I enjoyed using Kodak Copy film
http://www.kodak.com/global/en/professional/support/techPubs/f17/f17.pdf
From the above link:
"With most black-and-white films, the contrast of
negatives is controlled by development. However, with
KODAK Professional Copy Film, contrast in the copy
negative is controlled by both exposure and development.
Development controls the contrast of the midtone and
shadow regions of the negative (and to a slight extent, the
highlight region), while exposure primarily controls the
contrast of the highlight. For a given development condition,
as the exposure increases, highlight density increases at a
faster rate than shadow density, increasing the overall
contrast."
I do not know if it had to do with it being a ortho film, but it was very useful in getting greatly increased highlight contrast, or density in the highlights, for making carbon prints. One had to be careful using it -- a little more exposure and a little more development and the highlights would take off like a herd of wild horses. But it was great for expanding a normal contrast scene, yet keeping a nice even tonality.
I have a Kodak Copy Film negative that one needs a
very bright light behind to see anything in the highlights...they looked blocked-up. But the resulting carbon print kept wonderful detail and separation of the tones in the highlights (sun-lite granite).
I tried some of the Rollei Ortho 25...not the same stuff as the Kodak Copy and I did not have enough of it to tame the horses properly.
