Has anyone investigated using a washable lint roller as a cheaper alternative to a particle transfer roller ($1 vs $100)? As mentioned in the below patents, both appear to be polyurethane based. My concerns would be:
static charge build up and dust attraction due to possible lack of charge control agents in washable lint roller
adhesive strength of lint roller being much stronger than particle transfer roller which could damage film.
Would appreciate any feedback of other issues I should be aware of.
Background: I recently inherited 2 large boxes of Super 8 reels. I’m looking to build a scanner similar to the t-scann 8. In the past, I had paid to have 2 rolls of 16mm digitized by a local business using a retroscan. The sharpness and resolution of the scans were acceptable, but the film wasn’t cleaned before scanning and the dirt ruined the digitization. I spent a month tweaking avisynth scripts before determining that it’s better to have properly cleaned film before scanning.
I’ve never seen those particular rollers. My concern would be with the level of stickiness. For PTRs there are two common types. Kodak refers to them as “matte” and “shiny” – the matte ones are the ones I’ve seen on all film scanners that have PTRs. The shiny ones are significantly more tacky, and caused issues when we tried to use them on our 70mm scanner. We switched back to the matte ones. Static will always be an issue with PTRs, especially if the ambient humidity is low and you’re winding fast.
That being said, a PTR shouldn’t really be looked at as a cleaning device. Its primary purpose is to remove incidental surface dust. If your scans had noticeable dirt on them, odds are it was caked on gunk that built up over the years. A PTR won’t work on that.
If your film is really dirty, your best bet is to just hand-clean it. You can do this with specialized film cleaner (please don’t use stuff like Film Renew or film guard, which mostly just coats the film in oils that make a terrible mess of any machine you run it through (and will damage your PTRs if you go that route too). We get film treated with this stuff and we clean it off before we run it through the machine because it makes a mess.
99.95% Isopropyl Alcohol works well. Don’t use anything less pure though as it will contain water. Just get some Pec Pads, soak them in alcohol and wind the film through it, changing the position on the pad frequently as as you see it starts to get dirty. You could also use perchloroethylene but please, please wear a respirator and gloves if you do and work in a very well ventilated space. It’ll do a great job of cleaning but it’s a really nasty solvent.
FilmGard is a product that fills film scratches and softens them.
It is a wonderful product for making WetGate. But you have to use a few drops on a cloth and no more.
It retains dust well and I’ve never had any damage using it on my machines, but I don’t use a PTR.
Otherwise, there is also rectified gasoline (I don’t know the name in English), which removes the small encrusted black spots very well.
But here too be careful, the scotch collages do not survive.
If we have a very dirty film, the ideal for me is a first pass with a microfiber cloth soaked in rectified gasoline and then another pass with isopropyl alcohol just before the capture window.
The term doesn’t appear to be common in the U.S. I’ve been using ChatGPT recently and was able to glean the following from a conversation with the a.i.
In the rectification process, gasoline is distilled into different fractions, including naphtha. The naphtha fraction can then be blended with other gasoline components to produce a final gasoline product. Therefore, it is possible for rectified gasoline to contain naphtha as one of its components.
It is important to note that the composition of rectified gasoline can vary depending on the specific refining process used, so the relationship between rectified gasoline and naphtha can also vary.
That should be fine. We use 99.95% or higher. The key is not to go too fast, so that the alcohol fully evaporates before it hits the takeup reel. what you don’t want is wet film wound against film, because that will cause damage. it’s easy to see that alcohol has evaporated. Just keep a desk lamp pointed at the film and you can watch it disappear on the takeup side.
I’ve never seen data on the refractive index of FilmGuard. but if it’s not the same as (or extremely close to) the film itself, there’s not much point. We’ve been over this here in the past and I’m sure to start a holy war by bringing it up again, but a wet gate works when ALL of the following conditions are met:
The scratches are on the base side of the film
The solvent used has the same refractive index as the acetate base of the film (typically perchloroethelene)
The light source is collimated (focused into a straight beam through the film)
The film is held absolutely flat while fully immersed in the liquid (typically in a gate that has liquid feed and recovery ports built in, and a glass viewing port at the gate).
There are scanners (like the FilmFabriek HDS+) that run the film over an alcohol soaked sponge wheel before the gate. This makes the film wet. It is not a wet gate, despite what they say.
Will that (or FilmGuard) possibly fill scratches slightly? maybe. But you’ll only really notice the effect if your light source is collimated. Why is this? Because when the light is traveling in a straight line and hits a scratch in the base, it refracts in the same way light does through a prism - because that’s essentially what it is. This makes the scratch visible. If the light source uses an integrating sphere or similar method to heavily diffuse the light, then the photons are traveling at all kinds of crazy angles through the scratch, effectively concealing it. No wet gate will completely conceal very deep base scratches, or scratches of any depth on the emulsion side.
