Kodak Royal Gold RA100 scanned at 8000 spi |
Kodak Kodachrome KR64 scanned at 8000 spi |
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RA100 downsampled to 4000 ppi |
KR64 downsampled to 4000 ppi |
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RA100 downsampled to 2000 ppi |
KR64 downsampled to 2000 ppi |
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Color Negative Vs. Color Transparency
Color negative film and its grain structure require a high resolution scan to duplicate a natural result. Color transparency film is much less dependent on scanning resolution for smooth enlargement. At certain scanning magnifications, negative films (especially color) exhibit a phenomenon similar in appearance to increased grain. This is due to the aliasing between the randomized organic film grain and the structured grid of pixels. The effect is comparable to a Moiré pattern. For negative film, a sampling rate of 8000 per inch is highly recommended. This resolution will accurately describe the grains/dye clouds, thus avoiding aliasing. The alternate color negative Section A from the same negative shows less of the effect in the darker tones and how grain aliasing can vary within a single scan due to different grain sizes in different densities.
Section B
• The top row contains sections of the original 8000 spi scans. Underneath are downsamples directly from the 8000 spi scan.
• All sections are unsharpened and unfiltered.
• All sections are displayed at actual pixel size.