notes-on-optical-printer-technique/ocr/tesseract_output.txt

= NOTES ON OPTICAL PRINTER TECHNIQUE

Magnification 1 Fadea in Original 14
Blowup.& Reduotion 2 Chart C: Neutral Déneity and

Blowup Sharpness 2 Equivalent Shutter

Printer Lenses 3 Angle 15
Optical Zoom 3 Image Superposition 16
Lene Aperture 3 Gamma # Bipack 16
Focusing 4 Incidentally 16
Focusing Aperture 4 Exposure Compensation 18
Focusing Precision 4 Special Originals 18
Focusing Target 4 Texturing 18
Depth of Field 4 Multi-Exposure 19
Bolex Priam 4 Multi-Pack 19
Bolex Groundglass 4 Natural Superposition 19
Defecus 4 Flashing 19
X-Y Adjustment 4 Contrast Adjustment 19
Exact 13:1 5 Color Image Superposition 20
Ainframe 5 Weighted Double Exposures 20
Franelines 6 Dissolves 21
Emulsion Position T Effects Dissolves 2}
Time 8 Fades from Negative 21
Fancy Freeze 8 Color Exposure 22
Fancy Slow 8 Testing 22
Diffusers 8 CC Pack Reduction 25
UV Filter 9 High Contrast Printa 25
IR Filter 9 Hicon Exposure 26
Green Filter 3 Contrast Building Steps 26
Filter Location 9 Hicon Speckle 26
Exposure 9 Tone Isolation 27
Exposure Adjusters 9 Logie of Mask Combination 27
Specifying Exposure 11 Image Spread and Bloom 27
Film Speed 11 Mask and Countermask 28
Right Exposure 1 Reversal/Negative Fitting 28
Generations 2 Feathered Maska 29
Bellows Formula 13 Image Marriage 2g
Fades 13 Mask Blacknesé 30
Log Fade 14 Hicona from Color Originals 30
Bolex Variable Shutter 14 Hicon Processing 30
Linear Fade 14 Optical Printed Release Prints 31
Other Fades 14 Ritual and Art 31

i on
| revisec .
NOTES ON OPTICAL PRINTER TECHNIQUE
DENNIS COUZIN
March 1983

An optical printer 18 a device for photographing the frames
of one film sco as to make another filn.

e 2 - . ,
I
Cc

It consists essentially of @ camera (C) connected by a
bellows (B) to a lens (L) aimed at a film in a gate (G) illuminated
from behind by a lamp (I).

The camera and gate each have motorized intermittant filin
movements so that any frame of the "original" film can be
conveniently photographed onto any frame of the "print" filo.

The camera can be an ordinary cine camera, less its lens,
and the gate can be an ordinary cine projector, less its lens.
Ideally they have identical syatemsa of film registration, aa if
one Were the lens’ image of the other. The lens can be any
bellows mountable lens. Ideally it ie specially corrected for
the amall and nearly equal sizes of this object and image.

The camera and the lens can elide independently to and fro
the film gate. Thie adjustea the magnification and the focus of
the photography.

MAGNIFICATION If the lens is (nominally) midway between the films

when one is focused on the other, then the magnification
is 1. At M=1 (also called 1:1} the whole of the original
frame 1s photographed at a size which fllis the whole
of the print frame.

i ) oY ?
If the lens 18 moved closer to the gate, then the
camera must be moved back, farther from the gate,

_ to keep the one film focused on the other. Then the
Copyright (1983 by Dennie Couzin

r
2
magnification is greater than 1. At M>1 a part of the
original frame is photographed at a size which fille the
whole of the print frame.
If, starting from the 1:1! setup, the lene is moved
farther from the gate, then the camera must also be
moved back, farther from the gate, to keep the one film
focused on the other. Then the magnification is loser
than 1. At M<1! the whole of the original frame is
photographed at a size wohich does not fill the whole
of the print frame. The remainder of the print frane
46 filled with a photograph of the gate as it surrounds
the original frame (ideslly perfectly black).
6 y
For each position of the lens there is exactly one
correct (focused) position for the camera. But for
each position of the camera (except the 13:1 position)
there are two correct positions for the lens. One
gives M>1, the other M<}.
BLOWUP & REDUCTION The printer gate may hold Smm film and the printer
camera 16mm, or vice versa. With ap M=2 setup an
Sum original frame 18 photographed onto a whole
1énm frame. With an M=¢t setup a whole !6um original
frame is photographed onto an Smm frame. Conversion
between any two film gauges 4s possible thia way,
provided the frames have the sane proportions, as
Sum, super San, 16mm, and some 55ma do.
BLOWUP SHARPNESS A 16mm picture of a flea can be just as sharp ae
@ 16mm picture of an elephant. Fut & \é6an picture
of an Smm picture cannot be expected to be as sharp
as a t6mn picture of a 16mm picture. Pictures differ
. from thinge in having very limited detail. The 16as
blawup, even if it preserven all the pictorial detail
of the mm original, spreads it out, so the blowup
ie less sharp absolutely than the original.

,
3

Under extreme magnification -- a microscope objec
eould be the printer lene -- pictorial detail i: diffuse
and the underlying natural thing, the enulsion, is all
that could be photographed sharply. But the grains are
too small to be sharply imaged with light. Here even
the natural thing haa been photographically exhausted,
an 8mm original blown up to 16mm and projected will
appear sharper than the sane 8mm original optically
printed onto Smm and projected. If the blowup optics
are good thie is even true when the 1:1 printing is by
contact. Likewise for 16mm to 35mm. (This ie all due
to the print film being in effect twice as sharp and
half as grainy in a bigger frame.)

