Here is another Layer mode that can provide a great 'quick fix' for a common image problem; under exposed or 'dense' images with a dark foreground or little shadow detail. Ideally this type of image should have been taken with 'fill in' flash. In some image applications a quick fix would be to use the gamma control, but this technique is useful if your image manipulation program doesn't have a gamma correction control dialogue.
So we'll use the 'Screen' mode to enhance an image taken in an interior with heavy backlighting.
This picture of a group picture was taken inside on a bright day without fill in flash. that means that the foreground is underlit and the outside through the windows is overexposed.
We can fix that fairly quickly in a similar fashion to the 'multiply' fix that we used in the previous task.
First open the image. It's 'interior.jpg' in the digisamples folder.
Step 2 - Duplicate the image layer 
Duplicate the background layer as you did in the previous 'multiplying' task, using the fourth icon from the right at the bottom of the Layers palette (arrowed).
Again, with the duplicate layer selected, as before Use the 'Blending Mode' drop down list to select 'Screen'.
Tip: Adjusting the 'Opacity' setting with this effect doesn't really work. Leave it on maximum - 255. To increase the Screen effect, merely duplicate the 'screened' layer - see below.
One of the drawbacks with this technique is that the view through the windows gets lighter the more you apply it. To change that you are going to have to start using selections!
Use one of the paths tools (indicated by the squares on the left). Use the tool to select the central window area - as indicated by the 'dotted' line in the screen grab. Imagine you are doing a 'dot to dot' drawing. On the topmost layer, just click to place a dot, then move along the 'edge' you want to outline, clicking as you go When you complete the selection - double click to 'join' it.
To use the selection, choose the menu option SELECT > From Path (or SHIFT + V). This will complete the selection (now shown by a moving dotted line.
You should also see a 'mask' shape in the layers palette (see the screen shot on the left) that indicates the area you are going to cut.
Finally, use the menu option EDIT > CUT. This will cut a 'window' of pixels out of your topmost layer, revealing the full strength of the pixels below.
To improve this effect on multiple screened layers, just keep applying the selection and cutting layers of pixels.