How should field guides be illustrated?

A hundred years ago, there was little choice: colour plates had to be prepared by lithography, and were hugely expensive. So most of the work had to be done by text, supported by black-and-white line drawings, monochrome photographs, and with luck a few fuzzily-reproduced colour plates. Frankly, the line drawings were often the best bet.

Today, colour is far more affordable, and everybody expects it. In the main, line drawings are despised, though most of the field guides on my shelf still contain some, even if only in the Introduction and Glossary - somehow, explanation seems to be far easier with line drawings than with photographs.

Here, at the same scale and roughly the same size as printed (the printed photographs are approx. 46mm high) are the illustrations of the Comma butterfly, Polygonia c-album, from two of Michael Chinery's (excellent but very different) field guides to insects, together with some of the publisher's claims. Chinery has studied insects for a remarkable 60 years, and his books have changed with technology and inevitably publishing fashion. 

Firstly, I'd say that both books illustrate the Comma well. Both the painting and the photos show both the upper and under sides, which by the way neither book does for the majority of insects. Both types of illustration show the insect's shape as pinned in the museum; the right-hand photograph shows the more usual feeding posture on a flower, so here the newer guide has the upper hand.

The Comma butterfly is quite a tricky identification puzzle for beginners because it has a rapid dancing flight, looks very dark in bright sunlight, and is not always easy to approach. It is also smaller than common butterflies like the Peacock, so its pattern may be hard to see. The "jizz" which enables experts to identify it at once is difficult to capture in a book; what the beginner sees may not look much like the neat paintings or crisp macro photographs. Even the ragged wing edges may be hard to detect in flight, and the diagnostic white "comma" on the underwing is only likely to be noticed at close range.

A major difference between the illustrations is in the background. The painting has a neutral background, as do most of the insects in the book, whereas all the photographs have a natural background of flowers, leaves, twigs, bark, or in the case of the mosquitoes human skin. In many cases this provides valuable context. But to my eye at least, the flowery background to the left-hand Comma photograph is actually quite distracting; and even the pleasantly out-of-focus "bokeh" background to the feeding butterfly on the right is not as "in the background" as it could be.

As one more example, here are painting and photograph of an Ichneumon Fly, or at least its larvae - the painting shows the adult as well, which the later book does not.

Here, to my eye, the photograph is fascinating for the context that it reveals - a Large White butterfly caterpillar on a cabbage leaf. But the pair of small paintings are actually very clear and informative, making very good use of the limited space available in a field guide, even if the museum position of the adult insect is less helpful than it might be for field use. In short, I'm far from convinced that painting is obsolete in field guides. The new Collins Bird Guide is entirely illustrated with paintings, so it seems that birders and at least some publishers agree with this view. To see why this is so, let us compare the paintings in that guide to an older guide that attempted to use photographs.

 Well of course this comparison is unfair - the Bird Guide gives far more space to each bird, shows different plumages, uses text labels, and is prepared to an altogether higher standard for a far more discriminating audience than the presumably "total beginner" brief for the Photoguide. But even at the greatly reduced resolution of the paintings shown here, it is at once obvious that photographs, however attractive, are almost entirely useless for serious bird identification.

Publishers, clearly, are under pressure to make guides more approachable, more appealing to a general audience - in a word, more photographic; but, fortunately, also to make guides effective for identification - which means carefully-labelled paintings and drawings.

Finally, here is an illustration composed of both painting and drawings. There is no equivalent photograph because there couldn't be one in the space available in a field guide (and in a large monograph, nobody would attempt to use photos other than to give a general impression). The painting gives an accurate impression of the plant's jizz or "habit"; the drawings teach the beginner what to look for (and the names of the plant parts), and sharply distinguish the different species.

The paintings and drawings together are informative, precise to the point of being authoritative, clear, helpful for both novice and expert, and at the same time beautiful. It doesn't get better than this.

So perhaps field guides will return to where they began, with a helpful combination of detailed text, line drawings, paintings, and photographs. These can now be combined elegantly, whether on high-quality half-glossy paper (as in the new Collins guides), or in hypertext - assuming that a light, strong, cheap, low-power device bright enough to read in hot sunlight will one day arrive. Perhaps, at last, we will see an intelligent, practical, portable balance of all the available media to illustrate, explain, educate, and crucially to make field identification accurate, enjoyable, fast, and reliable.