This is a still from a private home movie. The '14' is clearly black when compared to the red devil on the cowling. Furthermore, 5./JG 52 had ceased using red markings around mid-April 1940... No amount of checking shades in Photoshop will disprove these historical facts...
This particular eyewitness also stated that when he viewed Werner Bartels' aircraft it was sporting a full painted yellow rudder... It clearly didn't if it was shot down on 24 July 1940... No onsite reports at the time mention a yellow rudder and they would have mentioned this feature if it was there because this would have been the first aircraft to be seen having a yellow rudder... The official order to paint the tips of the rudders, wings and tail wasn't sent to units until 10 August 1940 and fully painted yellow rudders didn't start to appear until the last week of August 1940... The eyewitness accounts of this particular researcher are totally unreliable...