I will soon have finished another drawing [= watercolor], in the spirit as Den Tessaro [art-seller in Antwerp] wished another one, that is 'airy' and… - Willem Roelofs

..when making a painting after a study, it costs me a lot of effort to follow this study very well. One is very much inclined to make something different, so-called better, and that's why people usually get confused. A good outdoor-study has a breath of nature in it which must not be neglected or destroyed. You have to get everything out of that study and not just a third or half. If you can really improve one or the other: a la bonheur, but otherwise it is advisable to follow the study obediently as a guide. (translation from original Dutch: Fons Heijnsbroek)

(original Dutch: citaat van Willem Roelofs, in het Nederlands:) Het doel, het streven van de kunst, is als dat van de muziek, te ontroeren; in onze geest gewaarwordingen te doen ontstaan..

Then make those studies outside. With the utmost simplicity you try to get rid of all the so-called manners, and try in one word to follow nature with feeling, but without thinking about the works of others. (translation from original Dutch: Fons Heijnsbroek)