What Did Cadmium Do?

I'm just curious. What was the purpose of the cadmium in old papers? What exactly did it do? What can't today's papers do because of their lack of cadmium?
Thanks.

The cadmium allowed far greater flexibility with regards to manipulation of image colour/tones of warm tone papers though over exposure and very dilute development.

These papers could be made to yield a wide range of image colours from reds through warmer browns to black purely by development.
The cadmium helped to maintain contrast with the papers, modern warm-tone papers with no Cadmium can't be manipulated by anything like as much.

Ian

I see. I did notice that such manipulations didn't seem to work with current papers, but didn't know it was because of the cadmium. I thought it had to do with emulsion thickness, incorporated developing agents, less silver, or other such things.
Do you happen to know how exactly it worked, I mean what chemical processes involving cadmium were responsible for allowing those manipulations to work?

Didn't cadmium also alow longer storage of paper? For sure it allowed better lith printing qualities (ie Kentmere Kentona)

Best,

Cor