Jump to content

Guy Burns

Basic Member
  • Posts

  • Joined

  • Last visited

Profile Information

  • Occupation
  • Location
  • My Gear

Recent Profile Visitors

2586 profile views
  1. If you do try Warp Stabiliser, it is probably best to stabilize the sprocket holes and not try to stabilize the entire scanned image. That's why overscanning is needed. Select the sprocket (or the part of it you have scanned) and stabilize on that, bringing the rest of the frame into stability.
  2. Hi Domenic, Good to see my old thread is still useful to someone. The machine's owner was unable to fix the problem. As part of the testing, I used Premiere's Warp Stabilizer to bring the frames into alignment, and that worked well – but you must overscan.
  3. Thanks, David, for the waveform. I'm new to DPX, so every little bit of extra info helps in my understanding. And to repeat something from a previous post of mine: for anyone who has downloaded the files, I'd be most interested to find out if you can turn the DPX into something that looks similar to Test Excerpt (graded). The operator can do it in Resolve, supposedly with a simple levels adjustment. I'd like to know if it really is that easy, or if there is fancier grading involved (possibly a workflow suggested by Filmfabriek?)
  4. Thanks for the comments. The test film is Super 8, positive. I find it difficult to accept that the scanner may not have been set up correctly. However, after he adjusts levels in Resolve, the operator is able to deliver scans in ProRes 4444 that, to my eye, appear good quality. Someone else is having a look at this problem for me using the latest Premiere. I run CS6, and he had me almost convinced that it was my system at fault. Something about CS6 and 8-bit. Maybe it is, but I'll wait till he gets back to me before I think about moving to a newer Premiere. This young fellow with his new Filmfabriek is really trying to do the best he can. It's hard to believe the problem is with his scanning. QUESTION I always specify to operators that I want manual exposure (clear film to be max RGB, unexposed film to be min RGB, or other settings they think gives the best result); slowest recommended scan speed; and no auto corrections of any kind (sharpness, contrast, colour). Yet too often the scans have been problematic. I've ended up with about a dozen scans of my test film because I always ask for (and pay for) tests at various scanner settings before giving the go ahead on the real films. One operator told me that scanning at his normal speed gave perfect results, yet my test at half speed was sharper (Muller HDS+, UK). That wet scans offer the same quality as dry scans, yet the wet scans had obvious colour differences (UK again, and Filmfabriek had to step in and upgrade their software). That film white will be scanned as maximum RGB, but comes back obviously blown (ScanStation, Denmark). Is scanning at high quality on an expensive machine difficult to do? Is there something I'm missing?
  5. David No particular reason that I wanted to use ProRes except it seems to be a common delivery file. Before this slight problem turned up, I didn't even know what DPX was. But now, after testing the DPX files in Premiere, they certainly slows things down on my system, so I'll be sticking with ProRes. Downloads • The DPX files can be downloaded in a zip, here. There are about 100 of them, 1.8GB. Or you can download just the first 10 here. • The corresponding ProRes 422 files can be downloaded here. There are two ProRes versions in the zip -- one is direct from the DPX, called Test Excerpt (original); the other has been level-corrected by the operator before transcoding to ProRes, called Test Excerpt (graded). My attempts at grading I've loaded the three files into Premiere, lined them up, and tried adjusting the DPX files so that they appear similar to Test Excerpt (graded). I can't do it. Using RGB Curves, there's no way I can achieve the same look. The problem is in the shadows. No matter how much gain I apply, there is always a certain amount of straight line bottoms as viewed in the RGB Parade. So, I've made the decision to let the operator adjust levels, and deliver to me in ProRes 4444. I'm also going to ask him for one more scan of the test file, this time to Tiff. He doesn't mind me doing all this testing, cos I'm paying top dollar. Anyone Else? If anyone wants to experiment with the files, I'd be most interested to find out if you can turn the DPX files into something that looks similar to Test Excerpt (graded). And I'd like to know how you did it.
