Anti-Newtonion glass for 4x5

Hello,

I have a Omega DIIv and want to change the original 2 glass plates on
the 4x5 negative holder. I haven't used it because both pieces of glass
which scratch marks on them; instead I use a glassless 4x5 holder. I
was told that I should install Anti-Newtonian glass. What is the
difference between regular glass and Anti_Newtonian glass? Unclear on
the concept...

If there is a significant difference, I would like to replace them with
Anti-Newtonian glass. Is there still a source for this glass, cut to
proper size? Thanks.

Regards,
Bogdan
--
__________________________________________________ ________________
Bogdan Karasek
Montréal, Québec e-mail:
Canada

"Wovon man nicht sprechen kann, darüber muss man schweigen"
"What we cannot speak about we must pass over in silence"
Ludwig Wittgenstein
__________________________________________________ ______________

In article ,
Bogdan Karasek wrote:

Hello,

I have a Omega DIIv and want to change the original 2 glass plates on
the 4x5 negative holder. I haven't used it because both pieces of glass
which scratch marks on them; instead I use a glassless 4x5 holder. I
was told that I should install Anti-Newtonian glass. What is the
difference between regular glass and Anti_Newtonian glass? Unclear on
the concept...

If there is a significant difference, I would like to replace them with
Anti-Newtonian glass. Is there still a source for this glass, cut to
proper size? Thanks.

Regards,
Bogdan

You can or probably could get the glass through any good glass supplier,
but would need to be cut to specified size if its and old carrier.
There are lots of variations on our Omega carriers-so the new
configuration may not apply to yours.

The idea behind AN glass is that the glass has a slight texture- a
series of ridges that hold the negative away from the glass surface
thereby preventing two smooth surfaces and eliminating the concentric
Newton rings.

The glass is used on the topside only of the carrier because if placed
on the bottom side as well will print the pattern of the ridges onto
the photo paper it will also produce a fuzzy image.
--
Carry me caravan take me away, take me to Portugal take me to Spain,Andalucia with fields full grain. I have to see you again and again. www.gregblankphoto.com

In article ,
Greg \"_\" wrote:

The glass is used on the topside only of the carrier because if placed
on the bottom side as well will print the pattern of the ridges onto
the photo paper it will also produce a fuzzy image.

Actually, the best solution I've found is to use anti-newton glass --
available from frame shops as "anti-glare" or "no-glare" glass; it is
acid-etched to have a very very slight stippling -- above the negative,
and coated glass, also available from frame shops, under it. If you
are doing color work you will want to get the fancy low-iron coated
glass for best results, and perhaps use it both above and below the
negative.

Frame shops often sell the "Denglas" brand of coated glass. A large
shop can probably even seam the edges of this for you after cutting it
to size so that you do not risk cutting your fingers when you install
it in the carrier or remove it for cleaning.

--
Thor Lancelot Simon

"We cannot usually in social life pursue a single value or a single moral
aim, untroubled by the need to compromise with others." - H.L.A. Hart

Thor Lancelot Simon spake thus:

Frame shops often sell the "Denglas" brand of coated glass. A large
shop can probably even seam the edges of this for you after cutting it
to size so that you do not risk cutting your fingers when you install
it in the carrier or remove it for cleaning.

In the neverending advocacy campaign for DIY, this is trivially easy for
anyone to do at home with a piece of 600-grit wet-or-dry silicon carbide
paper and water.


--
Save the Planet
Kill Yourself

- motto of the Church of Euthanasia (http://www.churchofeuthanasia.org/)

In article ,
David Nebenzahl wrote:
Thor Lancelot Simon spake thus:

Frame shops often sell the "Denglas" brand of coated glass. A large
shop can probably even seam the edges of this for you after cutting it
to size so that you do not risk cutting your fingers when you install
it in the carrier or remove it for cleaning.

In the neverending advocacy campaign for DIY, this is trivially easy for
anyone to do at home with a piece of 600-grit wet-or-dry silicon carbide
paper and water.

Sure, you can edge glass yourself. However, you're going to have to deal
with a frame shop to get the coated glass in the first place, unless
you're buying a huge quanitity or want to pay Edmund Optics style prices;
so you might as well pick a frame shop that has an edge seamer, and then
you don't have to do any sanding; they can just make the edge safe for you
when they cut it.

--
Thor Lancelot Simon

"We cannot usually in social life pursue a single value or a single moral
aim, untroubled by the need to compromise with others." - H.L.A. Hart

In article ,
(Thor Lancelot Simon) wrote:

In article ,
Greg \"_\" wrote:

The glass is used on the topside only of the carrier because if placed
on the bottom side as well will print the pattern of the ridges onto
the photo paper it will also produce a fuzzy image.

Actually, the best solution I've found is to use anti-newton glass --
available from frame shops as "anti-glare" or "no-glare" glass; it is
acid-etched to have a very very slight stippling -- above the negative,
and coated glass, also available from frame shops, under it. If you
are doing color work you will want to get the fancy low-iron coated
glass for best results, and perhaps use it both above and below the
negative.

Frame shops often sell the "Denglas" brand of coated glass. A large
shop can probably even seam the edges of this for you after cutting it
to size so that you do not risk cutting your fingers when you install
it in the carrier or remove it for cleaning.

