16mm
/
notes-on-optical-printer-technique
1
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

Add hyperlinks to sections from the index page.

This commit is contained in:
Matt McWilliams 2022-07-31 19:58:24 -04:00
parent e22eaa3515
commit d444d47cc3
2 changed files with 149 additions and 42 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

191
NOTES_ON_OPTICAL_PRINTER_TECHNIQUE.md
View File

@ -10,45 +10,45 @@ date: "March 1983"
| | | | |
|-----|-----|-----|-----|
| Magnification | 1 | Fades in Original | 14 |
| Blowup & Reduction | 2 | Chart C: Neutral Density | |
| Blowup Sharpness | 2 | and Equivalent Shutter | |
| Printer Lenses | 3 | Angle | 15 |
| Optical Zoom | 3 | Image Superposition | 16 |
| Lens 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 Prism | 4 | Multi-Pack | 19 |
| Bolex Groundglass | 4 | Natural Superposition | 19 |
| Defocus | 4 | Flashing | 19 |
| X-Y Adjustment | 4 | Contrast Adjustment | 19 |
| Exact 1:1 | 5 | Color Image Superposition | 20 |
| Aimframe | 5 | Weighted Double Exposures | 20 |
| Framelines | 6 | Dissolves | 21 |
| Emulsion Position | 7 | Effects Dissolves | 21 |
| 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 Prints | 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 | Logic of Mask Combination | 27 |
| Specifying Exposure | 11 | Image Spread and Bloom | 27 |
| Film Speed | 11 | Mask and Countermask | 28 |
| Right Exposure | 11 | Reversal/Negative Fitting | 28 |
| Generations | 12 | Feathered Masks | 29 |
| Bellows Formula | 13 | Image Marriage | 29 |
| Fades | 13 | Mask Blackness | 30 |
| Log Fade | 14 | Hicons 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 |
| [Magnification](#magnification) | 1 | [Fades in Original](#fades-in-original) | 14 |
| [Blowup & Reduction](#blowup-and-reduction) | 2 | [Chart C: Neutral Density](#chart-c) | |
| [Blowup Sharpness](#blowup-sharpness) | 2 | [and Equivalent Shutter](#chart-c) | |
| [Printer Lenses](#printer-lenses) | 3 | [Angle](#chart-c) | 15 |
| [Optical Zoom](#optical-zoom) | 3 | [Image Superposition](#image-superposition) | 16 |
| [Lens Aperture](#lens-aperature) | 3 | [Gamma & Bipack](#gamma-and-bipack) | 16 |
| [Focusing](#focusing) | 4 | [Incidentally](#incidentally) | 16 |
| [Focusing Aperture](#focusing-aperature) | 4 | [Exposure Compensation](#exposure-compensation) | 18 |
| [Focusing Precision](#focusing-reprision) | 4 | [Special Originals](#special-originals) | 18 |
| [Focusing Target](#focusing-target) | 4 | [Texturing](#texturing) | 18 |
| [Depth of Field](#depth-of-field) | 4 | [Multi-Exposure](#multi-exposure) | 19 |
| [Bolex Prism](#bolex-prism) | 4 | [Multi-Pack](#multi-pack) | 19 |
| [Bolex Groundglass](#bolex-groundglass) | 4 | [Natural Superposition](#natural-superposition) | 19 |
| [Defocus](#defocus) | 4 | [Flashing](#flashing) | 19 |
| [X-Y Adjustment](#x-y-adjustment) | 4 | [Contrast Adjustment](#contrast-adjustment) | 19 |
| [Exact 1:1](#exact-1-1) | 5 | [Color Image Superposition](#color-image-superposition) | 20 |
| [Aimframe](#aimframe) | 5 | [Weighted Double Exposures](#weighted-double-exposures) | 20 |
| [Framelines](#framelines) | 6 | [Dissolves](#dissolves) | 21 |
| [Emulsion Position](#emulsion-position) | 7 | [Effects Dissolves](#effects-dissolves) | 21 |
| [Time](#time) | 8 | [Fades from Negative](#fades-from-negative) | 21 |
| [Fancy Freeze](#fancy-freeze) | 8 | [Color Exposure](#color-exposure) | 22 |
| [Fancy Slow](#fancy-slow) | 8 | [Testing](#testing) | 22 |
| [Diffusers](#diffusers) | 8 | [CC Pack Reduction](#cc-pack-reduction) | 25 |
| [UV Filter](#uv-filter) | 9 | [High Contrast Prints](#high-contrast-prints) | 25 |
