Jump to content

Robert Houllahan

Site Sponsor
  • Posts

    2098
  • Joined

  • Last visited

Everything posted by Robert Houllahan

  1. Actually it is pretty clear that negatives are scanned with (gamma cineon log) and that prints do not have that curve applied. IDK if you think you are somehow magically reinventing the wheel here but since Kodak's Cineon data scanning was invented in the early 1990's hundreds (or thousands) of billions of feet of film has been scanned with 99.99997% of all prints and other positives like Reversals being scanned as linear data with the 00.000038% having been scanned (somehow) as Log because some scanner op made a mistake. There is nothing new here this ground has been covered and re-covered and run over by artillery horses then model Ts then Chevys then Land Cruisers and tanks then horses again and a few HumVees and then a pack of dogs then followed by crows and a herd of cats. This conversation is moot.
  2. The Cineon file format was designed specifically to represent scanned film images, and thus has some differences from other formats such as TIFF and JPEG: The pixel data represents "printing density", the density that is seen by the print film. Thus, Cineon files are assumed to operate as part of a reproduction chain keeping whatever values are originally scanned from a negative or positive film. Any negative can be reproduced on the recorder retaining the original neg's characteristics (such as color component crosstalk and gamma correction) — and thereby retaining the negative's "look" if it were directly printed. The original Cineon color data metric printing densities were based upon 5244 intermediate film. Conversion of Cineon Printing Density (CPD) to Status-M can be estimated with a 3x3 matrix or by using tables contained in the Kodak "Digital LAD" document. This document shows a specific relation between Cineon Code values and Status-M densities. The data is stored in log format, directly corresponding to density of the original negative. Since the scanned material is likely a negative, the data can be said to be "gamma with log encoding". To evaluate original scene luminances from Cineon data, the camera negative characteristics must be known. (Such characterization is known as "unbuilding.") Such characterization is aided by exposing a sensitometric strip so that the actual developing gamma can be determined. The film can be unbuilt by using the unique per-layer contrasts of the color negative.
  3. I don't know how to say this more clearly. Negative scans are encoded as Cineon-Log. Positive scans are linear data. This has been the case since the early 1990's https://en.wikipedia.org/wiki/Cineon
  4. LADs are available for 16mm we use them all the time. The Kodak LAD system is not just a good system it is the system by which analog and digital elements are managed. There is no need to "characterize" the scanner. There are several systems which are used to profile digital displays and full end to end lab scanning film recording and printing to allow a colorist to grade using a digital projector which looks like the film print the lab will make.
  5. For film data scanning there is linear and Cineon-Log encoding, No other type of log encoding is used nor wanted. Cineon Log was invented by Kodak in the 1980s to scan negative films and it's Log curve matches the sensiometric density characteristic of film negative as a way to compress the linear sensor response and make the bits more useful in post. All CCD and CMOS sensors are linear devices i.e. more photons increase voltage output in a linear manor. The point of using Cinelon-Log was to take 12-14-16bits of data per pixel and scale them into 10bits. Film positives are not scanned with a Cineon Log curve they are scanned as linear data because the print is "wysiwug" and linear encoding works for that. ideally you would scan at 12bit 14bit or 16bit and just put those bits into a 16bit DPX file as linear data and go about processing from there, this amount of data becomes unmanageable for most computers and disk systems, so we have 10bit DPX and ProRes which most people use. Film scanning has never primarily been about efficient files sizes it has been about a accurate and full representation of the density scale color and resolution on the film.
  6. Film processors are kind of basic machines you could re-wire allot of it for 220v and most likely the drive motor is controlled by a 220v to 90v motor controller. Should not be too hard to do.
  7. The simplest way to describe how the scanner translates the print to digital is that the scanner sensor is a monochrome sensor and each color is then illuminated with Red , Green or Blue light and each time that light is fired then the sensor takes a picture representing the color which is then mapped into the DPX frame file as linear data. The Red Green and Blue light intensity are set by measuring the sensor output and setting the intensity of the light through the base at it's clearest so the sensor is close to but not clipping, then the rest of the sensor DR is just down to the shadows... For the Scan Station using a Sony Pregius 6.5K camera it is 12bits for single flash and 14bits for HDR double flash so that is then mapped as linear data into 10bits or 16bits for DPX without a Lin to Log conversion table. You could shoot out a Kodak Digital LAD and measure the AIM Density on a Xrirte Desnitometer, print that and measure it again then scan it and match the AIM charts to the code values in the scanned DPX frame. For prints it is all linear data. For making a film to film print there is also always the printer lights base setup and the color timer adjustments. There is no fully automated human decision free way to do film printing but there are the Kodak LAD control tools which allow a high degree of consistency to be made.