  6. Daniel In hindsight, maybe I should have asked for the scan to be output to Tiff. But I thought I read somewhere that Premiere (I'm running CS6) doesn't import Tiff at full resolution, only 8-bit. That's why I chose DPX for the test scan. Shootout As for the scanner shoot out, even though I have a dozen or so scans of the same reel from various machines at various settings, the shootout wouldn't be between machines, but between how the operators use their machines. So it would mostly be a test of operators. The most pleasing scans of my 8mm test film have not come from the Lasergraphics ScanStation, but from the Filmfabriek -- because the operator of the Filmfabriek has taken the most care. The ScanStation (costing five times the price of the Filmfabriek?) gave me overly-sharpened images and blown highlights. That's not the machine, that's the operator. As with all machines (cameras, scanners, power tools) -- above a certain price level, the quality of the output does not depend on the machine, but the operator. That's why I want to encourage this young bloke in Melbourne, a one-man band with a Filmfabriek, to do the best he can with his new toy. I can ring him and he answers the phone. I email and get a prompt response. If there's a problem, as with this ProRes 422 thing, he's wants to get on top of it: "I have investigated this further and have narrowed the issue down to using the ProRes422 codec." Whether or not that's the real issue, is yet to be determined. DPX to ProRes I want to work out where this DPX to ProRes 422 problem lies. I'm new to DPX, but have been reading and thinking about it a lot. I'll make some comments below to test my understanding of DPX. No need for detailed correction if any of them are not quite true, but if any of them are definitely wrong, please say so. DPX is a file type that tries to capture the intensity of light in a way similar to human vision: sensitive in low light (more bits required to capture different levels), not so sensitive in bright light (less bits required). This variation in bit-intensity, reduces the number of bits required to capture a range of light intensity. If this intensity-data is displayed unaltered on a computer monitor, the image will not appear as it did in real life. It will be washed out. That doesn't really matter, because the image will be altered anyway to achieve a certain look (colour, contrast, sharpness…). It is not necessary to start with an accurate portrayal of the original if the image is going to be altered. However, if you do want an accurate portrayal of the original image (say, because it's an historic image), you've got a problem. How do you get the original image back from the distorted intensity-data? You need to know the maths of how to do the reversal. There are certain file types that will capture intensity-data in a way that will display images correctly on a computer monitor: Tiff, ProRes… A conversion from DPX to any ProRes flavour should appear virtually identical when viewed on screen. Questions 1. What is still unclear to me is how does a scanner operator convert DPX to ProRes accurately? When Rob Houllan uses Resolve to convert the DPX output of his various machines to ProRes, who provided him with the reversal maths? The manufacturer of the Xena, the ScanStation, the Spirit, the Arrilaser? 2. Does he have four different LUTs (not that I know what they are), that he enters into Resolve? 3. Or is the reversal maths somehow encoded into the DPX itself, as metadata? 4. If I do happen to get hold of the DPX files for my scans, and assuming I want to see images on my iMac screen that look the same as on film, will that be possible in Premiere? In Resolve?
  7. Two comments from the operator. For my scans, "colour grade" means levels adjustment only. "My workflow is colour grade the captured dpx files in Resolve, export to Uncompressed QuickTime 10 bit RGB files (as the scanner software is on PC I can’t directly export to ProRes hence the uncompressed transcoding), then convert the uncompressed to ProRes via Adobe Media Encoder." "I am still confident the issue is that the chroma subsampling in ProRes422 (being 4:2:2 vs PR4444's 4:4:4) is noticeably ill-equiped to translate the sparse black and shadow detail of colour reversal film in a flat scan." I have yet to see the DPX files. They should be uploaded soon.
  8. Thanks for the responses. I've asked the operator for details of his workflow, and also for 10 seconds of DPX. As soon as I get them, I'll post.
