Lubrication of Film to Protect It

[K Borowski]

I often lubricate home movies and anything I shoot on reversal to protect it from scratching during the editing phase. I am astounded to see scratches as so prevalent at the theatres I go to. Why exactly aren't at least the prints lubricated in movies? There's no archivability issues to deal with since prints get trashed after the theatres anyway, and a simple lubrication would increase print life exponentially. Any thoughts anyone?

 

Regards.

~Karl Borowski

[John Pytlak RIP]

Kodak has recommended that release prints be properly lubricated since the early 1920's. The Kodak ECP-2D processing specs and SMPTE Recommended Practice RP151 both specify that 35mm release prints be edgewaxed. However, the primary solvent (1,1,1-trichloroethane / methyl chloroform) that was used for this is no longer manufactured (it could deplete the ozone layer), and the other solvents are either flammable or more risky to handle.

 

There are proprietary film treatments (e.g., FilmGuard) that have become popular because they both lubricate and clean the print during showing. Even a bit of SCJohnson Paste Wax (a mix of carnauba and paraffin wax in naphtha) applied to the sidewall of the print will seep in along the edges and act as a lubricant. But care is needed not to apply too much.

[Dominic Case]

Lubrication can help prevent scratching: but there is no reason why the image area of a print should be rubbed over anything to scratch it anyway. Lubrication isn't the answer to visible scratches in the image area.

 

On the other hand, if excessive wax is applied to prints , then it stands a very good chance of building up on the runner plates in the gate area, and ultimately scratching the print - much, much more than if it had been left alone. This tends to result in damage to the perf area, and often to the digital track areas: and the resultant debris or flaking from the scratched-off emulsion appears as black sirt in the image area.

 

Scratches in the image area are usually a result of poor film handling, particularly when prints are being made up or broken down before and after the run (notice how it's always much worse at the end of reels?), or poor projector maintenance.

 

Some lubricants that have been used by poorly-informed projectionists (though not those recommended by Kodak such as Johnsons's floor-wax) actually destroy the emulsion dyes: so a light scratch that has damaged the protective supercoat will quickly fade the magenta dye and turn into a bright green line instead of a slightly less visible light black line.

[K Borowski]

I've always wondered what the green lines were. Thanks for your help John and Dominic. Are all prints lubricated by theatres then and not by the printer? Also, are all waxes going to cause fading. I use a silicone lubricant that hasn't given me any fading problems and is supposed to be similar to what Kodak used for home movies before they ceased lubricating them after processing, but I have heard that even procedures such as lacquering photographic prints (also recommended by Kodak until recently) can damage paper prints. Do either of you know what the archival characteristics of lubricants are?

 

Regards.

~Karl Borowski

[Dominic Case]

I've always wondered what the green lines were.

You will also, more usually, get green lines with a slightly deeper emulsion scratch, removing the top (magenta) dye layer. No wax or anything involved.

 

Are all prints lubricated by theatres then and not by the printer? 

Labs used to lubricate prints many many years ago, but for a while it was generally not found to be necessary (SMPTE & Kodak recommendations notwithstanding), and so it was discontinued by most. Some theatres have blanket instructions to lubricate everything within sight, others have an outright ban on lubricating prints.

 

Also, are all waxes going to cause fading.

Absolutely not. Depends on what the wax or the solvent is. A paraffin based wax (not oil) is recommended. Silicone seems to be OK too. Above all, avoid WD-40. (Don't laugh, it happens.)

[John Pytlak RIP]

The long standing Kodak recommendation of edgewaxing with hard waxes (carnauba, paraffin) disolved in a fast-evaporating solvent leaves only inert wax on the print. Applied properly by the lab, edgewaxing is a proven lubricant with a long history of successful use. Oily lubricants can leach out dyes or cause oil mottle, as Dominic points out. Silicones have been successful in some applications, but can make a print too slippery, may cause mottle, and have a tendency to migrate. Continuous loop cartridges (used for Super-8 airline films) actually used a proprietary TEFLON type lubricant known as VYDAX, which allowed the film convolutions to slip easily in the cartridge (but would make a roll too slippery to handle easily).

[Cohen Phillips]

FilmGuard all the way baby! To remove scratchs and to help keep the film lubed. Best thing out there. ;)

[K Borowski]

I have heard of the stuff, but am having difficulty with one roll that has scratched. I lubed it already with silicone, but the scrathces aren't effectively hidden by it. Is there some way that I should try and remove the silicone before applying filmguard? It seems that film guard is used mostly for older films, so I haven't heard anything about applying it over silicone. Also, I have heard that filmguard is a bitch to have dry. Doesn't it take days or weeks to dry film treated with this process?

 

Regards.

~Karl Borowski