It should be noted that this technique is the most used, but it is not the only one, it is used to work on white canvases.
The most important thing to keep in mind at this stage is that we will cover the canvas with color, approaching the color of the objects but not trying to reach the exact color even, Since this layer seeks to cover the white of the canvas and the following layers will have more paint and therefore in these layers we must pay attention to our mixtures, here some points to take into account:
1.- This first layer is applied with enough turpentine, it will look like a watercolor, as you see it in the picture, the color is soft and to make it clearer it will only be more watery, at this stage we will avoid using white in the mixture Of the colors since we do not want to milky the colors from this first layer, look at the palette and the colors I use, usually only the primary ones, lemon yellow and cadmium yellow, red vermillion and carmine, blue cerulean and ultramarine, there is no white no black.
2,. We will not worry about the details, this layer does not usually cover the drawing since the oil paint is quite transparent and let us see the drawing that we have done so we can correct it if necessary.
3.- We must pay attention to the volume, we will mix colors for the shadows as well as for the local color of the object but the lights will get them by wiping out the color of the canvas and leaving the transparency of the canvas blank, just as it looks in the image.
After completing this stage we must let the paint completely dry for 2 or 3 days, then pass to the semi-paste, which will be applied with thicker oil paint using as solvent turpentine and oil in equal proportion, this layer will cover more, we can use white on the palette (as you can see in the image) and try to get closer to the color of the model as much as possible.
In the image I am painting the background and now I am painting the vase.
Note that depending on how much practice you have painting, the first layer could be very detailed and even with a smoother finish (I do not recommend it since we will cover it later), this of course depends a lot on personal taste, the technique only advises you do not use white in the mixtures and use as solvent only turpentine.