PRINTER LENSES A lens well-corrected for M-1 is less well-corrected

for M=? (or M=t). A lene Wwell-corrected for M=2 is
leas wall-corrected for M=4 (or M=%). Etc. (Floating
elementea improve this.) A lens well-corrected for M=1
for a larger format is lees than ideal for M-1 for a
smaller format. With such specialization (and expense)
in optical printer optics what ie the hope for the

$50 SOmm enlarger lens, optimized for M=.1 and much too
large a format? Wot bac, provided the sharpest aperture
ie found and heeded and focusing technique is eine.
Aleo, for Mé! ano asyunetrical lens should be mounted
the right way, which is usually with its smaller glass
facing the smaller image.

A very sharp cheap printer lens is the Canon Macrophoto
35mm £/2.8.

OPTICAL ZOOM Optical printers do not use soom lenses, although they could.
An optical printer toom is made by moving the camera and
lene each frame, so as to vary magnification while holding
focus. It is a dolly shot! A dolly abot is equivalent
to a toom for a flat subject.

Geometrically this zoom oan be identical to a zoom had

it been made in the original photography. It can also

be deviant, by tracking not to the center of the frame.
Pictorially the zoom gets grainy, showing that it was

not made in the original photography.

Rather than focua at each frame, camera am lene positions
can be precharted for, say, every 10th frame, and the other
positions interpolated or computed. On the J-E, counting
the turns of the lead screw ie a means of repeatable
positioning. A follo¥-focus sechanian is @ boon to optical
Z£oons.

The rate and course of s00ming is a factor of style,

as it is in original cinematography.

LESS APERTURE” For picture taking the printer lens should be at whichever
aperture gives the sharpest pictures. This 4e found in
teste. If a lens must be atopped down past f/8 to reach
optimum it is a terrible printer lene.

F
4
FOCUSING Printer focusing procedure is different at different magnifi
At 1:1 the camera, not the lens, 4e moved for focusing,’ Gulp)
at magnifications greater than about 1.4 18 it better to nove
the lens for focusing.
Near the t:1 setup lens motion has no focusing effect. With
the camera fixed in its 1:1 position lens motion: adjusts
magnification between about M=.96 and M=1.04 (at f/5.6).
FOCUSING APERTURE With all but the best optical printer lenses either
(1) foous at the taking aperture or (2) foous at a
larger aperture and then shift focus by a pre-established
distance before taking. This "fudge-factor" is found in
film teate.
FOCUSING PRECISION Especially when focusing stopped dowm, focus many
times (perhaps 20) and set an average position.

FOCUSING TARGET Use whatever target ie found eablest to focus on.
One caution: the fudge-factor is target dependent.
Very fine resolution targete may require different
fudge factora than coarser targete do.

DEPTH OF FIELD at indicated f/5.6 there is already more than enough
depth of field for a4 bipack, at 1:1. dAleo it ig unnecessary
to refocus when adding the second film. Likewlee when
a single film ie reversed’ emulsion to base. At larger
apertures and at larger magnifications depth of field
is lese.

BOLEX PRISM It isn't a worry. There len't a distinetion between RX

lenees and non-RX lenses for most any lens which will be
used on a bellows for optical printing.
BOLEX GROUNDGLASS Only for the best optical printer lenses, which will
be used at apertures larger than f/4, does the Bolex
groundglass need to be reset from its everyday position.
DEFOCUS To throw an image out of focua without changing ite size, if
printing at i:1, move the camera 4 distance and the lens ¢ this
dietance, in the same direction.

X-Y ADJUSTMENT Besides its to and fro movement the lene haa lateral
movements. These adjust the position of the original
frame's image on the print frame. For example, if the
lens is raised a bit...

5
At 1:1 moving the lens up a distance d raises the viewed
field by twice 4d. Likewise for down, right, and left.
At M>1 lateral adjustment effects a scan of the original
frame. This is not geometrically equivalent to a pan,
bad it been made in the original photography,
On simple optical printers the only lateral ad Justment
is of the lens (rather than the heavier camera or gate).
Thie is Geometrically adequate.
But the J-K adjustments are even too flimsy for a lens.
It helps, after they are set, to gently tap the lens, ac
it finds a stable position, and then to readjust if
necessary, etc., etc.

EXACT 1:1 The lateral movements of the lens, the to-fro movements of

the lens and camera, and a tilting of the camera (if necessary)
allow the optical printer to be set for exact 1:1 reproduction.
Then the printed image is the same aize and in the same position
as the original image. If the printer lacks a tilt adjustment
the oamera may be shinmed.

AIMFRAME A Special frame is made to guide the exact 1:1 setup. To make
an "aimframe" use the optical printer camera (though not
necessarily with the optical printer lens) to photograph a
target which is epecially drawn to contain detaila exactly’
coinciding, as seen through the camera eyepiece, with details
permanently on the groundglass. The photograph made while the
coincidence is seen is the ainfrane.

Every groundglass has some permanent detaile, even if only ite
flaws. The field edge is a poor choice of detail if the mask
is thick or if the eyepiece is aberrated at the edge. Two
points of detail are enough for a well~aligned printer, three
pointe for a suspect one.
A reticle made on high resolution film may be attached to the
groundglass to add details. Small patterns of concentric circles
and other patterns which self-moiré are ideal. also the ainframe
can be a negative of the fine-patterned reticle.
For exact 1:1! setup, the aimframe film is registered in the
printer gate and the printer camera and lens adjusted to
achieve that same coincidence of details, as seen through
the eyepiece. Focusing must be completed before the final
adjustment to the aimframe. It is convenient to incorporate
a focusing target in the aimframe.
The aimframe has validity only for the camera in which it was
made. It does not depend on the accuracy of the camera'a
reflex viewing eystem, only the stability of the eysten.
Whenever there is doubt about the validity of the aimfrane,
such as after a camera repair or because of wear to the filn,
the old aimframe can be registered in the printer gate, aimed
on, .and photographed to make a newly valid aimframe.

