for this post lets keep it simple. Choose one of the presets and your image will change color corresponding to the preset that you have chosen.
Now, save your project (file-save), then return to your original document.
Your New image now rests above your original picture. You can adjust opacity of the newly created image if you wish if it appears too intense. The next step is to blend the two images together. You can scroll through the blend modes, however in my case I wanted to go with soft light blend mode.
So you can see, I how have a blue toned background with almost the skin tone of my original subject intact. In some cases however one additional step may be necessary when the blue tone overlaps onto the subject. There seems to be a little bleed over, especially in the subjects hand.
To normalize the skin tone back to the original, Choose layer styles (Fx button at the bottom of the adjustment panel) to bring up blending options.
Sliding the "Underlaying layer" slider to the right will bring back some of the natural tone to the skin from the subject.
A video description of this This process can be found with step by step instructions relating to background material and some additional editing tips. Although the speaker does not deal directly with changing the background, clearly it can be done with a little experimentation when it comes to blending modes.