Following up on the new TMAX 100 film base problem with UV transmission:
it has been suggested on a few online discussion groups that a
post-process soak in 70% isopropyl alcohol for 5 minutes with agitation
would remove the UV blocking layer of the new film. I also contacted
Kodak and was told that TMAX 100 and new Plus-X films have the
UV-blocking base but new TMAX 400 and new TRI-X do not. Kodak also did
not know of any way to remove the UV coating.
Today I tried the isopropyl soak for 5 minutes without gaining anything.
For today's test I reduced the overall UV exposure to 400 units which is
where I usually print HP5+ negatives on Cranes' paper for VDB. I
included a zone system test sheet run on HP5+ along with the sheet of
old TMAX 400 and new TMAX 100 (half of which received the alcohol
treatment.) I note that the HP5+ negative had a FBF density of 0.18 vs.
the two TMAX films which registered identical FBF values of 0.03 or
one-half stop less visible density than the Ilford film. Yet, the HP5+
negative printed out a full stop beyond old TMY and 2 stops beyond new
TMX after processing and drydown.
The image displayed at the URL below shows the test using a sheet of
VDB-coated Cranes' paper (double-coated emulsion) with the three
negatives exposed together for 400 units on the Nu-Arc:
http://my.net-link.net/~jsmigiel/images/technical/TMX_TMY_HP5.jpg
Joe
Received on Tue Oct 19 20:53:42 2004
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