AN (Anti-Newton) glass question

"____" wrote in message
...
In article , jjs
wrote:

Yes, as long as it is an anti-newton negative carrier.

I'm glad that was brought up. Quite frankly, I just
presumed the negative
carrier in question would need anti-newton glass. I will
describe it and
perhaps someone can enlighten me. The glass is for the
Saltzman 8x10
enlarger. The carrier works with two plates of glass
(exactly 8x10") to
sandwich the negative. There is nothing whatsoever to
separate the glasses,
except the negative. One removes the lower glass, does
what he can to remove
dust, replaces the glass, and swings four tension clips
over the edges of
the glass.

Requires AN glass, no?

Thank you all!

Ok for you, I just pulled my Omega 10x10 carrier out of
the enlarger
and it has two sheets of standard optical glass but not
AN. To my
knowledge AN appears with a Matte surface unlike standard
optical grade
glass. It (AN) will look less than perfectly clear. Imop &
Perhaps
Richard K. can corroborate AN is only needed with a
Condenser housing, I
have an Omega diffused Halogen one of three known to
exist.

Newton's rings are most obvious where the light source
is collimated which is at least partially the sase when a
condenser source is used. A diffusion source will not
usually display the rings.
Most condenser enlarger lamphouses are somewhere between
diffuse and a true specular source which requires a point
source as well as a means of collimation. The typical
enlarging lamp is a fairly large and quite diffuse source
(for instance an opal lamp) so the resulting light is
partially diffuse and partly collimated.
Saltzman also made a glassless negative carrier that
held the negative flat by spring tension by means of clips
on the carrier.

---
Richard Knoppow
Los Angeles, CA, USA

"Richard Knoppow" wrote in message
...

Newton's rings are most obvious where the light source
is collimated which is at least partially the sase when a
condenser source is used. A diffusion source will not
usually display the rings.

You just saved me $90. I owe you. Truly.

The lamp housing, which was originally dual condensers, is missing, and we
plan to replace it with a diffusion source. So plain optical glass it shall
be.

In article ,
____ wrote:

Ok for you, I just pulled my Omega 10x10 carrier out of the enlarger
and it has two sheets of standard optical glass but not AN. To my
knowledge AN appears with a Matte surface unlike standard optical grade
glass. It (AN) will look less than perfectly clear. Imop & Perhaps
Richard K. can corroborate AN is only needed with a Condenser housing, I
have an Omega diffused Halogen one of three known to exist.

No. Under some conditions -- atmospheric and of the negative -- you'll
see Newton rings with this glass carrier. I know because I have one.

To make one of my negatives printable I had to replace the top glass in
my 10x10 Omega carrier with AN glass and the bottom glass with a piece
of anti-reflective coated glass from a frame shop. With that done, the
problem was considerably lessened, though not eliminated entirely.

The best solution is a tension carrier like the pin-register carriers
Fotar used to make for their enlargers -- actually the only 8x10"
tension carriers I've ever seen. In 4x5" the Beseler Negaflat, of
course, was fairly common.

--
Thor Lancelot Simon

"The inconsistency is startling, though admittedly, if consistency is to
be abandoned or transcended, there is no problem." - Noam Chomsky

In article ,
(Thor Lancelot Simon) wrote:

In article ,
____ wrote:

Ok for you, I just pulled my Omega 10x10 carrier out of the enlarger
and it has two sheets of standard optical glass but not AN. To my
knowledge AN appears with a Matte surface unlike standard optical grade
glass. It (AN) will look less than perfectly clear. Imop & Perhaps
Richard K. can corroborate AN is only needed with a Condenser housing, I
have an Omega diffused Halogen one of three known to exist.

No. Under some conditions -- atmospheric and of the negative -- you'll
see Newton rings with this glass carrier. I know because I have one.

To make one of my negatives printable I had to replace the top glass in
my 10x10 Omega carrier with AN glass and the bottom glass with a piece
of anti-reflective coated glass from a frame shop. With that done, the
problem was considerably lessened, though not eliminated entirely.

The best solution is a tension carrier like the pin-register carriers
Fotar used to make for their enlargers -- actually the only 8x10"
tension carriers I've ever seen. In 4x5" the Beseler Negaflat, of
course, was fairly common.

Is your 10 x10 the dichroic lamp house or a condenser? The Dichroic is a
1,000 watt quartz halogen source. My diffused halogen is half that.

--
Reality is a picture perfected and never looking back.

In article ,
____ wrote:

Is your 10 x10 the dichroic lamp house or a condenser? The Dichroic is a
1,000 watt quartz halogen source. My diffused halogen is half that.

It's the dichro. Someone had put some funny low-wattage, long-life
bulbs in there, though -- when one finally blew and I had to replace
them all, it ran so much hotter it melted off some black contact paper
which had been used to shim the assembly for light tightness!

My Chromega 10x10 head is actually on a Durst Laborator 138 which was
one of several adapted for use printing highway signs by a company in
Toronto. It came with motorized raise/lower and focus and a 50" coiled
between the motor control box and the remote control -- it's hard to
imagine what it must have been like to use in that configuration. The
company sold them off on eBay as they wore out and converted to
Lightjet units, I believe. I got one of the earlier ones, so I probably
overpaid, but it's worked well for me for about 10 years now though it
has some loose bits and other quirks I would think would have made it
annoying for daily commercial use.

--
Thor Lancelot Simon

"The inconsistency is startling, though admittedly, if consistency is to
be abandoned or transcended, there is no problem." - Noam Chomsky