I started off by finding out that "Polyethene" and "PET" film are the same thing. I have a feeling that there's a roll of PET out there that isnt' called "Clear PET roll" because the only market for that at the moment are businesses selling to other businesses (story of #Filament Furnace [gd0042] ). This log is the research I've done over the past 24 hours:

• While it would've been truly convinient (since this was the first thing I found when starting to google), Acetate is not a suitable material.

• Unfortunately, the film on these "self adhesive" PET films is a thinner PVC film. I was hoping I could just peel off and discard the sticky film.

• The vast majority of films are much wider than 20cm. Like 60cm and up. 

• This film could be an option if it can be cut into sections of 20cm.

  • It's a film that has a layer of silicone on both sides. It's used for things like transparent film that stickers are packaged on. Vat + shipping brings the total to £45.

• Clear sequin film would've been an option if only it was wider. Widest I could find was 125mm.

• This might be an option...

  • The only issue could be its thickness. 
  • But wait a moment. Don't people use screen protectors with their resin printers?

  • Ooo look at the bottom bullet point. PET is used for screen protectors here. That means that the PET shouldn't filter out wanted UV light and confirms my expectation that PET is so durable that it'll also protect the screen in the Suspense. 

  • 1 tear. Singular. "Don't do that... don't destroy my hope.". They've also got the same thing at another listing, but doesn't have the "10 Pieces" text so I don't know if they're charging £10/m or something. That's FEP prices. 

• I knew this business was business to business. I can't imagine how much PET is on that roll.

  • • Cool to see how these packets are made though.
  • I asked the seller and they said that they can't really measure under 4kg. With this in their description, it makes sense:

• I found this listing yesterday and have just seen the response:

  • The thing is that it's still the wrong size (so I'd have to figure out how to cut a long roll adequately straight, and it's £5/m which is not great, not terrible. Additionally, I don't want to buy from some lone ebay seller (see #Filament Furnace [gd0042] ) for which I'm here to unironically buy his/her entire stock:

• Hmm. I've been looking at a lot of listings now and my mental neural network says there's a high probability that this is clear PET not polypropelene or silver-coated mylar or vinyl or B Film for some DTF machine or the sublimation stuff for inkjets (this is the best I could find the last time I searched. It's where the £40 PET estimate came from in this log)  the other trap cards on this journey across the web.

  • YES FINALYY!! After all these years... I've found it. I knew it wasn't going to be called something standard like "PET film".

  • I found another listing which states how much I can expect to be on a spool. 

• Ok then so does the cake industry just use whatever is transparent and available?

  • Seems like it

• • Oooo some PET. *clicks*.
  • Acetate again?! Don't say PET on the listing and ace-- wait. Is it one of those things where they say "acetate" but just doing that to get into search listings and instead use a more modern/available material?
  • The first roll I found is actually made from PP. Interesting...
  • A bit more searching reveals that PP that's used most of the time and the £6.94 and £36 stuff is the only allegedly PET ones I've found. Well I only need 10m of the stuff so I can finally get out of a search.
  • [a few hours later] 
  • Found more instances of PET film. I had to go through a few listings but it's there. Considering that resin prints don't usually have to span over half a metre, it's probably better to go with the thickest stuff under 250 microns or so.