We are back to the painting of the dog under the plum tree. When we looked at the superb brushwork all seemed rather simple. But with a second look we notice, the white plum blossoms are a little bit brighter than the background. Just a little bit, so that we can barely notice it. The same could be seen with the dog.
For this little, but fine effect, the master has put a layer of very light coloured ink all over the background!