Tony Thomas, firstname.lastname@example.org
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Tony Thomas asserts his moral rights to be identified as the author of this work, including text and images.
Also see the settup used by Cliff Ferris
Many otherwise good images of spread moths are spoilt by unsightly shadows (an admittedly personal bias) especially when 2 light sources are used and each lamp is at a 45 degree angle to the moth. 4 or more lights will usually eliminate most of the shadows. Mounting a spread moth on a glass sheet by inserting the pin into a small piece of modelling clay and then illuminating the glass from below will remove the shadows created by 2 lights above the moth. However, this method severely degrades the image; the moth looks as though it has become greasy. A simple method to eliminate shadows is to photograph the moth against a black background, but finding a non-reflective pure flat black background is not easy (black velvet is often recommended) and a black background is not always desirable.
I describe the method I use to get shadow-free images using 2 lamps. A listing of components, the rationale for choosing them and alternatives are given in an appendix.
2 Basic Needs + 1
The two basic needs are to have i) a large diffuse light source, and ii) the moth at a significant distance from the background so that the illumination can get behind the spread moth and eliminate any shadow. A third need is strictly personal. I like to work in a vertical position so that I can look directly through the camera eyepiece without bending my neck. This dictates that the light-box needs to be vertical rather than in the more usual horizontal plane. However, this latter need has been solved by a few manufacturers whose digital cameras have monitors or lenses that swivel.
i) Large Diffuse Light Source
I meet this requirement by the use of 2 daylight compact fluorescent bulbs, each with a built-in reflector and each of which gives a beam spread of 80 degrees (Fig. 1 ).
Fig.1. Some components for shadow-free lighting showing just 1 of the 2 lamps.
Each bulb is housed in a gooseneck lamp that is positioned at the edge of a white plastic funnel of top diameter 16 inch, bottom diam. 4 inch and depth 10 inch. The funnel is attached to a 1/4 inch plywood sheet that I clamp to a L-shaped board that supports the funnel such that the top opening is vertical (Fig.1). I have not yet got around to making a permanent supporting base!
ii) Moth-holder, Background Distance
The moth-holder is a 9 inch long disposable glass pipet (Fig. 2) with an internal diameter of about 1mm at its narrow tip.
Fig. 2. Moth-holder. This styrofoam block is for illustration only, the actual block is a 4-inch diameter disk of similar styrofoam.
A 4 inch diameter disk of 1 inch-thick closed-cell styrofoam with a very small centered hole is jammed into the inside base of the funnel. The tip of a 9 inch pipet is then passed through the disk from the outside base of the funnel so that the wide bottom half of the pipet sticks out of the funnel base (Fig.1). With this type of pipet, 4 inch of the tip projects inside the funnel. The disk acts as a support for the pipet and keeps the pipet in the center line of the funnel. An ice-cream container conveniently fits over the outside base of the funnel to protect the pipet from breakage.
With the foam disk and pipet in place at the base of the funnel a square piece of background paper, 5-7 inch on a side with a central hole for the pipet to pass through, is pushed down to touch the block. Because the paper is larger than the block it can be deformed into the shape of a shallow bowl with the bottom center touching the block and the edges curving up onto the funnel. Stick the 4 corners of the paper to the funnel with Scotch tape. Such a concave surface greatly reduces shadows. The paper is easily replaceable and thus a variety of colours can be used; darker for a light moth, lighter for a dark moth.
A spread moth is simply pinned into the glass tubing (Fig. 2). If the pin is extremely loose in the pipet (a #0 pin for example) or if the moth rotates to an unacceptable angle, carefully force some modelling clay (available from most toy stores) into the tip of the pipet BEFORE the pin is inserted.
I place the light-box described above on a table and use a digital camera on a table-top tripod equipped with a focusing rail (Fig. 3).
Fig. 3. Final set-up showing position of lamps and table-top tripod. Focusing rail rotated 90 degrees to show detail. In use, the focusing rail is rotated to point towards the moth.
The Arctiid image, Fig.4, is exactly how it was captured by a digital camera that had its white balance pre-set to the above system. Normally, I would completely fill the frame with an image this size but purposely left a lot of white space around the image to show the total absence of shadow. There IS a gradation of illumination from the top left corner to the bottom right - caused by my sloppiness in not accurately positioning the lamps - easily corrected in Photoshop.
Fig. 4. An actual image using the above set-up, completely un-retouched except that it has been compressed from its original 14MB .tif format to a 100K .jpg (with consequential loss of image quality). Note the total absence of shadow.