Wednesday, May 25, 2011

Greater detail makes HDR look good

HDR images are very pleasing, but have an unnatural look. Many of them remind me of the color rendering in Francis Ford Coppola's One from the Heart, filmed in the American Zoetrope studio, which produced also some of Wim Wender's movies with similar color rendering. The unnatural look comes from the dynamic range compression that is necessary to reproduce the images on media, I suspect mainly because the compression is only in luminance and not in chroma.

Regardless of the look, HDR images are very pleasing, and John McCann recently wrote the SPIE Newsroom article Human spatial processing accounts for dynamic range and color, in which he concludes:

At first, HDR imaging may have seemed best suited for improved recordings of scene radiances. However, glare limits the range of light that can be detected by cameras or the retina. All scene regions below middle gray are influenced, more or less, by the glare from the bright scene segments. Instead of accurate radiance reproduction, HDR imaging works well because it preserves the details in the scene's shadows. Spatial image processing preserves this information, but distorts accurate reproduction. Similarly, color constancy is the result of color comparisons of the entire scene.

Tuesday, May 24, 2011

James Bowmaker

On 4th May 2011 the Honorary Membership of The Colour Group (Great Britain) was bestowed on Professor James Bowmaker by the Chairman Andrew Stockman.

Jim Bowmaker is one of the leading and most-respected figures in colour vision research. His career has spanned more than 40 years since his first of more than 100 impressive peer-reviewed publications appeared in 1970. After a Postdoctoral Fellowship at UCLA, Jim moved to the MRC Vision Unit at the University of Sussex, then to Queen Mary College, University of London, and finally to the UCL Institute of Ophthalmology.

Jim is a scientist of international renown. He was awarded the Rank Prize for optoelectronics (vision) in 1988 with Jeremy Nathans, John Mollon and Gerry Jacobs, and was the Colour Group Palmer lecturer in 2005.

Jim's key scientific achievements include:

  • The precise determination, by microspectrophotometry, of the absorbance spectra of human and Old World monkey cone visual pigments and the hypothesis that there is spectral variability in the human L and M cones.
  • The establishment of the polymorphic basis of colour vision in New World monkeys, with the hypothesis that there is a single polymorphic locus on the X chromosome for L and M cone pigments in these species.
  • The identification of four spectral classes of cone, including ultraviolet-sensitive cones, in birds and fish, and establishing the potential for tetrachromatic colour vision in these species.
  • The identification of specific tuning sites within rod opsins and UV/VS cone opsins in fish, birds and mammals.
  • The establishment that at least seven spectrally distinct cone opsins can be expressed within individual species from the rapidly evolving cichlid fish of the African Great Lakes. These species determine their spectral sensitivity by differential expression of only three of the seven cone opsin genes.

James Bowmaker

Jim in the wild outside the laboratory, usually near a glass of red wine, eating good food, and with his wife, friends and colleagues…

[Source: The Colour Group Newsletter 2011-05 / Andrew Stockman]

Tuesday, May 17, 2011

Advising on color palettes

In the last couple of months I had been writing about the problem of selecting color palettes that are visually pleasing. I started with Mik Lamming's effort in bringing back to the office the colors that were sacrificed with the transition from mimeographs to Xerox copiers and from color-ribbon typewriters to IBM Selectrics. After a digression on the appearance of flamingos, I continued with the problem of selecting colors for VLSI design and illustration, showing the Meta-Palette and a set of other color selection tools.

Today I will step back a little and present a broader view. The problem of designing pleasing or harmonious palettes is as old as visual communication. In western culture a quantum leap occurred with Leonardo da Vinci's prolific work on color analysis and structure (leading to chiaroscuro), which continued with Michel Eugène Chevreul's simultaneous contrast (leading to Impressionism), and with Georges Vantongerloo's attempt to mathematically represent color palettes (leading to De Stijl and Bauhaus).

Essentially the Proto-Palette was just an evolution of this thread, made by a guy sitting in his office and talking to media designers. The fire test came around 1989, when it was decided that GlobalView's desktop would be in color. It turned out that the Proto-Palette tool (color harmony) was too regimented and the Digital Palette tool (palette database and color blending) needed a flexible user interface, so I integrated these tools, along with the earlier Meta-Palette and Maureen Stone's Color Tool.