For rotoscoping with primitive contrapLions, an aimframe may
be projected and drawn. This drawing is later used to aim
the camera (whose aimframe it was) when photographing the
rotoscoped drawings.

Fo
6
The 1:1 accuracy of optical printing with aimframe setups ie
limited by 1. the precision in the making and then in the use
of the aimnfraze,
2. the precision in the film registration mechanians
of camera and gate,
3. only if the two mechanieme are different, the
precision in the film dimensions (perforation
and alitting).
Btep contact printing, Buch 48 by bipacking in the optical printer
eamera, if & convenient method for making exact 1:1 reproductions.
It must give exposures which are exact 1:1, but there 18 then sone
shrinkage in processing. Optical printing with the ainfrane methoc
compensates for processing shrinkage. Shrinkage errore are too
apall to matter with simple printers.

GAMEFRAME A atrip of identical frames, shot in the optical printer camera,
is cut in two and registered in both the printer gate (upright,
eanulgion away from lene) and the camera gate (ae it was shot).

The coincidence of detaile of image and sameframe is viewed throug
an opening in the rear of a special pressure plate. <A prismatic
gate focuser may be pubstituted for the pressure plate, but only
the most positive registration systems will be unaffected by this.
Only the most solid optical printers will allow loading the carers
without diesturblog thé setup.
The sameframe method does not compensate for processing shrinkage.
FRAMELINES If the camera which made the original film had a frameline

much higher or lower than that of the printer camera, then

the vertical adjustment of the lene should deviate from the

aimframe setup, to compensate for thia. Otherwise the print

will have a very thick, or even 4 double frameline.

Sometimes the sole reason for optical printing is to ad juat

the height of the frameline of an original fim shot with

a Wayward camera. Sometimes it is to simulate such filo.

Then the printer camera must have ite frameline adjusted.

For a Bolex thie is a simple claw exchange (revertible).

To make a frameline adjustzent, 4f the reflex viewfinder is

well-set, then even if it does not view the full frame, the

vertical adjustment can be made until the upper framelins

just appears, then until the lower frageline just appears,

and the two adjustments averaged.

If the reflex viewfinder is untrustworthy, then a camera

gate focuser can be used. Or thia method: register in ye

printer gate a bipack of the original with any file ahot in

the printer camera. Determine how much vertical adjuetaent

separates their framelines. Make that puch adjustment to

the aimfrane setup.

The framelines of the original can always be eliminated

from the print by setting the magnification slightly greater

than 1..

7
EMULSION POSITION A priori, a film of an alphabet could be any of these
eight ways.
F lh
F Sc G
¢||e FE
F F
Ia Ib IIa IIb
—__ —— ls
4 4 5 2
12) |
o 4 a
IIIa IIIb IVa IVb .
Each sketch showa emulsion facing out. For doubie
perf film there are only four ways. The a and b ways
become the sane.
Camera original is IIIa. *
A contact print from camera original is Ib.
A contact print from a contact print from canera
original is IIIa again. Etc.
All the othere are shams ~-- either optical printing
errors or elae films of alphabets somehow reversed.
Given a double perforated I, II, III, or IV it is easy
to make a double perforated optical print whioh ia
any of the four.
Single perforated filme are a pain in the side. Given,
for example, IIIa, it ia possible with a usual optical
printer to make either Ib, IIb, IIIa, or IVa, but none
of the other four. These could be made via a double
perforated intermediate. With a priem or other image
rotator, or a special reversed gate, it ie possible
to convert any of the eight ways to any of the elght ways
Figuring out how to do these is a good exercise for
the student.
The two non-sham emulsion positione are aketched again,
thie time with emulelona facing 1n shown dotted.
a O-— a o—4
- re o-— F
oS G G 6
oOo ats o—— on
CAMERA ORIGINAL CONTACT PRINT FROM
. CAMERA ORIGINAL
- Notice that when pietmres "read right" single perfs are
, on the left, and “before” .is above.
Notice that camera original reads right with emulsion
facing away. Contact print of camera original reads
right with emulsion facing toward the viewer.

8
Except when optical printing is done in alliance with
contact printing, it is usual to maintain emulsion
position through ali optical printing etepa. Atarting
with camera original each generation ie again IIIa.
For this there is a simple rule.
To reproduce the emulsion position of the original,
insert it in the printer gate with emulsion away
from lene, heads up, running upward.
Optical printing "through the base" does not degrade
image quality.
The optical printer can also imitate the contact printer,
if the original is inserted in the printer gate with
enulsion toward the lens.
TIME The optical printer gives as absolute oontrol over the flow or fits
of time as the gods could have. But it's just a movie.

Actually, two limitations on optical printer’time manipulation are

the grainy ground of film pictures and the mere 24 frames per second,

as show by these two examples.

FANCY FREEZE A single frame of the original printed repeatedly is a
freaze frame. Unfortunately the running graiu pattern
of the original freezes with the picture. The picture
has lost its ground. This can be avoided if there are
at least three frames without motion in the original, by
alternately printing among the three.

FANCY SLOW To slow motion to 3/4 speed (as is required when original
shot at 182pe is to be made into a 24fps print) it is usual
to print every third frame twice. ABCDEFGHI... becomes
ABCCDEFFGHII... . The micro-freezes, juat two frames long,

. coming every 1/6 second, are perceived through their rhythn.
This oan be avoided by randomizing the frames to be doubled
while still ohoosing one frame from each three of the original.