  9. Thanks for the response, Phil. This problem has started me thinking that maybe I should be asking for the scan to be delivered in DPX. The scanner outputs DPX as 10-bit log, but I don't think Premiere will like a log file. I'm going to ask the operator for 10 seconds of the DPX files so that I can test them, and I'll also upload them so that anyone who is interested can play around and make suggestions.
  10. I have just had some test scans done into ProRes 422, from an 8mm home movie (my reference film), prior to going ahead with having an historic 8mm amateur film scanned into ProRes 4444. The historic film is from the late 1960s, and documents a scientific survey of the now-flooded Lake Pedder in Tasmania. So I want to get the scan right. Over the years, I have had the test film scanned on a RetroScan, Muller HDS+, and Lasergraphics ScanStation. So I’m familiar with how the scan should look. The present machine is a Filmfabriek HDS+, scanning at 2.5k. For the test, I asked for a raw scan into ProRes 422, with no corrections of any kind. The raw output from the scanner is DPX. The operator, using a PC, converts to ProRes 422 via Quicktime. I was very disappointed with the test. Viewing the RGB Parade in Premiere, the blacks seemed to be clipped at 20%. That ugly straight line effect that looks so unnatural. And it couldn’t be graded to approach the look of any of the previous scans. I brought the problem to the attention of the machine’s owner. He consulted his DPX files and said he could see no problem. He first suggestion was that compressed ProRes 422 was causing the problem. We couldn’t agree on that because from my point of view, 422 is 10-bit and a pretty good codec. After a few emails and phone calls, he then suggested that he revert to his usual workflow and alter the levels of the DPX at his end before converting to ProRes 422, so that the image range was from about 5% to 95%. He sent me the new file and it looked pretty good. He now thinks the problem is with his workflow, and so do I. Somewhere in the conversion from DPX to 422. But we’re not sure. Ques 1 Is the quality of ProRes 422 such that there would be a significant difference between it and DPX at the low end, at around the 20% level? Ques 2 Or is it more likely that the conversion is being done incorrectly? Ques 3 Why would changing the levels of the DPX file by a relatively small amount (originally 20 -75%, later 5-95%) make such a big difference to the 422 outcome? A 6-second snippet of the original 422, and the new level-adjusted 422 can be downloaded here. Any suggestions most appreciated.
  11. Thanks for the responses. I contacted Carlo in Switzerland. He said his machine wasn't suitable for scanning 2000 feet: Too slow for the amount of footage you have to transfer. Hope I can have a real production machine ready in the future, but this would not be a very fast one either as I stick to real frame-by-frame approach, not the continuous type of machines which now flourish on the market. In terms of quality, the faster can't be the better. His comment "the faster can't be the better" is what my Q4, above, was asking. Reel One, Finland, might be a possibility, but isn't the Cintel Millennium 2 quite an old machine?
  12. I have 2000 feet of 9.5mm film on five reels, taken in the 1940s and 1950s. Movies taken by a deceased friend, of family and wild places in Tasmania, parts of which will end up on Blu-ray. I want it scanned at 2K on a high-end machine such as a Lasergraphics ScanStation, MWA FlashTransfer Choice, or similar. As far as I am aware: no company in Australia has such machines. Images4life.uk has a FlashTransfer, but the cost increases by 50% to convert from DPX to ProRes 4444, and another 50% if I ask for transfer at a slower scan-rate (10 fps instead of 15 fps, recommended for improved quality) videopro.dk have the ScanStation and a lower resolution model of the FlashTransfer, but from my experience there are language – and other – difficulties. I have been unable to track down anyone else who can do this work. This leads to several questions. Below, when I mention scan-rate, I mean the number of frames scanned per second. Scan Companies Ques 1 Does anyone know of a company, anywhere in the world, that can scan 9.5mm films using a high-end machine? i.e. something better than a Retroscan. The company must be happy to deal with a home enthusiast. Some aren't. Exposure vs Scan-Rate Ques 2 Is exposure time when scanning, linearly dependent on scan-rate? i.e. double the scan-rate and the exposure time halves? Ques 3 Or does the exposure time vary non-linearly with scan-rate? If so, why? Ques 4 How does varying the scan-rate effect the quality of