| [IR Filter](#ir-filter) | 9 | [Hicon Exposure](#hicon-exposure) | 26 |
| [Green Filter](#green-filter) | 3 | [Contrast Building Steps](#contrast-building-steps) | 26 |
| [Filter Location](#filter-location) | 9 | [Hicon Speckle](#hicon-speckle) | 26 |
| [Exposure](#exposure) | 9 | [Tone Isolation](#tone-isolation) | 27 |
| [Exposure Adjusters](#exposure-adjusters) | 9 | [Logic of Mask Combination](#logic-of-mask-combination) | 27 |
| [Specifying Exposure](#specifying-exposure) | 11 | [Image Spread and Bloom](#image-spread-and-bloom) | 27 |
| [Film Speed](#film-speed) | 11 | [Mask and Countermask](#mask-and-countermask) | 28 |
| [Right Exposure](#right-exposure) | 11 | [Reversal/Negative Fitting](#reversal-negative-fitting) | 28 |
| [Generations](#generations) | 12 | [Feathered Masks](#feathered-masks) | 29 |
| [Bellows Formula](#bellows-formula) | 13 | [Image Marriage](#image-marriage) | 29 |
| [Fades](#fades) | 13 | [Mask Blackness](#mask-blackness) | 30 |
| [Log Fade](#log-fade) | 14 | [Hicons from Color Originals](#hicons-from-color-originals) | 30 |
| [Bolex Variable Shutter](#bolex-variable-shutter) | 14 | [Hicon Processing](#hicon-processing) | 30 |
| [Linear Fade](#linear-fade) | 14 | [Optical Printed Release Prints](#optical-printed-release-prints) | 31 |
| [Other Fades](#other-fades) | 14 | [Ritual and Art](#ritual-and-art) | 31 |
:::
\newpage
@ -80,7 +80,9 @@ Ideally it is specially corrected for the small and nearly equal sizes of this o
The camera and the lens can slide independently to and fro the film gate.
This adjusted the magnification and the focus of the photography.
## Magnification
<a name="magnification"></a>
## 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 is photographed at a size which fills the whole of the print frame.
@ -103,6 +105,8 @@ The remainder of the print frame is filled with a photograph of the gate as it s
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 1:1 position) there are two correct positions for the lens. One gives `M > 1`, the other `M < 1`.
<a name="blowup-and-reduction"></a>
## BLOWUP & REDUCTION
The printer gate may hold 8mm film and the printer camera 16mm, or vice versa.
@ -110,6 +114,8 @@ With a `M = 2` setup an 8mm original frame is photographed onto a whole 16mm fra
With an `M = 1/2` setup a whole 16mm original frame is photographed onto an 8mm frame.
Conversion between any two film gauges is possible this way, provided the frames have the sane proportions, as 8mm, super 8mm, 16mm, and some 35mm do.
<a name="blowup-sharpness"></a>
## BLOWUP SHARPNESS
A 16mm picture of a flea can be just as sharp as a 16mm picture of an elephant.
@ -127,6 +133,8 @@ If the blowup optics are good this is even true when the 1:1 printing is by cont
Likewise for 16mm to 35mm.
(This is all due to the print film being in effect twice as sharp and half as grainy in a bigger frame.)
<a name="printer-lenses"></a>
## PRINTER LENSES
A lens well-corrected for `M = 1` is less well-corrected for `M = 2` (or `M = 1/2`).
@ -141,6 +149,8 @@ Also, for `M != 1` an asymmetrical lens should be mounted the right way, which i
A very sharp cheap printer lens is the Canon Macrophoto 35mm f/2.8.
<a name="optical-zoom"></a>
## OPTICAL ZOOM
Optical printers do not use zoom lenses, although they could.
@ -160,12 +170,16 @@ A follow-focus mechanism is a boon to optical zooms.
The rate and course of zooming is a factor of style, as it is in original cinematography.
<a name="lens-aperature"></a>
## LENS APERTURE
For picture taking the printer lens should be at whichever aperture gives the sharpest pictures.
This is found in tests.
