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Color Screen is a collection of tools for working with scans of additive screen processes of early color photography.
Flowers, Paget lantern slide 8x8cm, ca 1921 (left) and digital color reconstruction (right)
Additive color screen processes used panchromatic negative which was exposed through a color screen filter pretty much same was as today CCD and CMOS chips use Bayer filter. The negative was then copied to (black and white) transparency which yield to color picture when viewed through the viewing screen filter.
Our tool can
- turn scans of negatives taken using additive color screen filters to color photographs with a high degree of accuracy.
- recover original colors of transparencies which faded or got misregistered. These transparencies sandwich black and white slide with a color screen. If digitized in infrared spectra one can obtain a scan of the slide (screens are transparent) and then re-add the screen digitally.
- additive color screen processes are hard to view on screen or reproduce. It is a common practice to digitize them in low resolution or somewhat out of focus to reduce unwanted artifacts caused by the color screen filter. We implement special demosaicing algorithms which understand the specific color screen used and produce smoother digital file without losing fine details of the image.
- TODO: What needs to be done before release
- Supported Processes: List of supported processes
- Collections: Known collections of additive color screen processes around the world
- ColorScreenGUI: Java based GUI
- colorscreen: Library, command line utility and a legacy GTK2 based GUI