DIFFUSERS For poorly designed condenser systems a diffuser will even

the illumination over the frame.
Other than for this, diffusers are located immediately
behind the original film to alter image quality in several
ways:
1. reduce the appearance of scratches on the film base;
2. soften the appearance of grain, and without reducing
resolution per se, reduce sharpness;
3. reduce the apparent oontrast of B&W originals,
approximating the tonality in contact printing.
Opal glass, a more extreme diffuser than groundglaasa, is
more effective in each of the three Ways.
An opal glase oan reiuce exposure by 4 or even more stops.
An accidental or for;otten opal glass can devastate an exposure!

9
UV FILTER 4 filter which absorbs the ultraviolet, such as Wratten 25
or 2E improves sharpness with almost all lenses.
Also, printing oolor film onto color film, or BEéW film onto
color film, there is color reproduction advantage to using
a UV filter.
Some color rawstooks have such filtration built in, some don't,
Even printing color film onto B&W film there is tonal advantage
to using a UV filter.
IR FILTER A filter which absorbs (or reflects) the infrared keeps much
of the light energy which would heat the original but not
contribute to the photography, off the original. Thia filter
must be located between the lamp and the original.
Printing Kodachrome original onto color film, there is color
reproduction advantage to using a filter which reflects the
far red (past 670nm) and near infrared. Printing other color
originals there is color reproduction disadvantage to using
a filter (such as many heat filters) which remove the far red.
GREEN FILTER Printing B&W to B&W with a nOn-apochromatic lena, a green
filter can improve sharpness.
FILTER LOCATION The spectral effect of a filter on the photography is
the same wherever it ia looated between the lamp and
the rawatock. The optical effect of a filter can't be
good, #o it ought to be located on the illumination side
of the original rather than on the image-formation side.
(There, flawe in filters are harmless. A color filter
may even be perforated to reduce its effective saturation. }
EXPOSURE In optical printing as in original photography, the expoaure ig
adjustable, and a necessary consideration. But there is a
differenoe. The natural scene may exhibit an immenes brightness
range, from the brightest light sources (and secondary sources --
reflections) to the darkest light sinks. The film original
4s limited in brightness rangs, between the clear of the base
and the maximum density of the amulsion. This could be an
11 atop range for some color reversal fllms, but only about
6 atops for a negative original.
The exposure problem in original photography is to decide what
portion of the immense brightness range to capture on the filn.
The exposure problem in optical printing is to decide how to
capture on the print film the whole of the original image range.
EXPOSURE ADJUSTERS SHUTTER SPEED 4 variable speed motor or gearing can
give a few atops of adjustment. Brevity is limited by
inertia. <A single-frame mechaniem cannot be expected to
complete a cycle in less than about .! second. Slow
running ie unlimited, but emulsions miarespond to very
~ long exposures, losing sepeed and gaining contrast.

10
With the variable shutter the shutter speed (the time
the light etrikes a point in the frame) may be adjusted
although the printer camera runs at just one speed.
Exposure can be adjusted over eeveral stops with the
variable shutter. Brevity 16 limited by the ehutter
mechanics which must give equal even exposures at the
smallest shutter angles.
To cut exposure by 1 etop using the Variable shutter,
halve the shutter angle. To cut another stop, halve
it again.
Uaing the variable shutter for exposure adjustment makes
4te use for fades or dissolves inconvenient.
LENS APERTURE This is a Billy way to adjust exposure.
Changing lene aperture changes picture sharpness.
Except for fine expoeure adjustments (t# stop) the
lens ia beet left at ite sharpest opening.
(For exposure testing and other dirty work, lens
aperture 1a a handy exposure adjuster.)
LAMP VOLTAGE This ie the classical way to adjust
exposure for B&W printing. But it introducee eolor
changee. Also, modern halogen lamps lose life at
prolonged low voltages. Voltage adjustment is a
practical means for fine exposure ad juetment.
Dropping the voltage 10% reduces the light about t
stop while changing the color about CCOSY¥+CCOecM.
POLARIZERS Two polarizere, one rotatable, i8 a cute
way to adjust exposure. But sheet polarizere get
hot and have short lives in the optical printer.
Only very expensive ones can maintain color neutrality
i over a 10 stop adjustment range, and it is ead to
fry then.
ND FILTERS These grey filtere are the preferred
way to adjust exposure.
.30 of Neutral Density equala one etop.
Neutral Density values add as filters are stacked.
Thus an ND.10 filter + an ND.20 filter + an ND. 50
filter works like an ND.60 filter, and thie cuts
the light 2 atope. Etc.
.10 of Neutral Density equals 1/3 stop.
A clear glase or film may be ueed ae an ND.035 filter
E for finer exposure ad justmente.
Long, graded ND filters allow econtinuove expoaure
adjustment.

ND filters of higher value become hotter and have
ehorter lives. In a pack of ND filters, lower values
should go toward the lamp. Past .60 it makea little
difference.
Wratten #96 gelatin ND filtere are expensive because
of their optical quality, unnecessary Where they are
located in the optical printer.
Lee theatrical filters #209, #210, and #211 are good
for ND.30, ND.60, and ND.90 and cost 1/100 as much as
Wrattene.
There are glass ND's, both absorptive and reflective,
of great permanence. Also, developed B&W filmes, fine
halftone screens, etc. can be used as ND filters.
SPECIFYING EXPOSURE The many variables of exposure include:
1. the type of original filn and ita pictorial qualitie
2. the type of print film (and if a lab stock its
batch number)
3. magnification
4, lena aperture
5. diffuser (if any)
6. lamp voltage
7. shutter angle
8. non-ND filtration
as well as 9. ND filters
FILM SPEED ABA and related values are specialized to original picture
taking and are not quite appropriate to optical printer
applications. The values are informative for comparison
of similar atocks. For many printing filme 4SA and related
values are undefinable.
The optical printer will have exposure standards unto itself,
determined by testing. Once it is known how to beat expose
, a certain original onto a certain print film, good estimates
can be made for similar originals or similar print films.
RIGHT EXPOSURE Working in revereal there 18 a temptation to want the
optical print to match the original. Resist this
temptation! You want the optical print that produces
the best release print.
(Even if the optical print must be intercut with the
original, so that the two must produce matching release
print, it doeen't follow that the two must match, and
they shouldn't.)
Starting from reversal camera original the beet reversal
. optical print ie typically a littie (about ND.20) Garker
than the original. This avoids the print film's toe.
, The best reversal optical print of thie will mateh it.
And so on.

