Sprockets - Revision history

JesseCrooks: /* Sprocket Design By Film Gauge */ Added images of VKF and Posi-Trol sprockets.

2020-05-30T01:26:11Z

Sprocket Design By Film Gauge: Added images of VKF and Posi-Trol sprockets.

← Older revision		Revision as of 18:26, 29 May 2020
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	====LaVezzi Posi-Trol====		====LaVezzi Posi-Trol====
	After the use of CS perfs died out in the early 1980s, LaVezzi redesigned their VKF sprockets to only accommodate film with KS perforations. They recentered the sprocket teeth to align with KS perfs and widened the teeth on one side to fill more of the width of the perforation. This “positive control” resulted in increased horizontal stability. However, these sprockets cannot be used with CS perfs, and can present issues with shrunken KS perfs. As a result, they are not recommended for archival projection.		After the use of CS perfs died out in the early 1980s, LaVezzi redesigned their VKF sprockets to only accommodate film with KS perforations. They recentered the sprocket teeth to align with KS perfs and widened the teeth on one side to fill more of the width of the perforation. This “positive control” resulted in increased horizontal stability. However, these sprockets cannot be used with CS perfs, and can present issues with shrunken KS perfs. As a result, they are not recommended for archival projection.

			<gallery widths=150px heights=150px mode=packed>
			File:CS and VKF sprocket teeth.png\|A comparison of CS and VKF sprocket teeth, shown within a CS perf (black) and KS perf (white).
			File:Posi-Trol sprocket teeth.png\|Posi-Trol sprocket teeth, shown within KS perfs.
			</gallery>

	===16mm===		===16mm===

JesseCrooks at 03:01, 28 May 2020

2020-05-28T03:01:42Z

← Older revision		Revision as of 20:01, 27 May 2020
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	[[File:KS as CS sprockets (standing).JPG\|right\|thumb\|~~300px~~]]		[[File:KS as CS sprockets (standing).JPG\|right\|thumb\|400px]]

	Sprockets are toothed drums that engage with the [[perforations]] (also called '''sprocket holes''') to advance the film through the projector.		Sprockets are toothed drums that engage with the [[perforations]] (also called '''sprocket holes''') to advance the film through the projector.
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	===Dual-Gauge===		===Dual-Gauge===
	[[File:Century JJ Intermittent.JPG\|right\|thumb\|~~300px~~\|The dual-gauge intermittent sprocket on a Century JJ, attached to the intermittent mechanism.]]		[[File:Century JJ Intermittent.JPG\|right\|thumb\|400px\|The dual-gauge intermittent sprocket on a Century JJ, attached to the intermittent mechanism.]]

	Sprockets designed for [[dual-gauge projectors]] have two sets of teeth. Teeth for the larger gauge are located on the outside edge of the sprocket, while teeth for the smaller gauge are recessed in the center of the sprocket at a smaller diameter. The difference in diameter allows the film to be transported at the correct speed without adjusting the projector’s drive speed. For example, the combined intermittent sprocket for a 35/70 projector will advance 35mm film by four perforations per step while 70mm film is advanced five perforations per step.		Sprockets designed for [[dual-gauge projectors]] have two sets of teeth. Teeth for the larger gauge are located on the outside edge of the sprocket, while teeth for the smaller gauge are recessed in the center of the sprocket at a smaller diameter. The difference in diameter allows the film to be transported at the correct speed without adjusting the projector’s drive speed. For example, the combined intermittent sprocket for a 35/70 projector will advance 35mm film by four perforations per step while 70mm film is advanced five perforations per step.

JesseCrooks: /* 35mm */

2020-05-28T03:00:05Z

35mm

← Older revision		Revision as of 20:00, 27 May 2020
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	==Sprocket Design By Film Gauge==		==Sprocket Design By Film Gauge==
	===35mm===		===35mm===
	~~[[File:KS and CS sprockets (teeth close-up).jpeg\|right\|thumb\|300px\|Sprockets with Kodak Standard teeth (left) and CinemaScope teeth (right).]]~~
	====Kodak Standard (KS)====		====Kodak Standard (KS)====
	The early standard for 35mm projection, designed for use with KS perforations. The teeth are centered on the KS perforation, and are larger than the teeth found on later sprockets. Any projector still in regular operation is unlikely to have KS sprockets, as they would have been replaced with CinemaScope (CS) sprockets in the 1950s.		The early standard for 35mm projection, designed for use with KS perforations. The teeth are centered on the KS perforation, and are larger than the teeth found on later sprockets. Any projector still in regular operation is unlikely to have KS sprockets, as they would have been replaced with CinemaScope (CS) sprockets in the 1950s.
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	====CinemaScope (CS)====		====CinemaScope (CS)====
	A sprocket designed for use with early CinemaScope prints, which had narrower perforations to make room for a 4-track magnetic soundtrack. Even theaters that did not upgrade their equipment to run magnetic sound were still incentivized to switch to CS sprockets because dual-format MagOptical prints were provided to theaters without mag readers. Beginning with the introduction of CinemaScope in 1953, CS sprockets eventually became the new standard. Because sprockets wear down after years of service, KS sprockets were eventually replaced with CS sprockets on older machines.		A sprocket designed for use with early CinemaScope prints, which had narrower perforations to make room for a 4-track magnetic soundtrack. Even theaters that did not upgrade their equipment to run magnetic sound were still incentivized to switch to CS sprockets because dual-format MagOptical prints were provided to theaters without mag readers. Beginning with the introduction of CinemaScope in 1953, CS sprockets eventually became the new standard. Because sprockets wear down after years of service, KS sprockets were eventually replaced with CS sprockets on older machines.

			<gallery widths=300px heights=300px mode=packed>
			File:KS and CS sprockets (teeth close-up).jpeg\|Sprockets with Kodak Standard teeth (left) and CinemaScope teeth (right).
			File:MagOptical.png\|A MagOptical CinemaScope print with CS perfs.
			File:LaVieEnRose frames.png\|A modern CinemaScope print with KS perfs.
			</gallery>

	====LaVezzi VKF====		====LaVezzi VKF====

JesseCrooks at 02:45, 28 May 2020

2020-05-28T02:45:42Z

@@ Line 1: / Line 1: @@
-* Different types, examples
+[[File:KS as CS sprockets (standing).JPG|right|thumb|300px]]
-See also: [[perforations]]
+Sprockets are toothed drums that engage with the [[perforations]] (also called '''sprocket holes''') to advance the film through the projector.
 [[Category:Projector components]]

Rfhall: Created page with "* Different types, examples See also: perforations Category:Projector components"

2013-08-01T21:40:11Z

Created page with "* Different types, examples See also: perforations Category:Projector components"

New page

* Different types, examples

See also: [[perforations]]

[[Category:Projector components]]