the scan? For instance, does scan quality inherently go up as scan-rate goes down? What factors are involved? Ques 5 For a 2K scan of an 8mm film, what would be typical exposure times for a certain scan-rate? Output Format The films are mostly amateur B&W. During editing in Premiere, all the scans will need a goodly amount of contrast correction, and a small number will require significant boosting in the shadows. Ques 6 Assuming that shadow detail is actually on the film and can be captured by the scanner, does 4444 holds extra information in a form that would give obviously better results than 422 HQ when grayscale shadows are boosted significantly in Premiere? Personally, I doubt that 4444 is worth the extra file size for these films. But I thought I'd ask, just in case.
  13. Thanks, Satsuki, for the suggestions. Since I've had limited response here, I've taken my questions to the Film-Tech forum (http://www.film-tech.com/ubb/f16/t003048.html), and they've provided some detailed suggestions.
  14. Background I'm converting my three-screen audio-visuals to Blu-ray format, with the aim of presenting them at the local cinema. Basically they're slide shows from the 80s and 90s, with a few added clips from my GH3, and new soundtracks. I'll let a few friends know, and they can pass the word around. It's just a hobby, but I want to do the absolute best job I can. Editing is in Premiere at 23.976 fps, and all slides enter Premiere in sRGB. Video output if rendered to m4v format at 20-35 Mbps, and passes through Adobe Encore (without transcoding) onto a Blu-ray disk. What I see on my iMac screen is pretty much what I see on our 3-metre home theatre screen – my test bed. At the Cinema What I am concerned about is how the presentations will look and sound in the cinema. I've had a short tour of the projection room. They run four Barco projectors… https://www.barco.com/en/Products/Projectors/Cinema-projectors/Lamp-based-cinema-projectors/C-series/Compact-DLP-Barco-Alchemy-Cinema-projector-for-screens-up-to-20m-65ft.aspx#!specs … and the operator assured me the setup can accept HDMI input. So my idea is to take along my Oppo Blu-ray player, a HDMI cord, and have a test run. I will only be allowed 5-10 minutes of testing. Questions ​Before I go to the cinema for a test run, I want to have a pretty good idea of what to expect, and where problems might occur. Thus these questions. Ques 1: HDMI The Barco processor has one HDMI input, but the specs make no mention of a 23.976 frame rate. Does having a HDMI input imply the Barco will work with all signals from a Blu-ray player, including 23.976 fps? Ques 2: Gamma My entire workflow is in sRGB (with a gamma of ~2.2), from scanner (or GH3), to my iMac, through to my BenQ W7000 projector. However, Cinema projectors, I read somewhere, have a gamma of 2.6. What effect will that have on my images? Will the effect be noticeable? Should I correct for it? How would I correct for it? Ques 3: Test Material The best test material would of course be the actual presentation, but I'll be limited to only a few minutes of projector time. My idea is to take along on Blu-ray disk: 1. A projector Calibration Pattern for Blacks (levels 0 - 16). 2. A similar pattern for Whites (levels 239-255) 3. 30 seconds of a typical dark scene 4. 30 seconds of a typical bright scene Items 1 and 2 are not for calibrating the Barco, of course. If levels 0-16 all appear black, say, I'll have an indication that something's not right. Are the four items listed above, the most suitable? Ques 4: Sound Is there a loudness standard for films? All my audio is matched to ITU-R BS 1770-2. My guess is that the cinema runs a constant volume setting on their amps, a setting which suits most films. And I'd rather not ask them to change that setting just for me. Thanks in advance for any comments.
  15. ICE came out of Applied Science Fiction – and that's just what it is. To be able to remove, almost perfectly, thousands of dust spots in a few seconds is akin to magic for me. You can download an example here: http://www.mediafire.com/download/kec2iw6jstsydoa/GM126.tif It's a large file (100 MB) scanned at maximum resolution on my Coolscan. Taken in November 1964, probably on Agfa. Two layers, one with ICE, one without. Jump between the two in Photoshop and you'll see magic in action. I generally use two layers so that I can mask areas of the image where ICE is not required and in which it may cause problems; or areas where I want to manually clean. If movie-film scanners had ICE, it'd just about put restorers out of business.
  • Create New...