Hand Drawn Holography

by Nils Abramson


I have with great interest studied the discussion about making holograms by scratching a surface and those explained by William Beaty were especially impressive. I would like to add information from some of my own publications. First I quote from my paper:

THE INVENTOR HANS WEIL AS A PIONEER OF HOLOGRAPHY

Nils Abramson, Holography-Jahrbuch 1989/90, p. 1.15, Rita Witting Publishing, Germany.

...Hans Weil is an artist who specializes in sculptures, and we are collaborating on the exploitation in art of the three-dimensional effect of holography. One of the results is a hologram constructed by Hans Bjelkhagen and displayed at an exhibition in Chicago...

...Hans Weil is also responsible for inventions in the field of optics, and it surprised me greatly to discover that he holds patents in branches of optics that I regard as representing a type of forrerunner to holography - a kind of incoherent holography. His UK Patent No. 37.208/34 of December 1934 "Improvement in Advertising and the like Signs", describes methods of producing "directive reflections by grooving a metal surface or transparent sheet of glass".......

..."Each set of information becomes visible only when the surface is illuminated from a particular direction." (In modern holography this is expressed by saying that the various hologram images must be reconstructed with light from different directions)....

....The patent also points out.... "different sets of information to be visible only from specific angles of observation, and that it is thus possible to produce stereoscopic images which have a three-dimensional effect without any need for the observer to be equipped with special glasses or the like"....

....It is even pointed out that the "grooves can be made extremely small, e.g. consist of the scratches caused by grazing with sandpaper or the like"....

....The patent further states:" The reflecting groups of surface elements may represent stereoscopic pictures or moving phases so that by simultaneous or successive stereoscopic or kinematographic effects respectively can be obtained."The latter method appears to be a direct forerunner of modern multiplex holograms,.....

...Swedish patent application No. 753/37, filed 23rd March 1937, concerns a "Device for Plastic Projection". Like the father of the hologram, Gabor, Hans Weil attempted here to further develop his method, to make it possible to project stereoscopic film with the help of a projection screen having "selective reflection". My impression on reading this one of Hans Weil's patent applications was that it was an exact copy of Gabor's - but written about 30 years earlier. There is, however, one significant difference: Gabor constructed his projection screen with the help of coherent light, while Hans Weil used primitive mechanical methods...

In my view Hans Weil's inventions represent a type of incoherent holography in which the actual exposure stage is missing, perhaps because Hans Weil did not have access to coherent light in 1933.

My friend Hans Weil is now 95 years old but still fit for fight.

I also want to refer to my book

(2) THE MAKING AND EVALUATION OF HOLOGRAMS
Academic Press, London 1981 and 1986

Page 169: The focusing effect from "motion trails".

Here I explain the shape and localization of holographic interference fringes by using an analogy to the shape and apparent localization in depth of patterns caused by reflections from scratches. I explain why and how we see patterns formed by grooves on a reflective or transparent surface. Fig. 5.8 and Fig. 5.9 show this effect:

" A steel disc has been turned in a lathe so that its flat surface is covered by circular grooves. These grooves work like an incoherent grating and reflect light as in the "motion trails" of Fig. 5.8. Thus the two methods produce identical patterns when illuminated and observed in identical configurations. The difference is that holographic interferometry produces a set of fringes while the analogy based on reflection from "motion trails" only mimics the zero-order fringe."

Finally I want to refer to my next book:

(3) LIGHT-IN-FLIGHT

or

THE HOLO-DIAGRAM:THE COLUMBI EGG OF OPTICS
to be published by SPIE in 1996.

Among other things, this book discusses how many different optical phenomena can be explained by diffraction from more or less ordered gratings.


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