I am interested in learning about enlarging negatives in the 6 x 9 format. I recall long ago that ease of enlarging stopped at 6 x 7 and that with the 6 x 9 size, the number of available enlargers decreases dramatically. In other words, the 6 x 9 format is much more rare to print due to the need of a special type enlarger. Is this true? If I am interested in printing at home in future, should i stay with 6 x 7 or smaller? I know nothing about enlarging and am only going on a long, distant memory. Thank you for your help!