The Truth in Painting

In Derrida's essay Passe- Partout, Cezanne is saying that painting can render the truth, and Derrida is saying that truth has been the provenance of speech-acts (philosophy). So Cezanne is saying that painting can be a means for searching for the truth, as language is a means for searching for the truth in philosophy. Cezanne also seems to be saying that it is the act of painting, the process of seeing and recording one's sensations before nature the truth becomes possible. This probably is leading to the famous Derridean phrase "There is nothing outside the text" from On Grammatology. I see the ghost of Greenberg hovering nearby.