While there have been evolutionary changes in both D-76 and Tri-X over the past 50 years,
as PhotoEngineer has demonstrated, they have been minor and don't account for much difference in an image made today, and one made in 1960, 1970, or 1980.
If you want to emulate the Sieff "look", you might consider what HAS changed.
First, look at the equipment. A state of the art Nikon FTn of 1970, with its cds meter and mechanical shutter, it is downright primitive compared to electronic shutters and meters today. It was essential to NEVER underexpose a shot, so - by today's critical standards - most shooters made overexposed images.
Temperature control in the darkroom in 1970 was done, in the BEST labs, with a couple big, and expensive, Kodak Process thermometers. Even so, it is easier today to have optimally controlled baths in your basement lab than in the best labs in New York or Paris of 1970.
If one souped their own film, it was nearly always D-76 1+1. Everybody had their own technique, and since they were working pros, consistent results were more important than 'perfect negs'.
If you had a lab soup your film, it was likely to be done in a mature replenishment line which gave subtle results which were, and are, impossible to reproduce in a home darkroom.
Lighting was different. Often, photofloods or more readily available PARs were used to replace or augment available light. Shooting under uncorrected tungsten light gives a different color response than under daylight. Electronic flash was harder to work with then. Small units had low power, and before thyristor circuits, their output varied considerably. Studio flash was heavy, and tended to stay in the studio. Film was often "pushed" to 1600, which made empty blacks and hot highlights.
So, compensating for the myriad technical difficulties, any shooter had to overexpose a little, which was sometimes magnified by equipment, and either underdeveloped or overdeveloped as needed. Bleaching film, and prints, was essential more than we'd like to remember.
But the most important variables were the ZEITGEIST and the shooter. Crawl into Sieff's head, and try to get was he was looking at, and what he was seeing. Try to understand the time he made his pictures, and what he was trying to accomplish.
Finally, Sieff and all the shooters of the day were shooting for magazine reproduction. The tonal response, at the best publications, was quite limited. A black was determined by how much ink the press could lay down, and a white determined by the paper stock. Photographers made a large amount of their income from secondary usage of the images, so Life or Match might pay for all the expenses of your big shoot, and give you the chance to shoot a lot of film that other clients might be able to use, but your rent and booze money usually came from the smaller magazines that had good, but inferior, reproduction than did the biggest publications. SO, you always composed your pictures in 5 basic tones: black, white, and 3 contrasting shades of gray. If a picture was placed in a good newspaper, much subtlety was lost but the picture looked good. If it ran in a high class magazine, it looked even better.
So. While "LOOK" of the '50s, '60s, and '70s was partly due to Tri-X and D-76,
and D-76 and Tri X have changed a bit since each decade,
the film and developer isn't the issue. HOW they were used,
and what had to be accomplished by a specific shooter is everything.
Visit the Magnum website for a comparative look at great images for publication since WW2:
http://www.magnumphotos.com/Archive...&SP=photographers_list&l1=0&XXAPXX=SubPanel10
