Creating a Camera Curve Profile

When using PhotoImpact's High Dynamic Range (HDR) to optimize images, you first need to generate a camera response curve. A camera response curve indicates how the camera's light sensor reacts to light. A camera response curve is saved as a camera curve profile. Since the sensitivity to light of sensors in digital cameras vary, you have to save a camera curve profile for each digital camera you use.

NOTE: PhotoImpact includes preset camera curve profiles for some digital camera models. If there is a camera curve profile for your camera, use it when optimizing images.

Step One:

Open all the bracketed photos you want included in your HDR image. Ideally, five or more source images are required to produce a camera curve profile. For illustration purposes, this tutorial will only use three images. We will use the images in the PhotoImpact Samples folder. Go to the path: C:\Program Files\Ulead Systems\Ulead PhotoImpact 10\Samples\HDR. Open HDR 1-1.jpg, HDR 1-2.jpg, and HDR 1-3.jpg in PhotoImpact.

When you make a camera curve profile, use the bracketed pictures taken by your camera. To learn how to bracket or take multiple pictures with different exposure settings, refer to the Steps to bracketing tutorial.

Sample 1 has intense shadows.		Sample 2 shows more details than Sample 1.

In Sample 3, highlights are washed out.

The three sample pictures have good and bad points. The exposure settings in the first sample image shows perfectly exposed blue skies but it produced an intensely dark room interior. The exposure settings in the second picture maintains the relaxing colors of the mountain range but it washed out the colors of the sky. In the last image, the exposure settings used made the varnished wall interiors visible but it overexposed the ackground.

When you create your own camera curve profile, make sure that you use images with a wide exposure difference among the highlights, midtones and shadows, to obtain a better reading of the camera response curve.

Step Two:

Select Photo: High Dynamic Range.

Step Three:

In the HDR Composition tab, select Auto generate from the Camera curve profile drop-down menu.

Step Four:

If you are using Exchangeable Image Files (EXIF), the F-stop interval is automatically calculated since EXIF files record all the exposure settings used to take the picture. However, if you are using non-EXIF images, you need to manually specify the F-stop interval from 0.1 to 10. Generally, using an F-stop interval of 1 to 1.5
produces an optimal result.