Cinematography-Theory-And-Practice

Figure 13.1. (previous page) CCE,a bleach-bypass process, is a criticalfactor in this image from Cityof Lost Children.COLOR PRINTINGNegative is printed either on a continuous contact printer or on astep printer. The step printer works somewhat like a projector inthat the movement is intermittent. Registration is achieved throughregister pins, which allows several passes to be made, as may be thecase with black-and-white separation negatives.Additive and Subtractive PrintingA printer must control the red, green, and blue components of thewhite-light source to achieve correct density and color balance. Twomethods of control are commonly used: additive and subtractiveprinting. In a subtractive printer, color balance is achieved by insertingcolor correcting filters in the light path between the light sourceand the printing aperture.Overall light density changes are made either by a variable apertureor a neutral density filter. Subtractive print involves using filterpacks and neutral density filters to make corrections. As a result, it isdifficult to make changes in setup. Subtractive printing is sometimesused for release prints, because there are no scene-to-scene colorchanges. Printing requiring any scene-to-scene color correctionsis not practical on a subtractive printer. The most common printingmethod is additive printing. In additive printing, there are threelight sources. These can then be combined in various percentages tocontrol both the density and color balance. The red, green, and bluecomponents are controlled with a set of dichroic mirrors.Printer LightsThe variations in each color channel are quantified on a scale from1 to 50. These are called printer points or printer lights. Increasing theprinter light by 12 printer points adds a stop of exposure. The standardprinter setup for a laboratory is usually 25-25-25 for the red,green, and blue color channel; some labs use different standards.In theory an 18% gray card perfectly exposed and processed willprint at 25-25-25. In actual practice this turns out to be only a generalguideline. Some labs use 30-30-30 as their aim density. Beyondthis, there are other minor variations due to differences in printeroptics and chemistry. This can be disconcerting, but in practice itis not important. Lab numbers are self-referential — they are usedwithin the same system at the same lab. Difference in one light causesdifference in .07 to .1 density, which is 1/6 to 1/7 of an f/stop; a 3light is 1/2 stop. Any deviations beyond this are of concern. If a labcannot print the same negative twice without half stop deviation,then there is clearly a problem.This standard can really only apply to answer prints and releaseprints, not to the dailies, which are the prints of a day’s shootingused to review and check for problems. Dailies are also called rushes.Essentially printer points are a closed system within each lab. Generally,most labs are within a couple of numbers of each other. However,there are other reasons why a lab may choose to set its referencepoint a little higher or lower than another one. Printing machineshave an overall line-up or offset known as the trim setting that isused to even out lamp, stock, filter, process, and other differencesbetween machines so that they produce the desired result.So prints from different labs can still look identical, even if theyhave different lights, because all the other factors are different aswell: its only the total combination of settings that matters. If youjudge your exposures by the rushes lights, you should ask the labwhat the normal lights are for the specific stock you’re shooting on.cinematography246