"We strongly advise those desirous of doing artistic work to begin by studying tone, expose (always giving two exposures to each subject) on selected subjects, especially fit for the study of tone; for example, a figure in a white dress against a white background, another in a black dress against a black background, and then a white dress against a black background, and a black dress against a white background; some white flowers against a sheet of white paper; yacht-sails against the sky; faces against the sky; black velvet in bright sun-
shine, and on a grey day; yellow flowers (with orthochromatic plates) on a white background. In short, the student should think of all the possible harmonies and discords that can be found indoors and out of doors, and he should, before taking a plate, make a mental translation of the subject into black and white, and put on paper roughly, with a piece of charcoal, what he expects to get, by drawing rough masses in tone of the subject. He should at first think nothing whatever of composition, or the more poetical qualities of a picture; but simply study tone, and by this he will learn thoroughly exposures and development. Let him eschew all requests to take portraits, dogs, horses, parks, and what-nots; but let him always study tone. When he has mastered tone, and with it exposure and development, he knows the most difficult part of his technique and practice, let him then proceed to picture-making. In this early stage let him take anything and everything that is a study of tone, and let him take it anyhow, no posing, no arrangement, and when he knows his metier thoroughly let him destroy all these early plates ruthlessly. We strongly advise him to give away no prints of early work, or he will most surely rue the day when he did so. In our opinion a year is not too much in which to work in this way, both in doors and out of doors, in studios and out, with shutter and without, before there is any attempt to take a portrait or picture of any kind."
—Peter Henry Emerson
—from Naturalistic Photography for Students of the Art, 1889
(Available in its entirety from the Internet Archive)
Mike (Thanks to R. Stafford)