Same problem; no one makes E-4 any more. There is a modern equivalent
called EA-5, which is run at high temperature for high speed aerial
film processing, and ME-4, which is used for some motion picture films.
EA-5 at 85 degrees F is essentially identical to E-4. There is a lab
in Colorado, Rocky Mountain Film, that will do single rolls in EA-5,
for about $20 each. The other alternative is to make or buy some EA-5
prehardener and neutralizer, which makes the emulsion able to withstand
further processing, and then immediately run it in E-6. (A major
difference between E-4 and E-6 films, maybe *the* major difference, is
that the E-4 films are not hardened in manufacture while E-6 films are.)
The recipes for the prehardener and neutralizer are on Bengt Halliger's
homepage at http://math.liu.se/~behal/photo. Nothing particularly exotic
in either chemical except hydroxylamine sulfate in the neutralizer. I
am waiting for some of this from Formulary and will then try it with
some aerial Ektachrome I have.

вы выбрали, вероятно, самый сложный и дорогой способ протестировать фотоаппарат искра