Film Gate - flattening with minimum friction


#1

Gate

Through which all film must pass!

The gate is terrible in the original Kinograph. Looking ahead, there are some basic factors to keep in mind:

  • minimize friction
  • keep warped film flat
  • interchangeable design for 35, 16mm
  • material choice (metal, plastic, wood)

I’ve actually seen a gate with wooden rails in a Russian projector so it’s not totally crazy to mention it here. It does well with heat, and balsa (or similar) has low friction coefficient. I’m just saying it’s an option. Maybe not the best, but an option nonetheless.

Here are some shots of gates that exist in the real world:

Flickr album of existing gates.

Common design elements are:

  • guides for lateral (side-to-side) movement
  • raised edges where sprocket holes and film edges touch the surface
  • pressure plate on opposing side to gate to keep film flat

Ideally, we would come up with a design that is easy to swap out. The Scanity has a good-looking system (never tried using it), and the Retroscan looks like it has a smaller version of the same thing. A single piece is swapped out in both cases. I’d like to avoid needing to keep track of more than one part and using more than one tool.


#2

What about a wet gate as a solution for gently flattening and maximize quality and avoid scanning the scratches?

First of all, always wondering me if there’s a possibility to modify a Nikon Coolscan 4000ED’s Firmware for taking 16mm and 35mm film (modifying the gate for 16mm film too), and then the possibility to modify the wet mount system given, for example, from scansciene.com.

Now i’m following the kinograph project because i don’t have no knowledge to hacking firmware, but i’m wondering, in my ignorance, if a wet mount system could help flattening and avoid scratches on old and very used films. The key is a system who cleans the film after the scan/photograph section.

Arriscan uses a wet gate, for example. (http://www.arri.com/archive_technologies/archive_challenges_and_solutions/arri_solutions/wet_gate/)


#3

I have built a few wetgate systems, and in all honesty you can get almost identical results using filmguard, and scanning the film before the filmguard dries out. This negates the need for a complex wetgate mechanism, and also protects the film against damage feeding through the scanning mechanism.

As for flattening, we are referring to stopping the film from warping across the exposure area of the plate, wetgate doesn’t help with that any more than any other clamping system really.


#4

I’ve read a lot about FilmGuard but haven’t found out where one can actually purchase any :stuck_out_tongue:

Also helpful would be how to build a film guard applicator as an alternative to the very expensive commercial one. Maybe a 3D printer project?


#5

It is easy enough to apply manually, you just spray it onto a pad and run the film between a pair of rewinds, holding the pad in the middle.


#6

@Peter I’ve also heard good things about Filmguard. It might be an interesting add-on piece that could be attached at any point in the film path before the gate. Applicators could probably be made relatively simply but I’m totally guessing.

@MikeThibault I came across a post on the AMIA list (which I never check and should start) that had a link to where you could buy Filmguard. It was also pretty informative regarding cleaning film in general. I’ll post that below. Here’s the link to Filmguard from that post, which also shows the mechanism mentioned by @Peter.

@juanjullian I’m curious to see the wetgate system you menionted from “scanscience.com.” I tried going to that site but there is nothing there. Is there a typo in your link? Thanks for starting the conversation!

Here’s that AMIA post by Leo Enticknap:

You essentially have three options: hand cleaning on a bench between two rewind heads, an automated arrangement using dry web media cleaners and/or PTRs, and ultrasonic film cleaning machine.

Hand cleaning is cheapest, but the most time consuming option. It basically consists of using a lint-free cloth saturated in one of a number of proprietary film cleaning products on the market, e.g. Filmguard, Renovex or Gentech. As they are proprietary (i.e. the full list of ingredients is not published), some would argue that the use of these solutions is not a good idea in relation to the “do nothing irreversible” principle of archival conservation, because ultimately we don’t know if treating films in these solutions is reversible or not. However, they are widely used and are one possible approach.

There used to be machines that automated the process of cleaning films by passing them through dry web media pads saturated in a cleaning solution. RTI made several models in the '70s and '80s that sold well to school authorities and non-theatrical distributors for cleaning the 16mm prints they had in circulation. They occasionally come up on Ebay, but as the media pads are no longer made, a solution for that will need to be improvised. I am not aware of any new models currently in production. There are people who have built their own cleaning solution consisting of motorised rewind heads (e.g. Kelmar), a media pad assembly (such as the one illustrated on the Filmguard page linked above) and/or a set of three of four PTRs.

Ultrasonic cleaners are the most effective, but most expensive solution. You’re looking at six figures for a new one, and at least five for a reconditioned one. The chemical used in most of them, perchloroethane, or “perc”, is acknowledged to be a totally non-invasive and thus reversible treatment (it leaves no trace on the film surface), and therefore safe for use on archival film elements. However, it also requires special handling considerations. In some jurisdictions you need a licence to have the stuff on your premises.


Film Path - (35/16mm) references
#7

Sorry for absolutely late reply.

basically, its a plate where the film is placed between two glasses at the sensor’s front place. Between the glasses and the film you have to put a liquid. With this liquid you got: 1) filled scratches; 2) a lot of sharpening and details that you can’t get with dry scan.

Arriscan have the wet gate (https://www.arri.com/archive_technologies/archive_challenges_and_solutions/arri_solutions/wet_gate/)

For more information:

http://motion.kodak.com/us/en/motion/support/people_and_planet/regulatory_resources/perc_use_for_wet_gate/default.htm


#8

HFE 7200 is Kodaks film cleaning solvent. It is kind of expensive, but they now sell it in smaller batches. Some of my customers use it in the Prista film cleaning machine and it works well. The PTR,s take of the “loose stuff” dust, lint, hair,…and then the HFE 7200 takes of the finger print oils, and tape residue and even some mold if its gone that far. It doesn’t work as will as perc., Hydronapthta, etc. but it is much better for the inviroment and your health.


#9

Not totally sure, but I don’t think perc is available any more. That must be an old Kodak article. Correct me if I’m wrong please.
Does anyone know if ITR is still making cleaning machines?


#10

Check this out.


"https://www.flickr.com/photos/friolator/albums/72157644369553789"

https://www.flickr.com/photos/friolator/14236575131/in/album-72157644369553789/


#11

Love that idea. Checked out some of their other videos - looks like a modified old machine from the 90s. Cool rebuild!


#12

Hi everyone, I’ve been following this forum for quite a while. I recently started building my own version of the kinograph, since I have limited time to work on it I decided to start putting something togheter to experiment with, this is what I came up with for the gate:

It’s a bit rough and needs more work, but it does it’s job.
More pics here


#13

Very nice construction . keep up the good work


#14

@Rickwally I’m just now getting caught up on Kinograph forums. Please forgive me for the silence until now. I love what you’ve done here. Let me know if you have time to hop on a call so I can ask some questions! matthewepler@gmail.com