Cross-Polarized Crystal Photography
Part IV...Putting It All Together
Text and photography copyright Thomas Webster 2003. All rights reserved.
 
 
 
 
 
 
 
Vitamin C crystals evaporated from aqueous solution. Copyright Thomas L. Webster 2004

Putting it all together...Once I have the microscope set up and my crystals formed on microscope slides I'm ready to make my images. As I stated earlier in the section titled, "The microscope...", I cannot directly view the effects of the crossed-polarizing filters through the binocular head. The second polarizing filter, the "analyzer", sits over the trinocular tube in the bellows. However, I have become adept at predicting the effects of crossed-polarization when viewing singly polarized substances. Those areas of a microscope slide that will give "good color" will take on a 3-dimensional appearance compared to the surrounding crystals. These areas may also show a hint of coloring, too. When I observe areas, such as these, in the binocular head I will then switch to observing through the camera's viewfinder. More often than not I will be able to see the effects of the crossed-polarizing filters in all their glory.

Unless something looks particularly inviting I attempt to avoid high powers. I generally use a 2.5x or 3.3x projection eyepiece combined with a 4x flat-field achromatic objective lens for most of my photographs. I am looking to add a 2.5x plan achromatic objective lens for my crystal photography. The crystals that form aren't as small as one would expect them to be. Many crystal formations can be quite large, especially vitamin c that forms large, plate-like crystals. Occasionally I will go to higher powers when I see some interesting, fine detail but the images are dim and hard to focus. Two polarizing filters can really "soak up" a lot of light! I have a 30 watt illumination system that is normally fine for exposures at higher powers. However, 30 watts is barely adequate for powers over 100x. I am currently converting a 300 watt slide projector as an illumination system. Stay tuned for that article!

Focusing the image on the camera's film plane can be quite a challenge. I do have a special macrophotography and photomicrography focusing screen installed in my camera but, again, the observed image can be pretty dim and difficult to see. I also suffer from diabetes that can sometimes cause daily shifts in my visual acuity. The reticle in the right-angle viewfinder is focusable on a central crosshair to allow for differences in eyesight correction. Most of the time I find this woeflly inadequate and highly variable. Instead of relying entirely on focusing through the viewfinder I have devised a system that works pretty well. I have taken a blank microscope slide and have carefully frosted a central area with wet-and-dry aluminum oxide sandpaper. I lock open the shutter, open the camera back, and place the frosted central area of the microscope slide over the film plane with the frosted side down. I then use a focusing loupe to carefully focus the crystal image on the film plane. Afterwards, I adjust the reticle focuser on the right-angle finder such that I see a sharp overall image through the camera's viewfinder.

I make all of my exposures on either Kodak or Fuji ISO 100 color negative print films. First of all, I am a very "financially challenged" individual with a teenage daughter to raise! Color negative films are much more affordable than color transparency films. I can buy four, 24-exposure rolls of Fuji Super HQ ISO 100 color print film (my favorite) at WalMart for about $5.00. Processing only costs about $2.00 per roll. Second, since I scan all of my images it doesn't really matter if I am scanning color negatives or color transparencies. Third, color negative films have a higher dynamic range than color transparency films. The new consumer color negative emulsions are getting finer grained and more saturated every year. Just what we need for photomicrography! Depending on the magnification exposures will range anywhere from 1/8 second to 7 seconds. I use an 80B or 80C filter to compensate for the warm tungsten illumination system. Exposures with thin crystal preparations can be tricky. Because of the clarity of the crystal preparations and the fact that transmitted light is used I invariably have to use an EI of 200 to 260 to achieve properly exposed negatives. (End...)

 
 
Front Page Articles Forums & Galleries Links About Us
Website design and graphics copyrighted Reasonable Expectations Productions 2004. All rights reserved. All images are copyrighted by the original artists/photographers. No content, neither written nor graphic, may be reproduced without expressed written permission of the copyright holders. Copyrights are filed accordingly with the Library of Congress. Infractions of the copyright laws are actively and aggressively litigated and may subject the defendant to actual and punitive damages as well as reimbursement of court and attorney costs. No exceptions! Content on the Internet may be free for public viewing. However, content on the Internet is not free for public use. Let's all work together to protect copyrighted works displayed on the Internet. These sites are best viewed with Microsoft Internet Explorer® version 5.5 or later. Web layout and design produced with Macromedia Dreamweaver® 6.01. Image preparation's accomplished with Adobe Photoshop® 6.01. Interactive content produced with Macromedia Flash® 5.0.