''Sensitivity'' is a useful and valuable word in art criticism. Anyone possessing that quality is assumed to be very in tune with reality, cultural attitudes and values, and to be extremely aware of the subtleties and nuances of such things as color, shape, movement, and line.
Unfortunately, the word also conjures up images of The Sensitive Artist, someone so highstrung and finely tuned that the falling of a leaf can send him or her into ecstasy or despair. We are fortunate that this perception of the artist isn't as common as it was a century ago, although occasionally we must still put up with such nonsense from individuals whose ''feelings'' and ''profundities'' far exceed their talents. It's amazing, in fact, that some of these ''artists'' exhibit professionally, and that two or three have actually established respectable reputations.
What generally characterizes these people, however, is not sensitivity, but its opposite: self-absorption. They are so full of themselves that nothing beyond their own needs and feelings strikes them as worthy of examination or of being turned into art.
They miss the crucial point that being sensitive means being alert to the qualities and realities of whatever lies outside their own narrow frames of reference, and that it means becoming as enlightened as possible about the nature, beauty, and significance of life itself.
Even genius, that potentially most arrogant and self-blinding of all human attributes, must become sensitive to its environment if it is to achieve greatness. Considering the grandeur of his talent, it is truly amazing how alert Rubens was to every nuance, texture, and detail of the world around him. And, given his overwhelming passions and anxieties, it is difficult to understand how Van Gogh could maintain his extraordinary clarity of vision when confronted by something so ''ordinary'' as cornfields and sunflowers. Even Picasso, the most iconoclastic and gung-ho of all recent geniuses, was always profoundly responsive to the appearances and deeper dimensions of reality.
Some form of sensitivity is needed on all levels and in every area of art, from the greatest masterpiece to the humblest study, from decisions affecting style and theme to those concerning medium and technique. Even Nolde's and Kline's most passionate canvases were conceived and executed with considerable respect for ideas, emotions, and materials.
Since sketches and drawings are so immediate and autographic, so responsive to every nuance of an artist's creative sensibility, they make excellent illustrations for any discussion of sensitivity in art. With that in mind, I've chosen a drawing by Kang Lok Chung, an artist who was born in Canton, China, in 1947 and who moved to Hong Kong in 1972 and then back to the United States in 1977. Beyond that, I know only that he draws beautifully and in a style that fuses Western ''realism'' and classical ideals with a subtly Eastern tonal and spatial sensibility.
My first reaction to the work illustrated here was surprise that anyone today would attempt something so difficult; my second, mild astonishment that anyone could accomplish the task with such sensitivity and formal tact. Every line, tone, detail, and compositional device is given its precisely appropriate emphasis and placement. As a result, the finished drawing does not end up as a piece of empty virtuosity, as it might have done in lesser hands.
Particularly effective (and difficult) is the manner in which the artist played the informal - even quite jumbled - intricacies of the tree, its branches , twigs, and shadows, against the severely formal facade and details of the building. The result is pictorial drama of a fairly sophisticated order, the sort of thing relatively few artists can manage successfully, let alone as exquisitely as in this work.
But there's more. Careful study will reveal that the drawing's surface has been carefully modulated to present a great variety of whites, grays, and blacks; that lines have been strengthened, lightened, or elongated to lead the eye more effectively from area to area or to fashion interesting patterns and designs; that the two windows have been treated very differently to reduce visual boredom; and that no detail has been permitted to draw attention to itself at the expense of the picture's ensemble effect.
Further study - a good method is to place one's finger over certain details to see how altered the drawing would be without them - will indicate how sensitively the artist went about his job. Imagine how heavy the right side would be had he made both windows equally dark, or how cluttered the entire image would seem had he articulated every detail on the left. Place a thumb over the smaller, more distant arches, and note how essential they are as a balancing device and as a formal ''echo'' to the two arches on the right. And finally, visualize how much less effective the tree would have been as solid gray and black. Without its occasional light branches and twigs - particularly those sweeping up toward its top, and those clustered at lower left center - the remarkable pictorial drama between tree and building, between the informal and the formal, would never have been achieved.