Technical difficulties in transcribing the movie to dvd.

According to the blurb printed inside the box, the people who transcribed this movie had some difficulties on account of the original techniques employed when making the film (movie). Many of the scenes appear to me rather dark and ill-lit but the story itself is an early le Carre one and as a fan of this author, I tolerate it. The early scene where one of the school masters seizes an unfortunate pupil by the ear would be considered an actionable assault today. It reminds me of my schooldays in the 40' and 50's when such conduct was commonplace. It's a rather dark tale in both senses...........