Tintin in th Congo was published in the 1970's 80's-but only in B&W. Believe by both Methuen and Casterman.
Hi, dr10 - welcome to the forums!
We appreciate your enthusiasm, and know what it's like to find these forums, but would ask you to perhaps make a note of the date of some of these threads which you're replying to, especially when the point being made is speculative, rather than providing definite fresh information.
In spite of what your memory tells you, unless there is hard evidence to the contrary, it's just not right to say that Casterman or Methuen (especially the latter!) published Congo
in English in any form in the seventies.
The first black-and-white volume published in English was the Sundancer Soviets
facsimile edition, produced in 1989 to coincide with the 60th aniversary exhibition held in Chelsea.
edition that followed was secifically made the black-and-white version at the direction of Nick Rodwell, who acknowledged that there were difficulties with the tale, and that the B&W book would be better to place the story in the context of its time.
refused the book as a colour volume, because of its content, and were also reluctant to publish The Blue Lotus
, which they left until the last of the original run.
This has been confirmed by conversations with Leslie Lonsdale-Cooper and Michael Turner, in their capacity as translators of the books, and staff members of Methuen.
Until anyone can turn up an official release in English other than the above, it's got to be said that - as has happened to many of us - memory is playing tricks!