One of the key illustrators working on the concept art for the Lord of the Rings films is John Howe. Howe had been creating illustrations for the book, that have featured on the front covers of them years before the films were even thought of. Peter Jackson said that there had been ’40 years of artwork done’ and that out of all the artists ‘Alan Lee and John Howe’s work impressed us the most’
In Howe’s illustrations for Lord of the Rings there is a clear contrast between good and evil forces, such as here where Samwise fights Shelob. The dark colours of the spider are confronted with the light showing the good and evil.
“The Author and his acclaimed Illustrator were their guides and only when I looked like John Howe’s Gandalf, were they satesfied that I could start to play Tolkein’s. They were right. “ – Sir Ian McKellen 
I think that this quote shows how well Howe translated Tolkein’s words into imagery, if both the actor and director of the film felt without this exact look he could not start to be the character, obviously the illustration encapsulates the all elements of the character.
Howe had a knowledge of armour having his own collection of it. (“Our garage and attic are consequently piled high with shields of every period, with lances, spears, and bits of armour, old tools, tree roots – all the flotsam and jetsam of sudden inspiration” – John Howe  Howe drew from these for ‘inspiration and reference’. He found that doing re-enactments helped to gain understanding of how armour worked on the body and thus allowing him to draw characters in armour that was appropriate and would work.
“Bestowing a level of integrity on any fantasy world means accepting aspects of it that you may never explore, constructing an alternative art history, creating artefacts and costume styles, accepting inconsistencies and blank spots, finding the best way to make it appear as a realistic universe” …” it all comes down to getting it right” 
Howe’s emphasis on ‘getting it right’ meant that his illustrations depicted Middle Earth as more of a real world than a story as all the designs are thought through as if it were real, as if depicting history. Which is the main thing Peter Jackson wanted for the films.
 Appendices, Lord of the Rings The Fellowship of the Ring Extended Edition DVD.
 Myth & Magic The Art of John Howe, Chapter Six: From Hobbiton to Mordor
 Myth & Magic The Art of John Howe, Chapter Seven: Getting it Right