Its a good solution-you give. Noting however: "coated" does not equate
to Ant newton,.....but still a good idea never the less for the bottom.
--
Carry me caravan take me away, take me to Portugal take me to Spain,Andalucia with fields full grain. I have to see you again and again. www.gregblankphoto.com

HI,

I just want to thank all the people who responded. Some very
interesting comments and information. Didn't know that you only put an
AN on the top and regular good quality glass on the bottom. I've been
shooting 4x5 on and off for the past few years, mostly do 120 and 35,
but as I go on, I'm drawn to the larger format, bought a 5x7 Elwood
enlarger which will differently need an AN, and have shot about 100 8x10
negs. I'm also drawn to the palladium print and thought that the AN
would improve the quality of the negative. I have a heat absorbing glass
in the filter drawer on my DIIv. But still, I like the idea of using
just one neg holder for 35, 4.5x6, 6x6, 6x9 and 4x5 is very alluring.
Point taken about possible dust problems but I'm very scrupulous,
always "dust" both sides of the neg with compressed air and dust out the
condensers at least once a month, if not more often if I'm using it
heavily. So the dust problem would be taken care of. Another factor
that I have to consider is that I often work with the same negative all
day and night. Must take a beating being under the "lights" so long.
????. The AN might help there???

Anyway, You have been very helpful and I Thank You!

Regards,
Bogdan

Greg "_" wrote:
In article ,
(Thor Lancelot Simon) wrote:


In article ,
Greg \"_\" wrote:

The glass is used on the topside only of the carrier because if placed
on the bottom side as well will print the pattern of the ridges onto
the photo paper it will also produce a fuzzy image.

Actually, the best solution I've found is to use anti-newton glass --
available from frame shops as "anti-glare" or "no-glare" glass; it is
acid-etched to have a very very slight stippling -- above the negative,
and coated glass, also available from frame shops, under it. If you
are doing color work you will want to get the fancy low-iron coated
glass for best results, and perhaps use it both above and below the
negative.

Frame shops often sell the "Denglas" brand of coated glass. A large
shop can probably even seam the edges of this for you after cutting it
to size so that you do not risk cutting your fingers when you install
it in the carrier or remove it for cleaning.


Its a good solution-you give. Noting however: "coated" does not equate
to Ant newton,.....but still a good idea never the less for the bottom.

--
__________________________________________________ ________________
Bogdan Karasek
Montr‚al, Qu‚bec e-mail:
Canada

"Wovon man nicht sprechen kann, dar�ber muss man schweigen"
"What we cannot speak about we must pass over in silence"
Ludwig Wittgenstein
__________________________________________________ ______________

In article ,
Greg \"_\" wrote:

Its a good solution-you give. Noting however: "coated" does not equate
to Ant newton,.....but still a good idea never the less for the bottom.

If you mean that coated glass isn't the same stuff a photo supplier will
sell you as "anti-newton glass", that's correct; the acid-etched "anti
glare" glass sold by frame shops is, as far as I can tell, the exact
same product, however.

But if you mean "coated glass doesn't _work_ as anti-newton glass",
you're not right. Newton's rings are an interference pattern; the
waves that are interfering are those reflected back and forth between
the surface of the negative and the surface of the glass. Coated glass
reduces the amplitude of each reflection from its surface by about 95%
compared to uncoated glass; so in fact it is a very effective way to
avoid Newton's rings.

The acid-etched glass works in a different way (by increasing the distance
between the negative and the glass, and by providing a diffuse reflection
that does not give the interference pattern), and is cheaper. I do not
think it works much better, though -- but since you can't use it
below the negative, coated glass is your only option there anyway.

--
Thor Lancelot Simon

"We cannot usually in social life pursue a single value or a single moral
aim, untroubled by the need to compromise with others." - H.L.A. Hart

Thor Lancelot Simon spake thus:

In article ,
Greg \"_\" wrote:

Its a good solution-you give. Noting however: "coated" does not equate
to Ant newton,.....but still a good idea never the less for the bottom.

If you mean that coated glass isn't the same stuff a photo supplier will
sell you as "anti-newton glass", that's correct; the acid-etched "anti
glare" glass sold by frame shops is, as far as I can tell, the exact
same product, however.

But if you mean "coated glass doesn't _work_ as anti-newton glass",
you're not right. Newton's rings are an interference pattern; the
waves that are interfering are those reflected back and forth between
the surface of the negative and the surface of the glass. Coated glass
reduces the amplitude of each reflection from its surface by about 95%
compared to uncoated glass; so in fact it is a very effective way to
avoid Newton's rings.

Just for the benefit of my little brain, is that "coated glass" coated
with the same stuff used on lenses (magnesium fluoride, etc.)?


--
Pierre, mon ami. Jetez-vous une plus de Scientologiste
dans le vat de l'acide.

- from a posting in alt.religion.scientology titled
"France recommends dissolving Scientologists"

In article ,
David Nebenzahl wrote:

Just for the benefit of my little brain, is that "coated glass" coated
with the same stuff used on lenses (magnesium fluoride, etc.)?

I don't know. The coating process is different -- it's some kind of
dip process instead of the vacuum sputter used to deposit coatings on
lenses. The resulting coating isn't as durable but it is a lot cheaper
to do and still cuts reflections.

One manufacturer (Tru-Vue) supposedly uses a sputter process for
coating some of their framing glass but I don't know if this is really
the same process used to coat lenses nor what the benefits are, in
practice.

--
Thor Lancelot Simon

"We cannot usually in social life pursue a single value or a single moral
aim, untroubled by the need to compromise with others." - H.L.A. Hart