This tutorial assumes a basic understanding of Photoshop (how to use layers and masks) and how to take photographs with different length exposures.

HDR stands for ‘High Dynamic Range’. In basic terms this means taking the best exposed elements from a scene using various length exposure shots from your camera and combining them during post-processing. Your eye can cope with extremes of exposure that a camera sensor cannot, so a single photograph will often contain areas of bright light or dark shadow that show no detail. This process allows us to see those details.

For example, taking a photograph of a window from inside a building will either:-

1. Show what is inside clearly but over-expose the exterior leaving a white square where the window is or…

2. It will show the exterior clearly and the details of the room will be a black silhouette.

If we take two different exposures of the same scene, one long and one short we can gather all of the information we need:

This longer exposure show us the details on the window sill but the sky is just a white glare.

Whereas the shorter exposure gives us the view outside but leaves everything inside black.

If we place the two images over each other in Photoshop (using auto-align if necessary) and then create a mask of the second, using a black brush we can mask the unwanted areas as follows:

This mask can be created with selecting areas and filling or with a more detailed brush (with white showing everything and black showing nothing). As you become used to the process the masking can become more complicated and varied, showing different degrees of each picture using different tones of grey on the mask.

The final image can then be touched up with various adjustments or filters until the required look is achieved. In this case I combined the two layers into another single layer. I then opened it in the Topaz Adjust plugin, slightly over saturated the colour and enhanced the detail and then placed it over the original layers and took the opacity down until I liked the final levels.

This shows the layers visible before saving.

The final result was this:

Of course a lot more detail would be visible if I washed the windows more often…

HDR images can be achieved in many ways. Simple masking and editing of two images or the combination of multiple images using software such as Photomatix or Photoshop. There are some very excellent tutorials for these to be found at farbspiel and stuckincustoms.