t2
Starting from negative camera Original the best interpositiy
print has some density in the highlighte. The beat
internegative ts a little darker than the origtnal négative.
A further interpositive would best match the firat one, etc.
GENERATIONS Gammas multiply. For example, @ gamma 1,5 Original printed
onto gamma 2 etock resemblea a ganna 3 original,
in @tany-generation pictorial Optical printing a chain of
B400e 1 a@tene results in unchanging picture contrast.
393 and CRI are gamma | color reversal stocks. 7243 18 a
Fanma ? color negative atock. PXR and 7361 are ganna 1 B&W
revergal etocka. 7235 16 a gamma t Baw negative stock.
For B&W negative there is the option of alternating gamnas
above and below 1 -- 7366 with gamma 1.4 and 7234 with Fanme
-? -- and multiply out to 1.
There are no available reversal stocks with Gamma less than 1,
For color reversal ECO, until ite disappearance in 1985, was a
favorite gamma 1! camera stock and ECO--ECO--ECO--atc. was the
classical printing scheme. ECO--7399--7399--stc. was A eimilar,
possibly better echeme. For each, only the release print would
be on higher gamma stock. No present color reversal scheme has
that advantage. Higher gamma original VEF-=-7399-=-7399--etc,
18 a printing scheme. For this, the release print too will be
on 7399. Original Kodachrome follows the VHF achene.
7399 stock misbehavea with exposure times longer than about
-1 second.
For B&eW reversal PXR--PXR--PXR--ete. is the classical printing
Scheme. PXR--7361--7361--eate. 4a a Similar, slightly better
scheme. For each, unless an Cpal @iffuser ia used the effective
gamma is much greater than t.
For color negative ECN--7243--7243--ete. is the classical
printing acheme. The alternating positive and necative pictures
allow different manipulations. Optical printing from picture
negative requires unusual cleanliness, to avoid white apecke
in the final image. A food atratery La to make the odd printing
atepa quick and simple, perhape even contact printed.
The shortcut acheme for eolor negative ECN--CRI--CRI--ete.
comprises only picture negatives.
For B&W negative there ia a shortcut schene BWN--7361--7361--ete
Tonal degradation sometimes confused with contrast increase
may be due to misexposure, or to impossible exposure (as when
the print film lacks the exposure range to handle the denaity
range of the Original). Then picture falls on toe or shoulder
; and ia tonally compressed.

13
Through generations graininess semi-adds. The grain of the
original is in part added to the grain of the print stock.
The print may thue look leas grainy than the original, or
more grainy, or juet differently grainy.
Through generations sharpness diminishes. The unsharpnegs of
the original joins the unsharpneas of the lens and the unsharp-
nesa of the print stock, in the print. Sharpnesa may be
boosted, however, by boosting contrast.
Optical printing with the best lenses onto relatively thick
emulsion print films may be sharper than contact printing.
Generally optical printing isn't as sharp.
Picture degradation from generation to generation could be
avoided by making the pictures very large, or by digitalizing
them. But in thie medium the original, intermediate, and
final pictures are all of the same eize, made in similar ways,
of similar materials. Besides the practical economy, there
ia conceptual economy in this. Intuitions transfer easily
from one formally similar picture phase to another. Thus
Making the generations the same makes them different. This
is the paradox, or the folly, of optical printing.

BELLOWS FORMULA Exposure way change with magnification. A "bellowa
forgula" works for moet printer lenses and most 1illuminatio:
systema. It prescribes...

magnification compensation
M=.13 add ND.50
M=.18 add ND. 46
M=.25 add ND. 41
M=,35 add ND.34
M=.50 add ND.25
M=.71 add ND.14
M=1 normal
‘ _ remove ND.16
er i M= remove ND.35
Binsup Sper i -# N=2.8 remove ND.56
M=4 rencve ND.S80
M=5.7 remove ND1.04
u-8 remove ND1.31
FADES Pictures like things fade in many ways. Brightness fades are
Gradual exposure changes leading to black, or, starting from black
leading to normal exposure.

o fade out with a positive original, exposure is decreased, either
ty adding ND filtera to the normal pack or by closing the shutter,.
some more each frame. When the ND added is somewhat darker than
the black of the original, this counts as exposure cutoff.

