In order to put into practice this perspective of the variation and loss or diminution of the essential character of colours, observe at every hundred braccia some objects standing in the landscape, such as trees, houses, men and particular places.  Then in front of the first tree have a very steady plate of glass and keep your eye very steady, and then, on this plate of glass, draw a tree, tracing it over the form of that tree.  Then move it on one side so far as that the real tree is close by the side of the tree you have drawn; then colour your drawing in such a way as that in colour and form the two may be alike, and that both, if you close one eye, seem to be painted on the glass and at the same distance.  Then, by the same method, represent a second tree, and a third, with a distance of a hundred braccia between each.  And these will serve as a standard and guide whenever you work on your own pictures, wherever they may apply, and will enable you to give due distance in those works. [14] But I have found that as a rule the second is 4/5 of the first when it is 20 braccia beyond it.

[Footnote:  This chapter is one of those copied in the Manuscript of the Vatican library Urbinas 1270, and the original text is rendered here with no other alterations, but in the orthography.  H. LUDWIG, in his edition of this copy translates lines 14 and 15 thus:  “Ich finde aber als Regel, dass der zweite um vier Funftel des ersten abnimmt, wenn er namlich zwanzig Ellen vom ersten entfernt ist (?)".  He adds in his commentary:  “Das Ende der Nummer ist wohl jedenfalls verstummelt”.  However the translation given above shows that it admits of a different rendering.]

The rules of aerial perspective (295—­297).

295.

OF AERIAL PERSPECTIVE.

There is another kind of perspective which I call Aerial Perspective, because by the atmosphere we are able to distinguish the variations in distance of different buildings, which appear placed on a single line; as, for instance, when we see several buildings beyond a wall, all of which, as they appear above the top of the wall, look of the same size, while you wish to represent them in a picture as more remote one than another and to give the effect of a somewhat dense atmosphere.  You know that in an atmosphere of equal density the remotest objects seen through it, as mountains, in consequence of the great quantity of atmosphere between your eye and them—­appear blue and almost of the same hue as the atmosphere itself [Footnote 10:  quado il sole e per leuante (when the sun is in the East).  Apparently the author refers here to morning light in general.  H. LUDWIG however translates this passage from the Vatican copy “wenn namlich die Sonne (dahinter) im Osten steht".] when the sun is in the East [Footnote 11:  See Footnote 10].  Hence you must make the nearest building above the wall of its real colour, but the more distant ones make less defined and bluer.  Those you wish should look farthest away you must make proportionately bluer; thus, if one is to be five times as distant, make it five times bluer.  And by this rule the buildings which above a [given] line appear of the same size, will plainly be distinguished as to which are the more remote and which larger than the others.