Part of the issue with coating the film in something and thinking that it’s the same as a wet gate is that it may not be coated evenly. It may kind of work, but it will likely introduce other issues. In the case of the filmfabriek scanner, you’re basically putting a layer of alcohol on the film, which wants to evaporate. If there is more or less alcohol on the film in different areas, it may result in an uneven layer, which could affect focus, or even subtly affect the brightness of the image. Basically, it’s not a wet gate, and the reason wet gates cost huge money on film scanners and printers is because they’re complicated devices.
I’m guessing it’s going to be something like “hydrotreated naphtha” in English. This conservation treatments page lists a bunch of perc alternatives for cleaning film and all of the “Excellent” entries are basically the same thing after you dig up their CAS numbers.
Even more interesting: the same CAS numbers can also be found in lighter fluid and “odorless paint thinner”. In particular, the MSDS sheet for the “Sunnyside” brand of odorless paint thinner shows the formulation is 100% hydrotreated naphtha with the same CAS number as the entries in that table. (That is vs. something like the Mona Lisa brand of thinner which is a 50-50 mix of a couple different kinds of naphtha.)
It’s probably a little riskier to bet on the purity of the chemicals used in a low-cost paint thinner, but you can get gallons of the stuff rather cheaply vs. trying to find the exact, pure chemicals listed in that table. (This half-liter bottle of “real” Isopar G is something like 5x the cost of the odorless paint thinner but it’s most-likely the exact same stuff.)
No. No wet gate fills emulsion scratches. the idea is that the solvent used refracts like in the same way as the base of the film. So the intention is to prevent light directed in a straight line through the film from refracting of of scratches by filling them with a liquid that temporarily mimics the base’s refractive properties.
I hadn’t seen that film cleaner yet. Nice, thanks for sharing. It looks like it has a lot in common with the Kodak P-200. I always wondered why Kodak opted for HFE 7200 when their own research showed that naphtha was better at cleaning and much cheaper.
Bringing this back around to the subject of the thread, Cinetech mentions “soft nap Dacron buffers” in the specs for what they’re using in the middle there. Those look like simple paint rollers, albeit with a softer nap than usual. I wouldn’t call them an alternative to a PTR and would be wary of using one dry, but with a little Isopar G wetting it, it’d probably do a great job at cleaning.
My understanding is that the reason for HFE is that you don’t need special ventilation to use. For Naphta you definitely do, since it’s highly flammable. For the Alcohol based cleaners, you need to ventilate it but before we installed a permanent vent cap in our last office, we did a few short jobs ventilating our Excel 1100 into the room and it was ok, with the windows open. not ideal though, so you really want a permanent solution for that.
They’re paint rollers basically. The Excel uses a combo of wet and dry rollers: peristaltic pumps saturate the wet rollers, of which there are four. Then the film goes through 4 “dry rollers” which are spaced a little farther away from the film and aren’t soaked in alcohol. it then goes through a drying box and some PTRs before hitting the takeup reel. We’ve never seen it scratch a film. It’s a good setup.
Here is the product I use.
Do not use with film that has tape sticking.
And whether it is iso alcohol or benzine, these products should not be used with films whose soundtrack has been pasted after the development of the film.
I find gasoline more effective than alcohol for cleaning.
It is true that using FilmGard is not a real wetgate, but do not play on words, this product already reduces scratches.
I’m not playing with words. A wet gate is a specific thing that’s been around in the film world for decades. What it does and how it works is well understood and the term has a specific meaning. Manufacturers like FilmFabriek have started calling their systems “wet gate” but they’re not, in the traditional sense, at all.
What is the refractive index of FilmGuard? I can’t find that information anywhere. Film-Tech manufactures it as far as I can tell, but they release no technical information about it.
That said, we remove this crap as soon as we know it’s there. It makes an awful mess of the the scanner, permanently staining the Capstan and PTR rollers. It also leaves residue on all the stainless steel rollers and in the gate. none of that is good for scanning because it can trap ambient dust, which can wind up in the gate. Believe me, I’ve seen it happen.
It’s all in the amount of product used.
This is the main mistake made by many users.
And it’s true, I don’t have any capstan or PTR rollers to judge.
But it is also a product used for many years by projectionists, but no fouling occurs on the projection windows and on the drive rollers.
I have only one regret, it is that I can no longer obtain this product, because it is forbidden to import, because the manufacturer does not give its composition (perhaps a mixture of camphor oil and of solvent with an addition giving it this color).
But let’s not get angry, everyone has their practice.