If a lens must be stopped down past f/8 to reach optimum it is a terrible printer lens.
<a name="focusing"></a>
## FOCUSING
Printer focusing procedure is different at different magnification.
@ -174,21 +188,29 @@ Only at magnifications greater than about 1.4 is it better to move the lens for
Near the 1:1 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).
<a name="focusing-aperature"></a>
## FOCUSING APERTURE
With all but the best optical printer lenses either (1) focus at the taking aperture or (2) focus at a larger aperture and then shift focus by a pre-established distance before taking.
This "fudge-factor" is found in film tests.
<a name="focusing-precision"></a>
## FOCUSING PRECISION
Especially when focusing stopped down, focus many times (perhaps 20) and set an average position.
<a name="focusing-target"></a>
## FOCUSING TARGET
Use whatever target is found easiest to focus on.
One caution: the fudge-factor is target dependent.
Very fine resolution targets may require different fudge factors than coarser targets do.
<a name="depth-of-field"></a>
## DEPTH OF FIELD
At indicated f/5.6 there is already more than enough depth of field for a bipack, at 1:1.
@ -196,19 +218,27 @@ Also it is unnecessary to refocus when adding the second film.
Likewise when a single film is reversed emulsion to base.
At larger apertures and at larger magnifications depth of field is less.
<a name="bolex-prism"></a>
## BOLEX PRISM
It isn't a worry.
There isn't a distinction between RX lenses and non-RX lenses for most any lens which will be used on a bellows for optical printing.
<a name="bolex-groundglass"></a>
## 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.
<a name="defocus"></a>
## DEFOCUS
To throw an image out of focus without changing its size, if printing at 1:1, move the camera a distance and the lens 1/2 this distance, in the same direction.
<a name="x-y-adjustment"></a>
## X-Y ADJUSTMENT
Besides its to and fro movement the lens has lateral movements.
@ -229,12 +259,16 @@ This 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, so it finds a stable position, and then to readjust if necessary, etc., etc.
<a name="exact-1-1"></a>
## 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 size and in the same position as the original image.
If the printer lacks a tilt adjustment the camera may be shimmed.
<a name="aimframe"></a>
## AIMFRAME
A special frame is made to guide the exact 1:1 setup.
@ -275,6 +309,8 @@ shrinkage in processing.
Optical printing with the aimframe method compensates for processing shrinkage.
Shrinkage errors are too small to matter with simple printers.
<a name="sameframe"></a>
## SAMEFRAME
A strip of identical frames, shot in the optical printer camera, is cut in two and registered in both the printer gate (upright, emulsion away from lens) and the camera gate (as it was shot).
@ -283,6 +319,8 @@ A prismatic gate focuser may be substituted for the pressure plate, but only the
Only the most solid optical printers will allow loading the camera without disturbing the setup.
The sameframe method does not compensate for processing shrinkage.
<a name="framelines"></a>
## FRAMELINES
If the camera which made the original film had a frameline
@ -304,6 +342,8 @@ Make that puch adjustment to the aimframe setup.
The framelines of the original can always be eliminated from the print by setting the magnification slightly greater than 1.
<a name="emulsion-position"></a>
## EMULSION POSITION
A priori, a film of an alphabet could be any of these eight ways.
@ -350,6 +390,7 @@ 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 emulsion toward the lens.
<a name="time"></a>
## TIME
@ -358,12 +399,16 @@ 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 shown by these two examples.
<a name="fancy-freeze"></a>
## FANCY FREEZE
A single frame of the original printed repeatedly is a freeze frame. Unfortunately the running grain 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.
<a name="fancy-slow"></a>
## FANCY SLOW
To slow motion to 3/4 speed (as is required when original shot at 18fps is to be made into a 24fps print) it is usual to print every third frame twice.
@ -371,6 +416,8 @@ ABCDEFGHI... becomes ABCCDEFFGHII... .
The micro-freezes, just two frames long, coming every 1/6 second, are perceived through their rhythm.
This can be avoided by randomizing the frames to be doubled while still choosing one frame from each three of the original.
<a name="diffusers"></a>
## DIFFUSERS
For poorly designed condenser systems a diffuser will even the illumination over the frame.
@ -384,6 +431,8 @@ Opal glass, a more extreme diffuser than groundglass, is more effective in each
An opal glase oan reduce exposure by 4 or even more stops.
