Enlarging plates
Automatic
focusing system
Focus
variator
14
pin
is
located on the
left-
and right-hand sides
to
adjust the opening
distance
between
the upper and
lower
sections
of
the
negative carrier.
If
the
enlarger
is equipped
with
lenses
of
28
and
50
mm.,
the
DUONEG
negative
carrier
is
delivered
as
standard
equipment
and
that
complete
with
the
DUMA
masks
for
the
following
negative
formats:
12
x
17
mm.
(1/2x11/16")
Rolle'i,
3f4x1"
(18x24
mm.l.
P/
lI
;"
sq.
(26x26
mm.)
and
35
mm. (24 x
36
mm.).
To
enlarge
1314
x
2%"
(4.5 x 6 cm.) and
2V2
x
3112"
(6.5 x 9 cm.)
plates
the
specially
designed URAN
plate
holder
is available as a separate
accessory. The
format
inserts
of
this
holder
allow
the
enlargement
even
of
wet
plate negatives. The negative plane
of
the
URAN plate
holder can be adjusted
to
the focusing plane
of
the automatic focus-
ing
system
so
that
the
plate
holder
may also be used
with
the
automatic
focusing
system.
To
match up
the
focusing planes
of
the
plate holder
and
of
the
automatic
focusing
system,
project
a
test
negative upon
the
projection
board,
at
best
with
the
enlarger head in
its
uppermost
po-
sition.
If
the
test
negative appears unsharp,
adjust
the
height
of
the
plate
holder
by
turning
its
knurled focusing ring (a)
either
to
the
left
or
to
the
right.
This
is
then locked
with
the
screw
(b) and
the
URAN
plate holder
is
adjusted once
for
all.
a
URAN
The
DURST
DA
900
focuses
automatically
with
the
lenses
which
have
been adjusted
at
the
factory. The movable lens carriage (33)
must
be locked in
the
exact
position,
otherwise
the automatic focusing
system does
not
function.
The lenses are changed
by
grasping
the
pushing - bar (26) and never
by
grasping
the
lens
tubes
themselves.
The
lenses are adjusted
to
their
utmost
sharpness
of
focus. For
this
reason, do
not
loosen
the
screws
of
the
lens boards (12)
or
of
the
lenses
themselves.
If
you
desire
to
move
the
focusing
plane
to
a
point
higher
than
the
plane
of
the
projection
board,
it
is
possible
to
raise the focusing
plane up
to
10
cm.
(4")
by means
of
the
focus
variator
wheel-grips
(34). This is necessary
when
the
enlarging paper
(for
instance,
whqe
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