The paper coatings used in that era were not a polymer like those used today either, and didn't produce a true black. "Silver gelatin" is often used in their description. Traditional papers are hard to use with modern chemicals. What might be a better solution would be to scan your negatives and use a computer program like "Photo Retouche" to produce the traditional and aged look for printing on a colour inkjet printer using Moabe's antique papers which look very much like paper from the 50's and earlier.

I do a lot of restoration work and find the only way to duplicate the look of original photos is to make them as de-saturated colour prints with a colour cast of the desired tone. I use an Epson R2400 printer exclusively for this work.

As for the taking of the pictures in the first place? Panchromatic film, processed for low contrast may do the trick. I've long held the belief you should do any contrast adjustments with paper grades, not photographic techniques. This way you keep shadow and highlight detail.

Newspaper photographers of the era often push processed their films and universally used grade 3 paper, resulting in little or no shadow detail and high key in the highlights Quite the opposite to what the paper's printer's needed!

I have the book "Life in Camelot", which is about the Life photographers history of taking pictures of the Kennedy's

Unfortunately it doesn't mention film or cameras, but if you can find information on 60s press cameras, you'll have your answers.

It seems there are 2 kinds of pictures here, one is very high contrast, almost no detail, and the other is very grainy, both suggest that they were 'pushed' somehow to get the picture, not under the best conditions.

Remember that press photos were meant to be half-toned and printed by a one color press.