Added more sections but still in progress. Committing work without compiling new pdf

NOTES_ON_OPTICAL_PRINTER_TECHNIQUE.md

@@ -840,3 +840,97 @@ 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.
+
+## EXPOSURE COMPENSATION
+
+For superpositions from random pictorial originals:
+
+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 same as a single normal exposure of A.
+
+For bipacks there is no recipe.
+Exposure adjustment is extremely dependent on which 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 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.
+
+## 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.
+
+With special, rigged, originale superposition is not image combination in the earlier sense but image apportionment--implantings and supplantings.
+
+The rules of tone combination still apply, but trivially, and a simpler logic prevails.
+Double exposing from positives, where one image is black the other image appears, unaffected by the double 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) is clear the other image appears, unaffected by the double exposure.
+
+Bipacking, where one image is any even tone, the other image appears, unaffected except for brightness.
+The clear parts of one film are windows 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, discussed below.
+
+## TEXTURING
+
+In a bipack, an image.of a plain white eurface, showing just its texture, imparts this texture to the other image.
+
+## MULTI-EXPOSURE
+
+Triple, quadruple, etc. multiple exposures are made similarly to double exposures.
+If there would be 5 exposures 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.
+More likely the originals are special, and the compensation less.
+
+## MULTI-PACK
+
+Tripacks, quadripacks, etc. are unmanageable in simple optical printers. 
+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.
+
+## NATURAL SUPERPOSITION 
+
+Of the three types only (1), the double exposure from positives, corresponds to possible camera original.
+An original double exposure made from two real scenes is practically the same as a printer double exposure made from positive images of the scenes.
+
+Type (2), the double exposure from negatives, is 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 them.
+
+Type (1) is nature's super.
+Pressing 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!