|
14
To fade out with a negative original, with the same effect,
exposure is increased, by subtracting ND filtere from the normal
pack, some more each frame. When the ND subtracted ia somewhat
darker than the black of the original, thia counts as exposure
cutoff. Thia fade is imposaible without an abundant reserve of
printer illumination. The normal pack must contain enough ND for
the removal. 4n alternative is discussed below after dissolves.
& fadein i6 the simple reverse of a fadecut.
LOG FADE The traditional fade ia made from a positive and ta logarithmic.
With ND fliters a log fadeout is made by adding each new frame
a ocertain amount more ND. With revereal orlginal, 5.00 added
about completes the fadeocut. For example, a 350 frame log
fadeout ie made by adding .10 of ND each frame.
For every ND value there is an equivalent shutter angle. Chart
C below shows the equivalences and ia adaptable to any shutter,
A Variable shutter could be callibrated in both degrees and
ND's. But toward the bottom of Chart C the angular settings
are too close for ordinary wariable shutters. Long smooth
log fades from reversal original are difficult with variable
ehutters. However, from interpositive original a fade ia
finished at about ND1.60, avoiding the difficulty.
BOLEX VARIABLE SHUTTER Although it is marked in stops, it is configured
for angular callibration. Open is 130°. Just
closed is 0°, Midway is 65°, Percentage of
full can be substituted for degreea. Fine
ecallibration should not be attempted for there
is play in the mechanisaa.
LINSAR FADE The linear fadeout, compared with the log fadeout of the
sane length, starts slower and finishes faster.
With a variable shutter a linear fadeout from a positive
original 16 made by subtracting each new frame a certain
angles. For aimplicity, take a jinear fadeout to be conplete
at O°. For example, with a 180” shutter a 30 frame linear
fade changes 6° each frame.
ND filters can be used to make a linear fade. The fade
is planned as if for a variable shutter and then ND
equivalents are found in Chart C.

OTHER FADES any gradual transition between full exposure and black
4s an exposure fade. The "look", and perhaps the "meaning",
of a fade depends on how the expoeure changes with the frames.

FaDES IN ORIGINAL A fade made fron a scene looks distinctly different

from one made from a film image of the scene if the
scene containge bright highlights. Made from the acene,
the highlights shine on when the remainger of the scene

~ is practically black. Made from the film, the highlighte
follow the other light parte of the picture.

sak] C NEUTRAL DENSITY AND EQUIVALENT SHUTTER ANGLE i
PERCENT DEGREES DEGREES
NEUTRAL OF FULL FOR 170° FOR °
DENSITY SHUTTER SHUTTER SHUTTER
0.00 100% 170°
205 89.1% 152°
«10 79.4% 135° ae
-15 70.8% 120° =
~20 63.1% 1079 oo
225 56.2% 96° —==
30 50.1¢ 95°
235 44.7% 76° <==
»40 39.8% 68° —
45 35.5% 60° Sell
50 31.6% 54°
~55 28.2% 48°
60 25, 1% 43°
-65 22,48 38°
-70 20.0% 34° ___
75 17,84 30° ae
.80 15, 8% 27°
~85 14.1% 24°
90 12.6% 21,40
-95 11.2% 19,19 =
1.00 10.0% 17.09
1.05 8.91% 15.2°
1.10 7.94% 13.59 aa
1.15 7.052 12.0° =
1.20 6.31% 10.7
1.25 5.62% 9.6°
1.30 5.01% 8.59 =a
1.35 447% 7-60 aaa
1.40 3.98% 6.8
1.45 3.55% 6.0° — an
1.50 3.16% 5.40
1.55 2, 52% 4,89 _
1.60 2.51% 4,30
1.65 2.24% 3.80
1.70 2.00% 3.45
1.75 1.78% 3.0 _ a
1.80 1.58% 2.7° ss
1.85 1.41% 2,4°
1.90 1.26% 2.149 _
1.95 1.12% 1.91° ____
2.00 1.00% 70° [==
2.05 891% 1.52° ____
2.10 ~ 794% 1.359
2.15 . 708% 1, 20°
2.20 .6312 1.079
2.25 562% .96° ____.
2.30 501% 2 Ee
2.35 AATE 76 ____
2.40 3985 68° o——— 7
2.45 -355% -60° —————
2.50 3162 «540 ———F
2.55 . 2828 48° ——s
“ 2.60 251% 43° —=
2.65 2248 38 a
2.70 . 200% . 34°
2.75 .178% 30° _—
2,80 158% . 27° =
2.85 141% . 24° Sica

a
i **Refer to this chart when slanning linear fades and tissolveg++
Equivalent Shutter Ovenines
+N. % of Full Shutter 190° 130° Tz=7
00 100 180 130 25
05: 89.1 140 115 209
.10 79.4 143 193 15¢
215 70.8 127 92 15e
~ .20 *3.1 114 82 148
225 54,2 101 73 132
-.30 (1 stop) 50.1 90 65 117
—.35 44,7 80 53 195
—.40°' 39,8 72 52 94°
~.45 35.5 Ad 46 33
~ 2 50: - 31.6 57 41 74
-.55 28,2 51 37 Ae
~ .60-- (2 stops) 25.1 45 33 5a
~ 45 22,4 40 29 53
~.70 ° 20 36 26 A7
~.75 17,8 32 23 42
“.80-: 15.8 29 20 37
™~,BS 14.1 25 18 33
(2 FR > ™~.90 (3 stops) 12.6 23 1A 30
~.95 11.2 20.2 15 26
™ 4,00: - 10 18 13 24
ee ™1.05 8.91 16 12 21
ad 1.10: - 7.94 14.2 19 19 |
1.15 7.08 12.7 2 17 |
.  ™“1.20.-(4 stops) 6,31 11.4 3 15
1.25 5.62 10.1 7 13
~. ™1.30° 5.01 9 7 12
13s 4,47 B 2 11
“1. 40 3.98 7.2 G 9
™ 1,45. *~ 3.55 6.4 5 3 5
1.50 (5 stops) 3.15 5.7 4 7 .
~~
2:00

16

IMAGE SUPERPOSITION In an overall combination of two images, the two

can infuse each other as lightness or as darkness,

or they can be slapped onto each other. There are

three basic types of image superposition, named

according to how they are made.

Pictures A & B combined by...

(1) Double exposure from positives. The print film
is eared twice, once from A's positive, once
from B's positive.

(2) Double exposure fron mepetizes: The print film
Ts expose wice, once from A 8 negative, once
from B's negative.

