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COLOUR GROUP (GB) DAVID ALAN PALMER July 1933 - June 2000.

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Presentation on theme: "COLOUR GROUP (GB) DAVID ALAN PALMER July 1933 - June 2000."— Presentation transcript:

1 COLOUR GROUP (GB) DAVID ALAN PALMER July 1933 - June 2000

2 COLOUR GROUP (GB) Christ’s College, Hendon Lane, Grammar School Imperial College - physics, 1952 - 1955 Imperial College - PhD, 1958: supervisor W.D. Wright National Physical Laboratory - 1958 National Physical Laboratory - W.S. Stiles

3 COLOUR GROUP (GB) NPL - general duties including photometry NPL - Brian Crawford & colour rendering NIC - chair of colour rendering committee 1965-7 IoO - Institute of Ophthalmology, 1967

4 COLOUR GROUP (GB) MESOPIC PHOTOMETRY

5 COLOUR GROUP (GB) MESOPIC PHOTOMETRY “The equivalent luminance L of any light may be expressed, to a good approximation, as a function of its scotopic and photopic luminances.” The question is, “What is this function?” David measured scotopic and photopic luminances by matching test lights of different wavelengths to white light of 2042K At match, L V, the equivalent luminance follows the relation: and the scotopic and photopic luminances can be calculated and log L P plotted against log L S

6 COLOUR GROUP (GB) David’s plot of log L P against log L S

7 COLOUR GROUP (GB) Palmer said that ideally the plots should show, “straight lines parallel to the P axis at very low levels, and parallel to the S axis at high levels.” But additivity was not perfect so there were departures from this especially at the ends of each curve. The data fitted adequately the expression: which is the form that the Palmer Mesopic Model is usuall set out: the figure shows how well the data fit the relation

8 COLOUR GROUP (GB) Data from other workers fitted the model well considering the problems know to exist with additivity - here are data from Kinney, JOSA, 58:1296, 1968

9 COLOUR GROUP (GB) Christmas Celebrations David was known for celebrating Christmas in style - a chosen theme, usually Dickensian, was followed for food, drink and decor and the lab had the benefit of last years decorations, for example, celebrations with Captain Cuttle from Dombey and Son In this David revealed high talent as an artistic draughtsman

10 COLOUR GROUP (GB) ENTOPTIC PHENOMENA - in art the light source was seldom depicted because glare, halos and contrast ratios are not easy or possible to capture convincingly

11 COLOUR GROUP (GB) A search for halos and glare showed many artists capturing the drama of light and shade but hiding the source

12 COLOUR GROUP (GB) COLOUR RENDERING... the effects of new fluorescent lamp phosphors on clinical evaluation of patients and skin lesions This was the first of a long series of papers on colour rendering and....

13 COLOUR GROUP (GB) COLOUR RENDERING And this was the last set of papers in the series

14 COLOUR GROUP (GB) COLOUR RENDERING For this work the team were awarded the Walsh-Western Bronze Medal of the Chartered Institute of Building Services Engineers in 1993

15 COLOUR GROUP (GB) There we had fun with sunglare protection (i.e. sunglesses) RETIREMENT In the ninties David retired and then worked afternoons at the University of Westminster We evaluated sunglasses for magazines and checked for safety a whole range of toys which contained laser light sources

16 COLOUR GROUP (GB) Traffic signal light recognition involved sorting out the infamous Q Factor and doing experiments on signal colour recognition

17 COLOUR GROUP (GB) CHRISTMAS again....and the sloe gin recipe competitions continued as did the search for the perfect microwave oven baked Christmas Pud David continued his work, started with Brian Crawford years before, on luminosity functions

18 COLOUR GROUP (GB) David showed normal observers’ photopic luminosity functions for large fields fell into one of three groups

19 COLOUR GROUP (GB) David measured protanopes’ scotopic luminosity functions and showed they were reduced at long wavelengths - evidence that scotpic vision is a mix of rod and L wavelength cone inputs

20 COLOUR GROUP (GB) David re-analysed the original scotopic luminosity function data of Crawford which had been used to formulate the CIE internationally agreed curve and found some surprises: many curves were considerably narrower than the CIE curve and the peak wavelengths were grouped as shown below

21 COLOUR GROUP (GB) David started to re-measure these curves with modern equipment but had to know about pre-retinal absorption so we set about measuring the macular pigment We made many prototypes with David’s favourite material - card & UHU glue Six instruments of the final design were made and are used across Europe It was whilst calibrating one of these that David was taken ill - he never worked again

22 COLOUR GROUP (GB) PROMOTION OF SCIENCE David hated the way the Government treated science and scientists, and was appalled at the general lack of understanding of science, especially by those “educated” elites that made up various authorities He worked to improve the understanding of science with, e.g. the Institute of Physics and the Royal Institution

23 COLOUR GROUP (GB) James Clerk Maxwell - a model and hero

24 COLOUR GROUP (GB) DAVID PALMER vision scientist 1933-2000


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