Describe the characteristics of the Caravaggisti in this artwork's Influence.
Boulogne had become a follower of Caravaggio sometime in the 1610s when he traveled to Rome. He was exposed to work from Caravaggio under the apprenticeship of Simon Vouet. While studying, he met Bartolomeo Manfredi and Cecco del Caravaggio who were also followers. He was a part of a second wave of followers based in Rome, after Caravaggio had left. As shown in the above painting, Boulogne uses tenebrism much like Caravaggio did. There is a high contrast between shade and light. The use of tenebrism and using 1/2 length figures comes from Manfredi, who Boulogne worked alongside with.   
Caravaggio was very adamant on how artists needed to use real models to paint as their presence would transfer from real life to the image. This became known as working from life, using models and props. It would bring a naturalistic element to the painting. Boulogne also used these techniques when creating his paintings whilst in Rome. These techniques can bring forth inconsistencies in paintings when working with pieces of real life to incorporate into the painting. In the instance of Boulogne's Fortune Teller, there is a lot of overlapping of body parts that can be confusing to paint. He would have to track the placement of the models that he used to know whose hand belongs to who when painting. These inconsistencies can occur if lighting is off with the models or if something slightly moves then the shading would not be correct.    
Much of Boulogne's work can be called Caravaggesque which is in reference to the style of Caravaggio.
Bartolomeo Manfredi tenebrism Caravaggio Cecco del Caravaggio Simon Vouet