Quote Originally Posted by hrst View Post
"Ortho" film usually means it IS spectrally sensitized (with sensitizing dye) for green wavelengths, in addition to blue. Non-sensitized emulsion is blue-sensitive only. Those are also available for some special purposes such as copy films as mentioned before in this thread.

i didn't realize there were differences, i had thought that photo paper,
was "orthochromatic" generally speaking because it was not panchromatic.

hmmm, i guess i was calling blue sensitive "ortho" without realizing there was a difference ....
so does this mean that photo paper is "ortho" and sensitive to green
as well as blue, or is it only blue sensitive or something different altogether ?

early photographic processes that just use silver nitrate ( like wet plate, dry plate ( some ) &C
would they be considered something else besides "orthochromatic"

thanks in advance !

- john