Letters On Landscape Photography. The student must have a good knowledge of what a negative really ought to be. He must also learn how the values of nature should appear in a print, and he will find that his mechanical means will enable him to get what he desires. This power of seeing values belongs to the art side of photography, and is not so easily attained but what I want to point out is, that when you can see, there is no great difficulty in mastering the mechanical means of representing what you see. I do not, therefore, go into the preliminary chemical rudiments of photography, but assume your knowledge, and leave you to perfect it from any of the manuals now published...