This integrated set of tools allowed designers to start with a palette—for example, complexion—and add a contrasting color or changing a color lexically by adding a modifier like "muted." Codeveloping the color selection tools with the GlobalView GUI, all while the designers where working on the desktop (icons, etc.) proved to be very fruitful and efficient, leading to a paper at SPSE's 43rd Annual Conference (now IS&T). Since I had a full implementation, I gave a demo at the end of my presentation:

These tools were not the only game in town. At Tektronix, Jerry Murch and Joann Taylor were doing similar work. In Japan, Shigenobu Kobayashi had developed a system based on his Color Image Scale:

Color Image Scale, Shigenobu Kobayashi

All this came together around 1993 with the release of Canon's Color Advisor, described in L. Lavendel and T. Kohler: The Story of a Color Advisor. In S. Sü̈sstrunk and A. Lakatos, editors, Sixth Color Imaging Conference: Color Science, Systems and Applications, volume 6, pages 228–229, Scottsdale (Arizona), November 1998.

Canon Color Advisor screen dump

As they describe in their paper, Larry Lavendel and Tim Kohler actually surveyed their potential users, instead of just working with a few designers like I did. This allowed them to take into account the semantic aspects and thus create a tool that is easy to use by anybody, as opposed to my tools, which were usable only by designers and researchers.

It is a pity, the Canon Color Advisor did not survive in the market, because nothing better was produced after it and it looks like with their Canon Color Agent, Larry and Tim were up to something even much more powerful.

In retrospect, Canon's Color Advisor was just too far ahead of time. When in 1991 Canon implemented their device independent color management system, they tried hard to fully integrate it into Windows. When Microsoft refused to cooperate, Canon's CEO Dr. Yamaji flew to Seattle to negotiate directly with Bill Gates.

Unfortunately the latter declared that Windows users will never create color documents, and all that was needed in Windows was a fixed palette of 16 colors for the GUI, with none required for documents. When Dr. Yamaji insisted, Gates declared that color would require an additional floppy disk in the upcoming release of Windows 3.1, and at 15 million copies to be sold, the cost for enabling managed color documents would be the astronomical sum of $15 millions.

Unfortunately this forced Canon to bury its Color Advisor in the printer driver for a post-processing step, instead of making it available during document creation. However, it did save Microsoft $15 millions, and I am sure they made good use of it.

All this is old history. The notion of artists, designers, and scientists designing color palette selection tools is a concept of the second millennium. In this millennium, the process consists in crowd-sourcing large data corpora and using analytics to make inferences. The questions then are:

  1. Is crowd-sourced data reliable?
  2. Do the methods scale?
  3. When do we get a modern color advisor?

Wednesday, May 4, 2011

Color Selection

Play with the Milky Way

When you hear the words "Milky Way" in the context of astronomy, more than likely you envisage a galactic disk. But how do you know it's a disk? You certainly can't see any disk. If you go beyond the city limits to reduce the ambient light pollution, at best you will only see a dense band of stars, not a disk.

The notion of a galactic disk was inferred from this plot:

made painstakingly by the German-English musician and amateur astronomer, William Herschel in 1785. The modern rendition looks like this:

This one was also made by an amateur, an amateur photographer named Nick Risinger, and it's composed of 37,000 separate photographs. Not only that, but there's an interactive version. Wiredscience has the full story.

Tuesday, May 3, 2011

Red Lips

Yoko's Lips

Sometimes the news are old news. For example, in today's late night World News broadcast, NHK had a piece on a new lipstick technology presented last September at the International Federation of Societies of Cosmetic Chemists congress in Buenos Aires by Tomoko Ikeda of the Shiseido Research Center.

Current lipstick consists of a pigment suspended in a polymer. As the polymer dries out, the pigment easily transfers to other surfaces, like for example a mug. According to the news piece, Tomoko Ikeda mixed in the suspension a second polymer locking in place the pigments.

In patent-speak: Disclosed is a lip cosmetic which has a good gloss and a high stability while continuously being free from secondary stickiness after application. Specifically disclosed is a lip cosmetic characterized by comprising: (a) 4.5 to 35 mass% of glycerol monoisostearate; (b) 20 to 80 mass% of one or more kinds of methyl phenyl silicones which are not separated out when mixed with the component (a) at 90ºC but separated out when mixed with the component (a) at 25ºC; (c) 5 mass% or more, relative to the component (a), of water and/or 24 mass% or less, relative to the total cosmetic, of glycerol; and (d) 4 to 10 mass% of a wax.