How to Increase the Range in a Digital Image

Using a tripod will allow you to take your images from the same position.

By creating high-dynamic range, or HDR, images, you can increase the range in your digital image, resulting in a much greater level of detail. By using software such as Photoshop, you can layer a series of images with varying exposures to create one complete image. The tonal mapping capability will lighten and darken regions of the image, allowing changes to the tonal curve to better suit the image. By following a few simple steps, you can create an HDR image with a greater tonal range than a standard digital photograph.

Things You'll Need

• Tripod

Instructions

1. Buy a tripod if you do not already own one. To create an HDR image, you will need to take a series of images from exactly the same position; a tripod makes this possible.

2. Take the photograph, using a minimum of three different exposures, however, five or more images will allow you to produce a digital image with a higher range. Start by taking an image two stops overexposed. Your next image should be one stop overexposed. The third image should have the correct exposure, and then your fourth and fifth images will be one and two stops underexposed, respectively.

3. Double-click on the Adobe Photoshop desktop icon or another program that allows you to perform tonal mapping such as Photomatix or Photosphere.

4. Click "File" then "Automate" and select the option to "Merge to HDR." Load your photographs into the exposure sequence, then click "OK."

5. Adjust the white point in the next window by moving the slider to highlight all the detail in the image. Once you are happy with the adjustment, click "OK" to create a 32-bit HDR image.

6. Convert the image to 16-bit. Click "Image" then "Mode" and select "16-Bits/Channel." Choose "Local Adaptation" from the list of tonal mapping options as this mode lightens or darkens regions of your image on a pixel-by-pixel basis, resulting in a higher contrast image.

7. Click "File" then "Save" to save your HDR image.

References

• Cambridge in Colour: High Dynamic Range Photography
• Luminous Landscape: Understanding Digital Blending