Roux
Roux () is flour and fat cooked together and used to thicken sauces. Roux is typically made from equal parts of flour and fat by weight. The flour is added to the melted fat or oil on the stove top, blended until smooth, and cooked to the desired level of brownness. Butter, vegetable oils, bacon drippings or lard are commonly used fats. Roux is used as a thickening agent for gravy, sauces, soups and stews. It provides the base for a dish, and other ingredients are added after the roux is complete.
J. F. Roux
The painting process itself was more painstaking than is typically associated with working en plein air. Roux’s more naturalistic style and desire to capture the actual form and tone of the landscape he was painting precluded the impassioned projection of his own emotions onto the canvas in a single session. For Roux, the landscape itself was the bearer of emotion. At least, the painting had to represent something that the viewer could recognise as the essential nature of the subject. That required him to paint methodically over several days, slowly building up the formal features and tonal effects he wanted to capture. 
Apart from landscape painting, which forms the bulk of his artistic output, Roux was also an accomplished portrait and still-life painter. His portrait work began on the farm in Southern Rhodesia with studies of his acquaintances at the mission. In contrast to many European depictions of African subjects, his portraits are not caricatures of ‘exotic natives’, but fully sympathetic renderings of fellow human beings. To the extent that the colonial encounter is present at all in these paintings, it comes through in his subjects’ barely perceptible melancholy. But these are nevertheless people with autonomous lives and, in the case of the younger ones, unknown futures yet to be lived in all their complexity.