An accidental or for;otten opal glass can devastate an exposure!
<a name="uv-filter"></a>
## UV FILTER
A filter which absorbs the ultraviolet, such as Wratten 2B or 2E improves sharpness with almost all lenses.
@ -394,6 +443,8 @@ 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.
<a name="ir-filter"></a>
## 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.
@ -402,16 +453,22 @@ This 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.
<a name="green-filter"></a>
## GREEN FILTER
Printing B&W to B&W with a non-apochromatic lens, a green filter can improve sharpness.
<a name="filter-location"></a>
## FILTER LOCATION
The spectral effect of a filter on the photography is the same wherever it is located between the lamp and the rawatock.
The optical effect of a filter can't be good, so it ought to be located on the illumination side of the original rather than on the image-formation side.
(There, flaws in filters are harmless. A color filter may even be perforated to reduce its effective saturation.)
<a name="exposure"></a>
## EXPOSURE
In optical printing as in original photography, the exposure is adjustable, and a necessary consideration.
@ -423,6 +480,8 @@ This could be an 11 atop range for some color reversal films, but only about 6 s
The exposure problem in original photography is to decide what portion of the immense brightness range to capture on the film.
The exposure problem in optical printing is to decide how to capture on the print film the whole of the original image range.
<a name="exposure-adjusters"></a>
## EXPOSURE ADJUSTERS
**SHUTTER SPEED** - A variable speed motor or gearing can give a few stops of adjustment. Brevity is limited by inertia.
@ -480,6 +539,8 @@ Lee theatrical filters #209, #210, and #211 are good for `ND.30`, `ND.60`, and `
There are glass ND's, both absorptive and reflective, of great permanence.
Also, developed B&W films, fine halftone screens, etc. can be used as ND filters.
<a name="specifying-exposure"></a>
## SPECIFYING EXPOSURE
The many variables of exposure include:
@ -494,6 +555,8 @@ The many variables of exposure include:
8. non-ND filtration (as well as)
9. ND filters
<a name="film-speed"></a>
## FILM SPEED
ASA and related values are specialized to original picture taking and are not quite appropriate to optical printer applications.
@ -503,6 +566,8 @@ For many printing films ASA 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.
<a name="right-exposure"></a>
## RIGHT EXPOSURE
Working in reversal there is a temptation to want the optical print to match the original.
@ -521,6 +586,8 @@ Starting from negative camera Original the best interpositive print has some den
The beat internegative is a little darker than the original negative.
A further interpositive would best match the first one, etc.
<a name="generations"></a>
## GENERATIONS
Gammas multiply.
@ -583,6 +650,8 @@ 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.
<a name="bellows-formula"></a>
## BELLOWS FORMULA
Exposure way change with magnification.
@ -605,6 +674,8 @@ It prescribes...
| `M = 5.7` |remove `ND1.04` |
| `M = 8` |remove `ND1.31` |
<a name="fades"></a>
## FADES
Pictures like things fade in many ways.
@ -622,6 +693,8 @@ An alternative is discussed below after dissolves.
A fadein is the simple reverse of a fadeout.
<a name="log-fade"></a>
## LOG FADE
The traditional fade is made from a positive and is logarithmic.
@ -638,6 +711,8 @@ But toward the bottom of Chart C the angular settings are too close for ordinary
Long smooth log fades from reversal original are difficult with variable shutters.
However, from interpositive original a fade is finished at about `ND1.60`, avoiding the difficulty.
<a name="bolex-variable-shutter"></a>
## BOLEX VARIABLE SHUTTER
Although it is marked in stops, it is configured for angular callibration.
@ -647,6 +722,8 @@ Midway is 65°.
Percentage of full can be substituted for degrees.
Fine callibration should not be attempted for there is play in the mechanism.
<a name="linear-fade"></a>
## LINEAR FADE
The linear fadeout, compared with the log fadeout of the sane length, starts slower and finishes faster.
@ -658,11 +735,15 @@ 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.
<a name="other-fades"></a>
## OTHER FADES
Any gradual transition between full exposure and black is an exposure fade.
The "look", and perhaps the "meaning", of a fade depends on how the exposure changes with the frames.
