Film-Tech Forum ARCHIVE: "contact printer"

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Posted by Steven J Hart (Member # 2340) on 08-14-2004, 07:54 AM:

Some prints have "contact printer" printed on the heads or tails. What does this mean?
Steve Hart

Posted by John Pytlak (Member # 331) on 08-14-2004, 09:50 AM:

A contact printer brings the printing negative and the raw stock into intimate CONTACT while wrapped around a 12-inch circumference sprocket, where light shines through the negative to expose the image on the print film:

http://www.kodak.com/US/en/motion/support/h1/printing.shtml

quote:
Continuous-Contact Printer. In its simplest form, printing consists of exposing the raw stock from an "original" or "printing master" to form the image using a light source to produce the exposure. When the image size of the print is the same as that of the original (i.e., 35 mm to 35 mm, 16 mm to 16 mm), the printing is usually done in a continuous-contact printer.

Posted by Gordon McLeod (Member # 33) on 08-14-2004, 10:44 AM:

this is a link to the Bell and Howell printer the standard base most are derived from
http://www.rtico.com/bhp/

Posted by Leo Enticknap (Member # 534) on 08-14-2004, 07:20 PM:

For info (Stephen - obviously this isn't news to John or Gordon), contact printing is one of two basic ways of copying a photographic image from one film to another. The other is 'optical' printing, in which the image of the source film is projected through a lens onto the destination raw stock in order to make the exposure.

Copying is always done using contact printing if possible, because by placing the source and destination elements in physical contact with each other, you'll get the best quality copy possible. With optical printing, the lens used to produce the image which exposes the raw stock will always introduce some distortion, however high quality that lens is. There are some cases, however, in which contact printing is impossible - for example if you need to copy one film gauge to another (e.g. blowing up 16mm to 35mm), introduce optical special effects or if an archive needs to copy a significantly shrunk original onto new, unshrunk duplicating stock.

Both contact and optical printers are further subdivided into two types: 'continuous' and 'step'. In a continuous printer, the source and destination films move constantly past an aperture or lens. A step printer has an intermittent mechanism, like a projector, and the duplicate is exposed frame by frame. Optical step printers are often used to photochemically copy archival elements which are in a very bad state indeed - usually severely shrunk or brittle.

It might be that digital intermediate processes will gradually reduce the need for optical duplication over time, and within a few years the only photochemical duplication which happens on any significant scale will be release printing using high-speed continuous contact printers. I recently sent a 1930s 16mm Dufaycolor film to a lab for enlargement to 35mm preservation elements and a print. We're having the preservation elements done photochemically, mainly because getting them scanned at 2k and a 35mm preservation negative output from there on a laser film recorder would be roughly twice the cost. I wouldn't be surprised if I place a similar order in a couple of years time, and find that the digital intermediate route is just as cheap, if not cheaper.

Posted by John Pytlak (Member # 331) on 08-16-2004, 09:24 AM:

Just a reminder that contact printers are designed to print a short pitch original (e.g., BH-1866 perfs) to a long pitch raw stock (e.g., KS-1870 perfs). If you print onto a short pitch raw stock, there can be slippage between the two films as they go around the 12-inch circumference printing sprocket, leading to some unsteadiness or sharpness loss.

Normal procedure should be to print the short pitch (BH-1866) cut negative to a long pitch (DH-1870) master positive on a wet gate contact printer. Then a pin-registered step printer is used to make the BH-1866 perfed duplicate negatives. Release prints are made using a continuous contact printer onto a long pitch (KS-1870) print stock.

Unfortunately, the short time lines in modern distribution sometimes force labs to use continuous contact printing for the critical master positive to duplicate negative stage, especially since multiple duplicate negatives are needed for a worldwide release.