Prutchi - Exploring Ultraviolet Photography

FRONT COVER(small photos)Bidens and petunias photographed in their natural environment under sunlight. Taken with a modified Canon T1i and EL Nikkor 80 mm f/5.6 enlarger lens mounted on a M39 focusing helicoid. Filters: X-Nite CC1 (left); Baader U (center); Schott UG-5 and S8612 glass panes (right).

FRONT COVER(large photo)Perennial sunflower photographed with a modified Canon T1i with an Asahi Takumar 35mm f/4 lens and filter made by stacking Schott UG-5 and S8612 glass panes. This was illuminated by a Vivitar 285HV flash, converted to full-spectrum output.

Copyright 2017 by David Prutchi.

All rights reserved.

All photographs by the author unless otherwise noted.

Published by:

Amherst Media, Inc., PO Box 538, Buffalo, NY 14213

www.AmherstMedia.com

Publisher: Craig Alesse

Senior Editor/Production Manager: Michelle Perkins

Editors: Barbara A. Lynch-Johnt, Beth Alesse

Acquisitions Editor: Harvey Goldstein

Associate Publisher: Kate Neaverth

Editorial Assistance from: Carey A. Miller, Sally Jarzab, John S. Loder, Roy Bakos

Business Manager: Adam Richards

ISBN-13: 978-1-68203-126-1

Library of Congress Control Number: 2016941019

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Notice of Disclaimer: The information contained in this book is based on the authors experience and opinions. The author and publisher will not be held liable for the use or misuse of the information in this book.

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Table of Contents

Contents

A multispectral dusk quadriptych of Commerzbank Tower in downtown Frankfurt viewed from the Eiserner Steg (the Iron Footbridge) across the Main River. The panels at left, from top to bottom: show the visible light, infrared (Hoya R72 720 nm long-pass), and near-UV (Baader-U) images. The main panel is a multispectral composite with the combined visible channels assigned to red, IR to green, and UV to blue. The images were aligned with SIFT Flow algorithm. The photographs were taken with a modified Canon T1i camera and an Asahi Takumar 35mm f/4 lens.

The mouth is a carving on one of the corners of the Three-Windowed Temple in Machu Picchu, Peru. It held a wooden beam that supported the buildings roof. This photograph was taken with a modified Canon T1i camera and an Asahi Takumar 35mm f/4 lens with a Baader-U filter. It was white-balanced in Canon Digital Photo Professional against the wall rocks in the background. The saturation of the sky and mountains was increased in Photoshop Elements.

D avid Prutchi received his Ph.D. in engineering from Tel-Aviv University in 1994, and then conducted postdoctoral research at Washington University. His area of expertise is the development of active implantable medical devices and he is the Executive Vice President of Engineering at Impulse Dynamics. He is an adept do-it-yourselfer and avid photographer dedicated to bringing cutting-edge experimental physics and technical photography within the grasp of fellow buffs.

Dr. Prutchi has published over thirty papers and holds over seventy patents. He is the lead author of the book Design and Development of Medical Electronic Instrumentation: A Practical Perspective of the Design, Construction and Test of Medical Devices (John Wiley & Sons, 2004) and co-author of Exploring Quantum Physics through Hands-On Projects (John Wiley & Sons, 2012).

The real voyage of discovery consists not in seeking new landscapes, but in having new eyes.Marcel Proust

O n a sunny morning in February 1800, astronomer Sir William Herschel was testing various filters in preparation for observing sunspots when he noticed different amounts of heat passing through various colored filters, making him think that each color may itself have a characteristic temperature.

His discovery of infrared radiation showed that there are types of light that we cant see.

Curious about this idea, Herschel split a beam of sunlight through a glass prism and measured the temperature at the location of each color in the projected rainbow. His blackened-bulb thermometers showed an increase in temperature as he moved the thermometer from the violet, through the blue, green, yellow, orange, and into the red portion of the spectrum. Much to Herschels surprise, the temperature just beyond the red portion of the spectruma region where no light was apparently projected by the prismhad the highest temperature of all.

Further experimentation led Herschel to conclude that an invisible form of light must exist beyond the red portion of the color spectrum. Herschel named the radiation calorific rays. Although his hunch about temperature was not correct, his discovery of infrared radiation showed that there are types of light that we cant see.

A year later, in 1801, Johann Ritter, a science student at the University of Jenna, was experimenting with silver chloride, a chemical that turned black when exposed to sunlight. Ritter had heard that this chemical, which more than a decade later would be used to make the very first photograph, reacted more strongly when exposed to blue light than to red light. Like Herschel, Ritter used a glass prism to split a ray of sun, and then placed silver chloride under each color of the spectrum. Ritter noticed that the silver chloride showed little change in the red part of the spectrum but increasingly darkened toward the violet end of the spectrum. To his amazement, the strongest reaction happened well beyond the violet cutoff, where no visible light could be seen. Johann Ritter called the invisible radiation beyond violet chemical rays. Today, this portion of the electromagnetic spectrum is known as ultraviolet light.

Indeed, we now know that visible light is simply a type of electromagnetic wave, just like the enormously long waves that we use to transmit AC power, the radio wavelengths that are the foundation of our wireless society, and the extremely short wavelengths of gamma radiation. The only difference between visible light and the rest of the spectrum is that it is the range of electromagnetic waves that our eyes can see (; next page).