The high dynamic range images shown in this web document were created by a Kodak ProCD scanner using a "Reversal Kodak 4050 E6" setting, which treated the negatives as transparencies in order to capture their full dynamic range. However, since the result is still represented as 8-bits of integer data per primary, the dynamic resolution of the results is not very good, and quantization errors appear as noise or grain in the resulting image.
The colors in the images scanned in this way are also unreliable because we were working from three scans of a Macbeth ColorChecker chart and had to extrapolate the toe and shoulder of the response curves. Therefore, the sky in the images may appear to have an unnatural greenish cast which is not an accurate representation of the original scene. To avoid the distracting appearance of these color shifts, we provide below the same comparison images below in black and white.
Click on an image to see a larger version.
Figure 4. A photograph containing a large range of luminance values, shown here as it was recorded on a PhotoCD by standard procedures.
Figure 5. A standard PhotoCD scan shown darkened in (A) and brightened in (C). The same negative scanned and stored to preserve the original dynamic range, shown darkened in (B) and brightened in (D).
Figure 6. The same image, digitized using a high dynamic-range encoding, then later adjusted to fit within the dynamic range of a standard display.
Last Update: September 8, 1997.