If you want to merge two images in Adobe Photoshop, you can often achieve this without having to resort to isolation techniques! The trick is to firstly use Blend Modes to merge the Layers & then adjust the Layer Style to balance the difference in brightness between them.
STEP 1: With the two images you want to merge opened in Photoshop, place the foreground image on it’s own Layer above your Background Image. Select the top Layer, in my case, this is the bird in the illustration, and set the Blend Mode. There is no set formula for which Blend Mode to use, and you have several to choose from to get the best result. However, there is a general pattern to what works and when.
Multiply & Screen Blend Modes work best on images where you are trying to blend a dark object on a bright background. The bird here is on a light background, so in this case, Multiply works best. On the other hand, if the object you are trying to merge is on a very dark background, the Screen Blend Mode is generally the way to go.
You can see from the example image below, that the images have now merged because you can see the trees through the bird image. However, there is a block of color around the bird that is a darker blue than the rest of the sky. This is where Layers Styles come into play.
STEP 2: Working from the top Layer, double-click anywhere on the Layer towards the right-hand side; illustrated below as a yellow blob. This brings up the Layer Style panel.
STEP 3: Select Gray from the ‘Blend If’ pull-down menu. There are two sliders in the Layer Style Panel. One says: “This Layer”; which corresponds to the Layer you have selected. The other says: “Underlying Layer”; which, as its name suggests, is the Layer underneath the Layer you have selected. The sliders represent Black Tones on the left-hand side and White Tones on the right-hand side. In this example I needed to blend the highlight tones from the bird Layer with the highlight tones in the background; so I targeted the right-hand slider of “This Layer”.
The technique is to gradually move the Adjustment Pin until the point that the background portions around the blended object disappear. The settings I ended up with are illustrated below.
STEP 4: When you use this method, you can end up with a harsh transition line on your blended image. In this case, there isn’t one, but as a matter of course I refine the blend at the transitions by selecting ‘Option’ (on a Mac) or ‘Alt’ (on a PC) whilst clicking the Adjustment Pin. This splits the pin into two, as illustrated below, and allows for finer adjustment of the transition so that it blends in. When you are happy with the Adjustment select OK to close the Layer Style Panel.
Most often at this stage, you need to adjust the brightness of the blended object. In this example, you can see that the bird and the background is darker in the blended image compared to how the individual images started. This darkening is a consequence of the blend mode used on the Layer.
STEP 5: From the Layers Tab select ‘Create New Fill Or Adjustment Layer’ using the icon at the bottom of the panel, and then select ‘Brightness/Contrast’.
This creates a new Layer and opens the associated Properties Panel to adjust the Brightness & Contrast.
Using the sliders in the pop-up window, adjust the Brightness and Contrast as needed. However, you will notice that this adjusts our foreground and the background! Ignore this for a moment! Set the levels you desire for the foreground element.
STEP 6: Make sure you have the Mask selected on the Effect Layer. Now invert the mask using Command I (on a MAC) or Control I (on a PC). This hides the Brightness & Contrast effect.
STEP 7: Select a medium brush with a soft edge, and the flow set to about 40%. Make sure the color of the brush is set to white. With the mask selected still in the Layers Tab, use the brush to paint the foreground object where you want the brightness effect to be applied.
