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Jan Hubička edited this page Jul 13, 2024 · 69 revisions

#Color-Screen Color-Screen is a collection of tools for working with scans of additive screen processes of early color photography.

Example
Flowers, Paget lantern slide 8x8cm, ca 1921 (left) and digital color reconstruction (right)

What is an additive color screen process?

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.

What we aim for?

Our tool offers (by now quite powerful) set of features for digitally restoring and enhancing early color photographs:

  • Accurate Color Restoration of negatives: Transform scans of negatives captured with additive color screen filters (which looks monochromatic and encode colors spartially) into vibrant color photographs with high degree of accuracy. By understanding individual color processes and original dyes used to produce the color filters, we can restore photographs into colors as they looked new.
  • Accurate color Restoration of transparencies: Most transparencies made using additive color processes faded or misregistered. These layered structures, containing a black and white slide and a color filter, can be digitally restored to original colors based on high-resolution scan ideally made including the infrared channel.
  • Enhanced Display and Printing: Ensure your early color photographs are ready for digital screens and physical prints. Traditional scans of these photographs often suffer from accentuated color screen patterns and color shifts. We use specialized demosaicing algorithms that recognize the specific color screen used. This allows us to create smoother digital files that preserve the image's fine details without introducing unwanted artifacts.
  • Stitching of scans made in multiple tiles: By understanding the geometry of color screen used to take the image, we can stitch individual tiles of scan with greater precision then it is achievable by general purpose panorama stitching tools. This precision is, in fact, necessary since the fine pattern almost never stitch without specialised care.

A Call to Collaboration

Early color photography is a fascinating and often under-appreciated field.

Collections of photographs captured using these early processes are rare and tend to be small. While individual collections might not warrant extensive digitization efforts on their own, together they represent a vast and irreplaceable historical record.

We are eager to connect with other researchers in this area to collaborate on digitizing, restoring, and sharing these collections. We believe our tools, developed over two years of active research, can be instrumental in bringing these forgotten photographs back to light.

If you have a collection of early color photographs, or know of researchers or photographers working in this field, or are interested in anything related to this area we'd love to hear from you. Our goal is to build a comprehensive set of tools that will make these unique pieces of history accessible to everyone. Please do not hesitate to write to Jan Hubička [email protected].

News

  • 2024, July 14: Color-Screen 1.0 released
  • 2024, July 8: Our talk proposal "Understanding colors of Dufaycolor" was accepted for 3rd Colour Photography and Film. See you in Amsterdam!

Software packages

Table of contents

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