Digital Imaging: HDR

Raw files and High Dynamic Range images:

HDR: High Dynamic Range imaging is when several exposures of the same composition are combined to bring out all of the tones and contrasts, creating a greater dynamic range throughout an image. The first use of this technique was in the 1850's when French Photographer; Gustave Le Grey wanted to photograph seascapes, capturing detail in both the sea and the clouds in the sky. He achieved this by combining two negatives together, one of the detailed clouds in the sky and one longer exposure capturing the dark sea.  Below is an example of Le Grey's early HDR imaging:

Gustave Le Gray- Brig in the moonlight.

http://www.unframedworld.com/wp-content/uploads/2012/01/HDR-Photo-by-Gustave-Le-Gray-870x700.jpg

It goes without saying that the technology has developed immensely since the days of pioneers like Gustave Le Gray. When creating my HDR image for this blog entry I had numerous digital methods to choose from. As it was the most convenient method for me, I chose to create my HDR out of a single RAW file. A Raw file is quite often referred to as digital equivalent of a negative, this is because it contains unprocessed, uncompressed raw data from the sensor that is not ready for editing and printing until it is processed. This makes the image more versatile when it is initially opened in adobe photoshops RAW conversion control panel. 

Once I had taken a picture that I was happy with, I opened the Raw file in adobe photoshop. Because the file is not yet ready for editing it opens in a control panel. This panel allows me to make basic adjustments to the exposure, white balance, contrasts etc of my image before converting it into a file format more suitable for editing in photoshop, e.g: JPEG, TIFF. In order to create a HDR image I know that I must have several different exposures highlighting the dark right through the lightest tones of my image, therefore I adjusted the exposure of my file so like, le gray ,I have two separate versions of it. One of the files is under exposed, highlighting the lighter tones of the image e.g the clouds and sky. Another file is my original exposure bringing out all of the details in the building. Once I had my two separate exposures I opened them in photoshop.

I started by holding shift and dragging my underexposed image over on to the top of my initial image. holding shift ensures that the two images are perfectly aligned. I then added a layer mask onto my new underexposed layer. Using the gradient tool set at foreground to transparent I blended my two images together, bringing out the details in the building and keeping the dramatic sky above. 

Now I will use the Dodge and Burn tools to lighten and darken individual parts of the image until I am pleased with how it looks.  Here is my final image: 

I feel that sometimes HDR imaging can produce a cheap and tacky look, but by using this method I was able to exercise more control over the way the tones/colours came through. I feel that it can be a highly creative useful and fun technique when producing images.