<a name="fades-in-original"></a>
## FADES IN ORIGINAL
A fade made from a scene looks distinctly different from one made from a film image of the scene if the scene containga bright highlights.
@ -671,6 +752,8 @@ Made from the film, the highlights follow the other light parts of the picture.
\newpage
<a name="chart-c"></a>
### NEUTRAL DENSITY AND EQUIVALENT SHUTTER ANGLE
CHART C
@ -778,6 +861,8 @@ CHART C
\newpage
<a name="image-superposition"></a>
## 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.
@ -811,11 +896,15 @@ To abstract a picture from the unprintable bipack printing exposure is typically
With 4 stops increase, where clear and black coincide prints as a dark grey would—-not a clear domination of either lightness or darkness.
With 2 stops increase there is darkness domination.
<a name="gamma-and-bipack"></a>
## GAMMA & BIPACK
If the bipack is printed onto gamma $ material, to reduce the contrast to normal, it is a true tonal blender, without dominance, of the two images.
As the graphs below show, the gamma 1/2 bipack is the mean between the type (1) and type (2) double exposures.
<a name="incidentally"></a>
## INCIDENTALLY
A type (3) of a type (1) and a type (2) is just a type (3) again.
@ -841,6 +930,8 @@ Any way, the two films ehare one exposure adjustment and filtration.
When films will be physically bipacked they should first be wiped with a lubricating film cleaner.
This is good practice for all optical printing when delicate originals receive heavy handling.
<a name="exposure-compensation"></a>
## EXPOSURE COMPENSATION
For superpositions from random pictorial originals:
@ -855,10 +946,12 @@ which.
The adjustment is an increase from normal.
In ignorance of the originals (why?) and ignorance of the intentions (why?) guess 2 1/2 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 1/2 bipack of
picture A with picture A is the same as picture.
> No exposure adjustment can make a bipack of picture A with picture A the same as picture. A printed the same. But a gamma 1/2 bipack of picture A with picture A is the same as picture.
<a name="special-originals"></a>
## 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 is different, perhaps unnecessary.
@ -876,10 +969,14 @@ But it is possible, with enough extra exposure, to force one image through the b
The most extreme cases of rigged originals involve high contrast masks, discussed below.
<a name="texturing"></a>
## TEXTURING
In a bipack, an image.of a plain white eurface, showing just its texture, imparts this texture to the other image.
<a name="multi-exposure"></a>
## MULTI-EXPOSURE
Triple, quadruple, etc. multiple exposures are made similarly to double exposures.
@ -887,6 +984,8 @@ If there would be 5 exposures from the same or nearly the same original, then ea
From Chart C, 1/5 of full shutter equals `ND.70` compensation.
More likely the originals are special, and the compensation less.
<a name="multi-pack"></a>
## MULTI-PACK
Tripacks, quadripacks, etc. are unmanageable in simple optical printers.
@ -894,6 +993,8 @@ For such effects intermediate prints must be made.
For example, to quadripack A,B,C,D make printed bipacks of A with B and C with D and bipack these two prints.
The order of the originals doesn't matter.
<a name="natural-superposition"></a>
## NATURAL SUPERPOSITION
Of the three types only (1), the double exposure from positives, corresponds to possible camera original.
@ -906,6 +1007,8 @@ Type (3), the bipack, is an artifact of the transparency of film images, at leas
Type (1) is nature's super.
Pressing one eyeball produces such superpositions.
<a name="flashing"></a>
## FLASHING
Double exposing an image with no image--mere light--lightens (or with colored light and color print films, colors) the blacks and darker tones while having little effect on middle tones and even less on lights.
@ -918,6 +1021,8 @@ A healthy yellow, magenta, or cyan flash when printing onto color reversal film
There is no photographic method for unflashing a flashed image.
There is image addition (double exposure) and image multiplication (bipack) and even image division (bipack of positive with negative), but no image subtraction.
<a name="contrast-adjustment"></a>
## 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.
@ -925,6 +1030,8 @@ A bipack of an original with its low contrast negative is like a darkened reduce
The bipack of an original with its high contrast negative is like a Sabattier solarization!
<a name="color-image-superposition"></a>
## COLOR IMAGE SUPERPOSITION
There are the same three basic types.

BIN
pdf/NOTES_ON_OPTICAL_PRINTER_TECHNIQUE.pdf
View File

Binary file not shown.