That Lewis Mileston Drama War film have many wonderful miniatures and matte paintings shots, as many of the Sam Goldwyn films, with Clarence Slifer and Ray Binger credited for the Photographic effects. In praise of the impressive visual and artistic imagery on that film we shouldn't forget the name of production designer William Cameron Menzies who is credited as associate producer.
Matte camera operator Clarence Slifer was head of photographic effect unit at many films produced by David Oselznick during the 30´s and 40´s, but also share his duties with Sam Goldwyn films. Ray Binger was another special effects cinematographer who worked also very often for Sam Goldwyn productions.
Although there is not matte painter credited at "The North Star" Clarence Sliffer used to work frequently with the same group of artists as Jack Cosgrove , Albert Simpson, Jack Shaw, and Fitch Fulton. I can only guess that the excellent matte work on that films was made by some of those artist.
Some wonderful miniature shots made for the war scenes.