(3) Bipack. Two films, either A's and B's positives,
Or é6lee A's and B's negatives, are inserted
together in the printer gate. The print film
4s exposed once, from this pair.

The print film is unspecified. It is in the final

positive print that the three types of combination

are compared, and they look very different. For

B&W the differences can be described by how tones

combine.

With (t}, lightness dominates. Where one tone

combines with another tone the result is nearly

the lighter of the two tones.

With (2), darkness dominates. The result ia nearly

the darker of the two tones.

———=> With (3), there is contrastification which complicates
the tone combination. If a bipack is examined ray
(unprinted) wherever both images are clear the bipaer
4a clear. Wherever either image is black the bipack
4s at least that black. Wherever both images are
black the bipack is doubly black. The bipack, whiob
appears dark, has a tonal range doubling that of the
single images. The bipack is wprintable in toto.

To abstract a pioture from the unprintable bipack

printing exposure is typically increased 1-4 atops.

With 4 stops increase, where clear and black eoincide

printe as a dark grey would—not 4 clear domination

of either lightness or darkness. With 2 stops increase

there is darkness domination.

GaMMa ¢ BIPACK If the bipack is printed onto gamma $ material, to reduce
the contrast to normal, it is a true tonal blender,
without dowinance, of the two images. As the graphs below
show, the gamma # bipack ia the mean between the type (1)

~ and type (2) double exposures.

INCIDENTALLY A type (3) of a type (1) and a type (2) le just a type (3)

again.

r. a a
17

Four idealized graphs summarize the three basic types of

superposition and the gamma # bipack.

Example: 4 has density .75 and B has denaity 1.75 in one
place. From the first graph, the double exposure
from positives has density about 1.0 in that place.

as Pous exfosup am Foss as BiPACK. (10 Come

as Me de

is ib fo]

je ia

cy -

e

5 = io LS ts a: Sg = he Lf wt as

Ly Ltt L Pi 5 A ‘a 2 2 APPA L elie

= i wat

ae Le

‘ly \ WX |

Fo x7 14 ie to as 85 e 2 4 20 oe

For a double exposure it doesn’t matter which exposure is

first, or what time separates the two. In some multi-head

optical printers, using 4 bean-splitter, the two exposures
are simultaneous. Kither way, the two filma can be
independently adjusted for exposure, filtered, etc.

For a bipack it doesn't matter which film ie in front. Also

the two may be optically instead of mechanically bipacked.

In some multi-head optical printers the films are in separate

~gates, ones projection becoming the other's illumination. Ir

a simple printer one film may be in the gate and the other in

the camera, in front of the print film. Any Way, the two

films ehare one exposure adjustment and filtration.

18
When filmwe will be physically bipacked they should firet
be wiped with a lubricating film cleaner. This ie good
practice for all optical printing when delicate originals
receive heavy handling.

EXPOSURE COMPENSATION For superpositions from random pictorial originale:
For double exposures, the typical exposure adjustment
is one stop of decrease from normal, during each
exposure.

With this adjustment a double exposure of
picture A with picture A ie the Bame as a
single normal exposure of A.
For bipacks there ie no recipe. Expoaure adjustment
ie extremely dependent on whioh tones coincide with
which. The adjustment is an increase from normal.
In ignorance of the originals (why?) and ignorance
of the intentions (why?) guess 2% stops increase.
No exposure adjustment can make a bipack of
picture A with picture A the same as picture
A printed the same. But a gamma $ bipack of
picture A with picture A is the same a6 picture .
SPECIAL ORIGINALS For superpositions not from random pictorial originals
tones might not combine at all. One image might fall
on the other's black, or clear, and exposure compensation
48 different, perhaps unnecessary.
With special, rigged, originale superposition is not
image combination in the earlier sense but image
apportionment -- implantings and supplantings.
The rulee of tone combination etill apply, but trivially,
and a eimpler logic prevails.
Double exposing from positives, where one image is
——_>> black the other image appears, unaffected by the doubie
exposure, Where one image is very light it appears,
hardly affected by the double exposure.
Double exposing from negatives, where one image (the
picture, not the film) ie clear the other image appears,
unaffected by the double exposure.
Bipacking, where one image is any even tone, the other
image appears, unaffected exoept for brightness. The
clear parts of one film are windowa for the other film.
But it is possible, with enough extra exposure, to
force one image through the blackened window of the other
The most extreme cases of rigged originals involve high
contrast masks, Gisoussed below.
TEXTURING In~a bipack, an image.of a plain white eurface, showing just
= ite texture, imparte this texture to the other image.

19

MULTI-EXPOBURE Triple, quadruple, etc. multiple exposures are made

similarly to double exposures. If there would be 5
exposurea from the same or nearly the same original,

then each should receive 1/5 normal exposure. From

Chart C, 1/5 of full shutter equals ND.70 compensation.

eat lizely the originals are special, and the compensation
ess,

MULTI-PAck Tripacks, quadripacks, etc. are unmanageable in simple optical

printers. For suob effects intermediate prints must be made.
For example, to quadripack A,B,0,D make printed bipacks of

A with B and C with Dand bipack these two printe. The order
of the originals doesn't matter.

NATURAL SUPERPOSITION Of the three types only (1), the double exposure
from positives, corresponds to possible camera origina:
4n original double exposure made from two real scenes
la practically the same as a printer double exposure
made from positive images of the acenes.

Type (2), the double exposure from negatives, ia

an artifact of the "log linear" response of negative
films.

Type (3), the bipack, is an artifact of the
transparency of film images, at least one of then.
Type (1) 16 nature's super. Preasing one eyeball
produces such superpositions.

FLASHING Double exposing an image with no image -- sere light -- lightens
(or with colored light and color print filma, colors) the blacks
and darker tones while having little effect on middle tones
and even lese on lights. It is8 not a true method of contrast
reduction.

