A
iil
i
2
tion is averaged over a certain area. In the low frequency range, where the line spacing
is of the same order of magnitude as the diameter of the “averaging area”, the dodging
is at its maximum. In the high frequency range, however, where the line spacing is con-
054
POSITIVE
DENSITY
H&D curve of contrasty paper
= rT High freq.
ic
for | f |
0 neq 0320 OW are | A... di tee Tf |
eee 11 En | low freq.
I I gradation
| I
| I
| low freq. | [
J dodging curve ——— |
= ;
y^ 4 I |
| treq. | ;
ow
Fi mi tuy i | | !
a v | | detail |
f ; oid l contrast !
Del I |
i p negative density renge i14
apparent | | | |
o mee d | | tr.
15 03
2 ! NEGATIVE. DENSITY 0
Relation between the Contrast Transfer Functions of dodging printers
and the modified H & D curve.
POSITIVE
DENSITY
Over ex-.
Starting points posure bt
9 diaz à ~~ over exposure
of dodging b ia > fos e NUS
---low freq. dodging curves
-—
-—
z"
_- proper exposure
(Not in scale)
ve, for backed dia-pos
-r
— proper exposure
Az for sw paper
proper exposure
for unbacked
dia - positives Sow
CT
_-~under exposure
ar
for backed dia-pos
NEGATIVE DENSITY RANGE
unbacked backed single weight double Ww. upper limit for contact
dia - pos. dia - pos. paper paper printing on various materials
with the same H & D curve
Fig.4. Influence of the transmittance of the positive material and influence
of under- and overexposure on:
the position of the low frequency dodging curve,
the reproduced negative density range (schematic).
siderabl
all.
Acc
negative
fluence,
decrease
increasii
caused
feedback
Wat pr
above a
printing
In a
fect giv
curve” a
the ideal
line.
Now
of the p
ciable in
foil is us
no light
printing
much be
of the m
the feedt
ing depe
negative
(in the
densities
light an
with inf
In th
Contrast
plotted o
Such
basic asy
4. The j
impor
with
that »
image
2. The f
MAX
aging
(Kel-(
tel).
The p
of cw
quenci
extent
4. The m
eo
