It is one of the most remarkable things connected with the amazing subtlety of appreciation possessed by the human eye, that of the millions of heads in the world, and probably of all that have ever existed in the world, no two look exactly alike.  When one considers how alike they are, and how very restricted is the range of difference between them, is it not remarkable how quickly the eye recognises one person from another?  It is more remarkable still how one sometimes recognises a friend not seen for many years, and whose appearance has changed considerably in the meantime.  And this likeness that we recognise is not so much as is generally thought a matter of the individual features.  If one sees the eye alone, the remainder of the face being covered, it is almost impossible to recognise even a well-known friend, or tell whether the expression is that of laughing or crying.  And again, how difficult it is to recognise anybody when the eyes are masked and only the lower part of the face visible.

[Illustration:  Plate L.

FROM A DRAWING IN RED CHALK BY HOLBEIN IN THE BRITISH MUSEUM PRINT ROOM

Note how every bit of variety is sought for, the difference in the eyes and on either side of the mouth, etc.]

If you try and recall a well-known head it will not be the shape of the features that will be recollected so much as an impression, the result of all these combined, a sort of chord of which the features will be but the component elements.  It is the relation of the different parts to this chord, this impression of the personality of a head, that is the all-important thing in what is popularly called “catching the likeness.”  In drawing a portrait the mind must be centred on this, and all the individual parts drawn in relation to it.  The moment the eye gets interested solely in some individual part and forgets the consideration of its relationship to this whole impression, the likeness suffers.

Where there is so much that is similar in heads, it is obvious that what differences there are must be searched out and seized upon forcefully, if the individuality of the head is to be made telling.  The drawing of portraits should therefore be approached from the direction of these differences; that is to say, the things in general disposition and proportion in which your subject differs from a common type, should be first sought for, the things common to all heads being left to take care of themselves for a bit.  The reason for this is that the eye, when fresh, sees these differences much more readily than after it has been working for some time.  The tendency of a tired eye is to see less differentiation, and to hark back to a dull uniformity; so get in touch at once with the vital differences while your eye is fresh and your vision keen.