In the downpour scenes showing the Rashomon Gate, Akira Kurosawa found that the rain in the background simply wouldn't show up against the light gray backdrop. To solve this problem, the crew ended up tinting the rain by pouring black ink into the tank of the rain machine. The ink is clearly visible on the Woodcutter's face towards just before the rain stops.
This film is often given credit for the first time a camera was pointed directly at the sun. In Akira Kurosawa's biography, he gives credit to his cinematographer for "inventing" it and himself for using it, but years later, during commentary that preceded the TV showing of the film, the head of the studio claimed credit, which Kurosawa bitterly denies.
During shooting, the cast approached Kurosawa en masse with the script and asked him, "What does it mean?" The answer Akira Kurosawa gave at that time and also in his biography is that Rashomon is a reflection of life, and life does not always have clear meanings.
In the wife's vision, the music used was only available during post-production. Akira Kurosawa and his editor was amazed when they found that the music corresponded almost perfectly with the action on the screen, and thus they didn't need to change the scene to make it match the music.
The title "Rashomon" actually refers to the wraparound segments, from a Akutagawa story set at the Rashomon Gate of Kyoto. The actual story related in the film instead comes from another tale by Ryûnosuke Akutagawa, "In a Grove".
Even during high noon the parts of the forest that the crew needed to shoot in were still too dark. Rather than use a regular foil reflector, which did not bounce enough light, Akira Kurosawa and cinematographer Kazuo Miyagawa opted to use a full-length mirror "borrowed" from Daiei's costume department. The crew bounced light from the mirror through leaves and trees to soften it and make it look more like natural sunlight. Miyagawa later called it the most successful lighting effect he had ever done.
The title of the film has recently been added to the Oxford English Dictionary as describing "...resembling or suggestive of the film Rashomon, esp. in being characterized by multiple conflicting or differing ... interpretations."
In his autobiography, Akira Kurosawa recalled that one of the biggest problems his crew encountered while filming in the forest was that slugs kept dropping out of the trees onto their heads. The cast and crew had to constantly slather themselves with salt to keep the slugs off.
When the film was released internationally to rave reviews, many speculated that Akira Kurosawa was influenced by Citizen Kane in the element of flashbacks that ultimately provide conflicting accounts of events. However, Kurosawa didn't even see Orson Welles's film until several years after the release of 'Rashômon'.