JARS v42n2 - The Color Rhododendron

The Color Rhododendron
Ed Bancroft
Bellevue, Washington

Reprinted from "Seattle Rhododendronland", Seattle Chapter newsletter.

Now that spring is here, it's time to get your photography equipment into the garden. Many rhododendron enthusiasts enjoy documenting their collections on slide film, and sharing their slides with others. Some members enjoy assembling slide shows for education, and to share their travels to other rhododendron areas. Hybridizers sometimes use photography as a recordkeeping system. Many members simply enjoy having slides just for themselves. No matter what your objectives are, it is likely that accurate color reproduction will be high on your list of technical priorities.
Rhododendron photographers experience several difficulties obtaining accurate color reproduction on slide film. Frequently, color shifts from blue to purple, or blue to pink, occur. Sometimes clear yellows, pinks and whites pick up blue tints. At other times, unusual and unexplained over exposures occur rendering the rhododendron colors on the slide film faded or washed out. On occasion, a loss of tone separation in reds and whites results in a loss of texture and definition in truss shots - we call this "blocking."
Some of these problems may be explained by the way in which the human eye sees rhododendron color. As humans, we see only visible light. However, in the wild, through successive generations of selection, rhododendrons have adjusted their colors to include colors most visible to bees, and in certain cases, birds. These colors may include the non-visible ultraviolet blue and infrared spectrums.
Like bees, films are sensitive to these colors. The invisible light is recorded and after the film is processed the slide projector reveals rhododendron colors that we did not see originally. Film manufacturers balance their films to best reproduce the "memory" colors. These include skin tones, blue sky and similar standards that everyone understands. Rhododendron colors and associated problems are low on the manufacturer's priority list. Looking for the magical film that will bail us out of these problems may not be very productive.
Members of the Seattle Chapter Photography Study Group are about equally divided between the use of Kodachrome (ASA 64) and Ektachrome (ASA 64 or 100). Generally, Kodachrome is warm in tone, very sharp, and has an excellent crisp contrast. Ektachrome is slightly cooler and has a pleasing color fidelity. Some say it is better for blues and whites. Slow speed Kodachrome (ASA 25) has outstanding color and is capable of distinguishing minute differences of tone within the same color. It also has excellent characteristics during long exposures when used in dim light, or in critical close-ups. Its big disadvantage is that it requires the sacrifice of 1 and F-stops as a result of its slow speed. Fast films (ASA 400) are a pleasure to use but you may encounter some sacrifice in color response.
Film selection is probably the least important consideration in obtaining good color reproduction. We are not certain yet about the role filters will eventually play in obtaining good rhododendron flower color. You will find the following factors far more important, and it is in these areas that you should concentrate your first efforts.
1.  Select cloudy calm days. On darker days, there is considerably less ultraviolet and infrared to influence your film. The lower contrast will promote better color saturation in your film exposure. Try to avoid the inclusion of a gray sky unless you can darken with a split image filter.
2.  Select early morning or late afternoon hours on sunny days. The midday overhead sun creates impossible contrasts. No matter what film you select, its latitude is not likely to permit you to expose properly for a subject partly in, and partly out of the sun. If on a visit or tour, you find yourself confronted with bright sun, it is usually best to expose for the highlights, and let the shady areas go dark. If your subject is in deep shade, you may need a warming filter to remove excess blue. If you have a choice, open shade is probably preferable, but try to avoid hot patches of sun in the background areas of your composition.
3.  Calculate your exposures carefully. Use care in how you meter your subject material. Don't be fooled by the background area. Hold your camera close to the most important part of your subject (flower, plant, etc.). Observe the highest light meter reading. After recomposing, shoot at or near an exposure value computed for that highest reading. This will be near the theoretical middle gray value. Chances are, you will record good saturated colors and the background will not be too bright. Next time add back stop if your whites turn out slightly gray. If your deep reds turn out a little too bright, reduce future exposures for deep reds by stop. Each color, if dominant in your composition, may require a certain amount of tuning.
An alternative method of determining exposure values is to take a meter reading off of a gray card held close to your camera. The gray card (Kodak Publication #R-27, $6.00) should be in the same light (quality and intensity) as your subject. Tilt the card slightly until you can determine an average light meter reading. Shoot at this light value. Since the gray card is middle gray (Zone V), your whites should record as whites and your blacks as blacks, and all of your other colors in their proper zones and densities. Use of a gray card is a means of measuring the intensity of your light source. Conventional metering measures the reflective quality of your subject.
Both methods are valuable. With some experience, you will learn which method is best in a given situation. Consistent determination of middle gray exposure values will give you a basis for fine-tuning your exposures to obtain the color results you need.
4.  Evaluate your results carefully. At first, start with short film rolls of 20 or 24 frames. The shorter rolls allow you to obtain results faster. If in doubt about your results ask experienced photographers for assistance.
Except in those rare once in a lifetime opportunities, try not to bracket your exposures. This is a very expensive habit, and you won't learn anything. You must make some mistakes in order to perfect your techniques. In the longer run learning to trust your own judgment will be an important step toward becoming an accomplished photographer.

Film selection is not particularly important for obtaining good rhododendron color reproduction. The quality of light and consistent exposure control are the most important factors. Filters will at times be useful, but buy them only after you have gained experience. Evaluation and interpretation of your results are important to solving technical difficulties. Avoid bad habits such as bracketing which impede your progress.