Please keep us updated on what you find ...

Hi,

Am I correct in assuming that the placement of the Newtonian glass would
be on the top and plain glass on the bottom supporting the neg or do you
need NG on both sides?  Besides my 4x5 negs, I would also like to use it
for 6x6, 6x7, 6x9, and 4x4, and maybe 35mm.  Instead of six neg holders
laying around, I would just have that one that one.  This would also
complement the 4 bladed cropping gizmo just below the bottom condensor
(using an Omega D2V) and above the neg holder.  This way, I can crop the
light reaching the neg.  Ideas, criticisms?

Bogdan

Well I can, from my practiacal work, once i discovered that
something is wrong with a smooth light grey sky on a print from
6x9 b/w negative, it stroke me like a thunder, that horrible
anti-newton glass, it left it's mark; the sky was all grainy...
so i removed it and all went just fine from then on...
So flatten your neg's as much as possible and use glassless
carriers...

I sure can't see any grainy effect.

...

...

jan2205 from Lloyd Erlick,

These remarks lead me to think there is a variation in
the quality of anti-Newton ring glass available on the
market. Think how large the audience would be for a
magazine article comparing all the brands of
anti-Newton ring glass! (Should I approach Time? Or
Newsweek?)

I worked with glassless negative carriers for many
years. Eventually in my old age I bought my first new
enlarger, a Durst L1200. Wish I'd bought one when they
first came out! I splurged and bought a set of
glassless inserts for the negative carrier, plus a set
of anti-Newton glasses.

I then proceeded to work glassless for several years,
until comments by Bob Saloman (another participant on
this newsgroup) goaded me into trying out the AN glass
inserts. (Bob's remarks have gone beyond dust. He
asserts there is no point carrying out exacting
alignment on an enlarger without glass carriers,
because negative curvature will swamp any improvement.
He also says there is no point improving the lens
beyond a strictly ordinary level for the same reason.)

I ended up very unhappy that I had waited so long. So
many prints to re-make ... impossible. I can only say
I'm glad I mainly work with a black background, so the
corners and extremities of most of my prints can be out
of focus and not show. Because once I put the glass
inserts in, my prints were suddenly pin sharp corner to
corner, edge to edge, and with next to no effort. The
glass really does make the negative flat, and it really
does matter. Why shouldn't it? Didn't I pay fancy money
for all those fancy enlarger lenses? Why would I expect
the curvature of a negative in a glassless carrier to
go without being noticed by the lens? I can see the
curvature at the edges perfectly clearly just by
looking! It's only logical that a really good
Rodenstock lens would see the same thing, so what was I
thinking?

Anyway, the improvement I've seen has not had any
downside at all in results. The Durst AN glass inserts
absolutely do not contribute grain or structure or
mottling or graying or texture or any other word to the
final prints. They are a distinct improvement, only,
with no tradeoff in the look of the final print.

The downside, if you can call it that, is that one must
keep the glass sheets clean. Much has been made of this
so-called difficulty, but in reality it is no more work
than keeping the enlarger lens clean. The solution is
simple: don't let it get dirty. I don't have to clean
my lens more often than quarterly, in fact probably
more like yearly. My AN glasses are a bit more likely
to get touched by my clumsy hands, and maybe a few
flakes of dead skin fall off my face onto them twice a
decade, but it's a small price to pay for *flat*
negatives above my expensive *flat* field optics.

I find three things used together are useful in
cleaning glass negative carriers, and keeping them
clean:

-a lens polishing cloth of the sort provided with new
eyeglasses. I have one reserved for my AN glasses, in a
clean container next to my enlarger. It is very rarely
used, but handy when needed.

-a compressed gas type of dust blower. I keep a tank of
nitrogen, because I use a lot. But the small hand held
size cans of refrigerant gas, or whatever they package
in them, do the job, too, as would a compressor and
tank setup or even a rubber squeeze bulb. I don't blow
on my negatives because it's just gambling with saliva.
I have taken to taping an extreme edge of my negative
to the outer edge of the negative carrier (not the
glass) to hold it relatively in position, and then
blasting the whole thing with nitrogen. Sometimes one
hears that this is not a wise procedure, because "all
you are doing is pushing the dust around" or some such.
It is a relatively true statement if static electricity
is a factor (see below) but as long as the tiny specks
of dust are pushed around onto the floor, I'm happy. A
clean darkroom is a happy darkroom, true, but really
only the light path *must* be clean.

-proper humidity in the darkroom so dust specks are not
attracted to or held onto the AN glasses by static
electricity. Electrostatic forces can drive you mad in
the darkroom. A relative humidity (RH) readout device
of some sort is an essential darkroom tool. The ones
sold at Radio Shack are more than good enough, because
we do not need exact correctness compared to objective
reality. We only need an approximation and consistency,
so we can adjust the humidifier, which is also an
absolute necessity (along with its sibling, the
dehumidifier, in the climate where I live...). As long
as RH is something like 50 per cent (say 45 to 60) dust
is not held or attracted, and humidity is not too high.
Controlling RH within a range that wide is easy and
cheap (as opposed to say a range of 49.5 to 50.5, which
would cost ...). Note that the appearance of Newton's
rings depends a lot on surface characteristics of
everything sandwiched in the carrier, plus the amount
of moisture in the air (RH again). Too high RH will
promote rings, so it's a balance. It's rather
convenient that the so-called human comfort range for
RH works out to be an appropriate balance for all these
factors (at least for the ordinary films I use,
everything could be different for specialized films).

To return to the original question, a source of
anti-Newton glass, I'd have to say get it from a source
known to be reliable. That's pretty vague, I know, but
crucial to the quality of final prints. There is no
need for AN glass to degrade prints. The statement, 'Do
not use "antinewton" glass for serious job', is the
reverse of the truth.

Regards,
--le