Sepia toning can be simulated by both color flashing and color
filtering when printing B&W original onto color reversal print filr
A healthy yellow, magenta, or cyan flash when printing onto color
reversal film yields, respectively, the yellow, magenta, or cyan ~
image, as if this dye layer were prised from the original film.
There ie no photographic method for unflashing a flashed image.
There is image addition (double exposure} and image pultipliocation
(Dipack) and even image division (bipack of positive with
negative), but no image subtraction.

CONTRAST ADJUSTMENT Gammas add or subtract in a bipack, so bipacking

can adjust contrast. A bipack (printed gamma 1 or
Viewed raw) of an original with its duplicate is
like a double contrast original. <A bipack of an
original with its low contrast negative is like

~ a darkened reduced contrast original.
“fhe bipack of an original with ite high contrast
negative is like a Sabattier solarization!

20
COLOR IMAGE SUPERPOSITION There are the same three basic types.
Double exposure from positives gives additive
color mixture.
Bipacking gives so-called subtractive color
mixture. Uwnen bipacking color negatives the
extra orange mask should be neutralized by
filtering.)
Double exposure from negatives gives something
else.
For greys in the two images, combination 1s
as for B&W. But for colors, not only are new
colors produced but apparent brightnesses do
not combine quite the same ae for B&W.
The dyea in Wratten CC filters Y,H,C are
aimilar to those in color filma. Film colora
can be simulated by packs of these filters and
much can be learned about film color manipulation
from familiarity with the filters and their
combinations.
Exapple 1: Image & is orange (CC200Y+CC100M)
Image B ts blue (CCtO00M+CC200C)
Double exposure from poaitives gives a raspberry
color (CC7OM+4ND. 30)
Double exposure from negatives givee a fairly dark
greyish green (CC7OY+CC70C4ND1.00)
Bipack, with 3 stop exposure compensation, gives a
middie grey (ND1t.10)
Example 2: Image A is maximum red (CC250Y+CC250M)
Image B is maximum green (CC250Y+CC250C)
Double exposure from positives gives yellow (CC220Y+ND.5
Double exposure from negatives givee black (CC30Y+ND2. 20
Bipack, with 3 stop exposure compensation, gives
brown (CC9OY+NDt.60)
Example 3: Image A is a flesh (CC30Y+CC20M+CC10C)
Image B ia sky (CC6OM+CC80C)
Double exposure from positives gives Neola yecckeeoosec)
Double exposure from negatives gives cc18y+CC45M+Cc58C
Bipack, with 1 stop exposure compensation, gives
( CCSOM+CC60C)
WEIGHTED DOUBLE EXPOSURES In double and other multiple exposures there is
~ no need to have the several exposures equal. To
plan Weighted multi-exposures, work in shutter
angles allotted to each original. Typically the
total will be full shutter. Shutter angles can
be converted to ND's using Chart C.

DISSOLVES A diesolve begins with one picture. Then a second picture
gradually appears, all over the frame, shares the frame with
the firat picture, and gradually replaces it.

The traditional dissolve i8 a simultaneous (double exposed)

linear fadeout of the firat image and linear fadein of the

second, made from positive images.

A simultaneous log fadeout and log fadein makes quite a lumpy

dissolve (becoming dark midway, from positive images).

Regular dissolves are planned as if for variable shuttere. At

each frame the ahutter angles for the two exposures must sun

to the full shutter angle. ND equivalents can be found in

Chart C and ND filters can be used to make the dlasolve.

It 18 not necessary for the fadeout and the fadein to be the

same or even of the same type. <Any chosen fadeout has a

complementary fadein (found by subtractions from full shutter

angle), and vice veraa.

A diseolve from negative originals is made by pretending they

are positives and following the method for positives. No

dissolve made from negative originale will look the same as

a dissolve made from the corresponding positive originals.

EFFECTS DISSOLVES Diseolves are great emoothers, not only between scenes

but between "“effecta".
For example, a dissolve between a picture illuminated
through one color filter and the same (synchronized)
picture illuminated through another color filter makes
a slur of colorations -- a straight line course through
color space -- between the two.
A dissolve between a picture positive and the same
(synchronized) picture negative forma a pictorial
bridge from positive to negative. The bridge ia of
strange stuff. The all-grey picture is not on the way.
The mentioned strange atuff is reminiscent of Sabattier
solarization again. The double exposure of a picture
with its negative, preferably onto contrasty filo,
gives a reversing tonality: Dark things become lighter
than middle tone things, which remain darker than light
things.

FADES FROM NEGATIVE If a diasolve ie made between a negative original

and a clear {or orange) film the result resembles

a fadeout. For the fadeocut to resemble a log fadeout
a special dissolve ta required. The clear film ia
faded in approximately logarithmically, and the
negative is faded out couplementarily.

22
COLOR EXPOSURE The earlier discussione of exposure apply as well to
color printing except that now color and brightness are
adjustable. The adjustments are made primarily with
cco filters and ND filitere.
A CCY-- filter worke roughly like an ND.-- filter on
just the blue part of the spectrum, while not affecting
the rest of the epectrum. Similarly a CCM filter cuts
the green and a CCC filter cute the red. ND filters
could be eliminated by CC filters. For example, ND.30
4a roughly CC30Y+CC30M+CC30C. This elimination ie
seldom practical and slightly inferior spectrally.
Color adjustments are made secondarily with UV filters,
IR filters, and band rejection filters.
As with B&W, correction of misexposed originals ehould
be done in earlier rather than later printing stepa-
TESTING For a general color exposure determination, the test original
should be a well-exposed film of the relevant kind, preferably
with large areas of pear-neutral mid-tones.-
Jointly varying cC and ND filtration, a long series of test