Kirby Fong, California

gray card, dafodil photographs

March 18, 2009
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Category: General

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Loyce,
The gray card has two distinct uses. The primary one is to get the exposure right (or close to right) when a scene is abnormal, i.e., does not reflect about 18% of the light that falls on it because it is very light or very dark. A daffodil filling most of the frame against a moderately dark background is close enough to 18% that autoexposure will generally work. The other use is to put a neutral (equal amount of red, green, and blue) object in the scene so that you can correct the color balance when editing the image. The reason not to use a piece of white paper is that you don’t know if it’s neutral. You have only to compare letter paper sold as 92 brightness, 98 brightness, etc. to see that there are various degrees of whiteness. The whitest whites have a little bit extra blue in them. Not all grays are neutral. The gray cards designed for photographic work are neutral. Our brains compensate for color casts by seeing as white anything that we know should be white. We also know enough about white, yellow, pink, red, and orange daffodils that we can figure out what they really looked like when the color or exposure of an image is a little off. We don’t have enough experience with green daffodils to tell from a picture what the real life color must have been. That’s why we want to get fairly accurate pictures of them for Daffseek. After that, people need to display the pictures correctly and have their monitors properly adjusted in order to see the picture as it was meant to be seen. By the way, there is a very common inaccurate green that bothers no one — stems. Often the stem is underexposed because it is farther from a flash than the flower. Between the fact that we all know what color stems ought to be and the fact that we’re looking at the flower, not the stem, it doesn’t bother us.
As for what makes a good photograph, there is no short answer. The more subjective aspects have to do with design and composition. Elements of design include line, shape, form, pattern, texture, and color. Composition includes what is included or excluded from the image, the aspect ratio, and relative position of the subject in the image. One of the most common guidelines for composition is the rule of thirds. This says it is generally more pleasing for the subject to be placed 1/3 or 2/3 of the across horizontally of 1/3 or 2/3 of the way up vertically. These all have to do with aesthetics and how or whether the image makes a statement.
Somewhat less subjective criteria for a good photograph are the technical ones of exposure, lighting, focus, depth of field, color accuracy, etc. These can still be somewhat subjective. You might want to use a warming filter or a soft focus lens to achieve a particular mood or effect. In the case of Daffseek, we want documentary images, i.e., images that are realistic that can help in identifying cultivars. Sometimes a view from multiple angles is needed, not just a single picture. The main light must come from an angle that give a natural but soft shadow and shows the texture of the perianth. Sometimes (usually with miniatures) you need to include a ruler to show the size of the flower.
So the short but unhelpful answer to what makes a good daffodil photograph is that it fulfills the purpose for which the daffodil was photographed — reference, artistic, or something else.
Kirby Fong

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