Ken
It all depends on what you want in the final print. This is a subject on
which people have different views !
My own is that I look for a wide range of tones, up to a d max of 2.4, say
for highlight detail in the whites, with fine gradation across the range.
I found, after looking at Frederick Evans's negatives that there were only
three graphic arts films that would do the job, Agfa N31P , Kodak Sep Neg 2
and Gravure Positive. The first two went out of production last summer but
people have stocks. I am not sure of the position on Gravure Positive.
But,for me, the best answer is Ilford FP4 which I have tried with a range
of developers only to discover that the best one out of a bottle is
Ilford's PQ Universal developer which is I believe marketed in the States
as Universal. This will give very good results if you over expose by two
stops and over develop by
50%; this gives a development time of 135 seconds. If you want the very
finest results develop in acid amidol( if you want to pursue this I will
search out relevent postings for you but they are in the archives) for much
the same times. The film is available up to 11 x 14.
Of courseit is possible to use lith films developed to continuous tone but
my own view is that, if you are going to spend money on platinum to get the
best, it seems to be spitting into the wind to compromise on the film as if
you get the negative right more than half the battle is won..
Terry King