"extended red sensitivity" in B&W films

Some of the films on the market have "extended red sensitivity" as

part of their makeup. Supposedly this works to give skies & areas

the same or close to the effects one gets with a yellow filter or

even an orange one.(per some posters/users)

 

What does this do to the shadows in some scenes? If it darkens skies

containing a lot of nice blue what does it do to the blue in the

shadows? Darken too much? Do you lose shadow detail using these

films?

 

If it darkens them, is this controllable or are you at the mercy of

the film?

Extended red sensitivity doesn't darken anything. It merely lightens a portion of the red spectrum such as the red blemishes on skin. It tends to smooth those blemishes and make skin much more appealing. Women tend to benefit from being photographed with films such as plus x. Men tend to look better using a film without this red sensitivity. At least those who prefer a more rugged appearance. I use a green filter when photographing men for this effect. You can get the same effect with a light red flter as with shooting plus x..