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'Printer lights' system for dummies please....


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Hi all, obviously, as a 'nobody' in this world my experience in motion picture film is simply that it's scanned once processed for me......in stills I shoot, process film and print myself in the darkroom if I want or else scan the negatives but I really dont know much about what the 'printer lights' system, can someone give us the definitive 'printer lights' for dummies guide in this thread complete with images or videos or whatever? Is it kind of like printing colour in the darkroom where you adjust the RGB 'filters' on the enlarger...for example, setting it at 70 yellow, 50 magenta and 0 cyan.

Edited by Stephen Perera
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19 minutes ago, Stephen Perera said:

? Is it kind of like printing colour in the darkroom where you adjust the RGB 'filters' on the enlarger...for example, setting it at 70 yellow, 50 magenta and 0 cyan.

Yes.

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...and this is when making the contact print to project right? so like colour grading before computers.....

Edited by Stephen Perera
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Yes, it’s the same thing as the RGB-filters on your enlarger.

But the device itself can a little bit more complex as the color correction/grading (via the filters) might have to be adapted scene by scene. (That is unless you choose „best light“ aka „one light“ aka „work print“.)

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The first shot-to-shot grading cues were Debrie clips- metal staples attached to the film just before the cut, detected by contacts on the printer. Later, the edge of the film was notched to activate a microswitch. By the 70s, the grader created a punch tape with the printer commands and the cueing was by frame count.

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22 minutes ago, Mark Dunn said:

The first shot-to-shot grading cues were Debrie clips- metal staples attached to the film just before the cut, detected by contacts on the printer. Later, the edge of the film was notched to activate a microswitch. By the 70s, the grader created a punch tape with the printer commands and the cueing was by frame count.

I have no idea nor can imagine anything of what you have just said hahaha...but I am sure its accurate and correct and I thank you for your message

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Printer lights are used in additive colour systems. The white light of a halogen lamp is split into red, green and blue channels, using mirrors and dichroic filters. In each channel there is a light valve, which is nothing more than a mechanically actuated diaphragm controlling the light output of each colour channel. here is a drawing by Brian Pritchard.

 

Bell & Howell Model C Lamphouse

The lights go from 0 to 50 with 0 being completely closed. During colour timing, the best value for each channel is determined.

25-25-25 is the middle setting, 31-31-31 would be printed one stop darker, 20-30-30 would be more red, etc.

 

 

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would be great if anyone have any more photos or whatever to add to this thread of perhaps stuff they have done themselves...thanks to everyone for the message much obliged

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If you search on "Bell & Howell Model C" a lot comes up.

brianpritchard.com

is also a good source. Brian is ex-Kodak. He may chip in here if he's still around.

Edited by Mark Dunn
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Memochrome is an additive RGB system for intermittent printers. It works with high-intensity LEDs, a control box, and an open Excel-based CSV data software. I have first used it in 2007. You have 50 points or steps for each light colour, freely programmable. One frame can get 25-25-25, the next 47-11-38, then 0-0-0, whatever. Limit is 32,000 sets. Maximum working speed is 25 frames per second.

The system is available in three variants, variable intensity, variable duration, variable distance. Print and intermediate film stocks react differently to increasingly short exposure, so variable duration is perhaps not everyone’s favourite, densities diminish exponentially with shorter flashes.

A glimpse at the innards of the prototype control box

Memochrome-SteuergertInneres.thumb.JPG.725cae6eb8088c782e3b7144376b6a82.JPG

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50 minutes ago, Stephen Perera said:

would be great if anyone have any more photos or whatever to add to this thread of perhaps stuff they have done themselves...thanks to everyone for the message much obliged

Our film lab network members have made some video tutorials for the Matipo:

https://vimeo.com/showcase/7866728

There are a lot of resources on film printing on the filmlabs website as well (but mostly in french):

https://www.filmlabs.org/technical-section/film-printing/

Edited by Gautam Valluri
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