“The observer usually will see what his fears and hopes and learning teach him to see. But if he can escape these demands that hold up a mirror to himself, then perhaps some of the implications of the work may be felt. But whatever is seen of felt it should be remembered that for me these paintings had to be something else. It is the price one has to pay for clarity when one’s means are honoured only as an instrument of seduction or assault.”

Quote from "The Awe-Struck Witness" in TIME magazine (28 October 1974) http://www.time.com/time/magazine/article/0,9171,908926-1,00.html and in "On the Brink: The Artist and the Seas" by Eldon N. Van Liere in Poetics of the Elements in the Human Condition: The Sea (1985) ed. Anna-Teresa Tymieniecka
Variant translations:
The artist should not only paint what he sees before him, but also what he sees within him. If, however, he sees nothing within him, then he should also omit to paint that which he sees before him.
As quoted in German Romantic Painting (1994) by William Vaughan, p. 68
undated
Context: The artist should not only paint what he sees before him, but also what he sees in himself. If, however, he sees nothing within him, then he should also refrain from painting what he sees before him. Otherwise his pictures will be like those folding screens behind which one expects to find only the sick or the dead.

translation from the original Dutch, Fons Heijnsbroek
version in original Dutch (citaat van zijn brief aan nl:Jan Veth, in het Nederlands:) Bosboom heeft net zoo goed als een ander wel eens dingen afgepeuterd om aan geld te komen. daar ontsnappen maar heel weinig menschen aan.. .Het is bijna onmogelijk dat een artist die niet de gaaf heeft om tegelijk voor de verkoop te werken altijd heeft goede dingen te maken. omdat hij als hij geen geld heeft het moet verdienen. En hij zich zal moeten inspannen. Voor iets waar hij minst voor voelt. Dat nooit nalaten kan.. .De voorbeelden zijn voor 't grijpen. Als je soms iets over hem mocht schrijven hoop ik dat je dit ook in aanmerking zult nemen.
quote of Breitner in a letter to Jan Veth, Amsterdam, Fall 1891; original text in RKD-Archive, The Hague https://rkd.nl/explore/excerpts/80
Jan Veth wrote an memorial on Johannes Bosboom, shortly after Bosboom's death
1890 - 1900

Source: Clockwork Prince

Quote from his writings Thoughts on Art, Caspar David Friedrich; as cited in Letters of the great artists – from Blake to Pollock, Richard Friedenthal, Thames and Hudson, London, 1963, p. 33
undated

Source: The Magician King

Source: The Maltese Falcon

Source: Resurrection (1899), Ch. 28

Light (1919), Ch. XIX - Ghosts
Context: Among some papers on my table I see the poem again which we once found out of doors, the bit of paper escaped from the mysterious hands which wrote on it, and come to the stone seat. It ended by whispering, "Only I know the tears that brimming rise, your beauty blended with your smile to espy."
In the days of yore it had made us smile with delight. To-night there are real tears in my eyes. What is it? I dimly see that there is something more than what we have seen, than what we have said, than what we have felt to-day. One day, perhaps, she and I will exchange better and richer sayings; and so, in that day, all the sadness will be of some service.

Source: Real Presences (1989), I: A Secondary City, Ch. 3 (p. 9).