  8. How is this different than any other film scanner? I have Scanners from Arri DFT DCS and LG and none of them have any color gamut space settings, in the case of DPX they scan to 10bit log (12bit) or 16bit linear. The Arriscan for example is setup to the film base (RGB+IR LED lamp intensity) and then Linear to Log conversion with the ability to set Cineon values. Other scanners have color correction tools in the scan setup to do matching and balance etc. but nothing specific to Rec709 or 2020 etc. I think for negative they are all based on the Kodak Cineon code values from the 1980's on.
  9. As long as the film is in a bag in the can we don't generally care if it is on a core or not, I ran 1600ft of 16mm ECN from an SR3 today with no cores and EZ to put cores in to prep in the darkroom to develop. I have shot with 100ft daylight spools on both my LTR and XTR they work but they are very noisy. No need to inform the lab it is short (we will figure that out) but as Mark said definitely let us lab folks know of you send a 16mm roll in a 35mm can as that will be relevant to scheduling what gauge is run and if it is opened in the dark and found to be 16mm while prepping 35mm it goes back to the beginning.
  10. 3-phase equipment can be fairly easily run with a phase converter and that is mostly the drive motor I would guess. I would guess that my PhotoMec processor weighs five or more tons so a half ton machine is smaller in terms of film processors. If you set it up you could likely make it into a reasonable business.
  11. I do not see any examples or technical data offered or linked to within this thread to make any conclusions from. Is there any technical examples which form the basis of this assumption? I am not saying it is wrong but some data to draw from would be better than speculation.
  12. If you want modular already fully running kits with mature software for anything from Oxberry scanners to Cintel (and maybe Spirit) Chassis or any level of roll your own to a full turnkey system take a look at the Xena. It is sort of the PC of the scanner world to LaserGraphics Apple as it is allot more technical to setup and run but is now very reliable and males great scans. www.digitalcinemasystems.net
  13. We have run countless feet of Ektachrome in ECN2 the most recent recognizable job was the opener film for this season of NFL Football for NFL Films which was a mix of Color Negative B&W Reversal and 100D Ekta cross processed all with a 3K overscan. We also had a recent music video project that DP Hutch Crane did with expired VNF run in ECN2 that really did some cool color shift stuff. Very different look than running in E6. .
  14. Euphoria cross processed the 100D Ektachrome in ECN2 which is a very different look than running it as E6 color reversal. One of the aspects is that negative stocks like Vision3 have an orange base and the 100D Cross processed has a clear base. And of course you cannot project the Cross Processed film unless you make a print.
  15. Processing machines are (mostly) built with off the shelf components like the pumps the heat controls the chain sprockets etc. The parts which are film specific are the rollers for the film in the tanks and some of the shafts which drive the rollers at the top.
  16. I wonder if anyone ever sent a Personal back to get it turned into a full Scan Station? I think most of the basic components like the chassis are identical, they basically are on the two Scan Station machines I have now except the capstan is on the left on the Personal and on the right on the Archivist which is where the capstan is on most other scanners. I think LaserGraphics uses allot of off the shelf components for motors and drive stuff to keep costs down and reliability up. I have not heard of a used Scan Station for sale yet.
  17. Looks nice I assume Spectra did the E6 process? I have run both 35mm and 16mm 100D E6 On our Scan Station in HDR and I think the Scan Station does better with Color Reversal than the Scannity at Spectra does.
  18. Saw it is a FilmLab machine, there was a Co in the USA called FilmLine and I had one we ran ECP on, it was huge and old and a bit of a mess. It had a driveshaft and bevel gears for each tank so kind of complex. Chain drive is pretty simple with sprockets for the drive shafts at each tank and a "demand" roller which governs speed.
  19. Congrats! If you need any tips or help please message me. Processors have manuals but they are also pretty simple mechanical machines in many ways. Looks like a Film Line processor do you know if it is shaft drive or chain drive? How many tanks does it have?
  20. In machine ECN2 processing there are air knifes (or squeegees) between each tank to control chemical mixing so for hand processing allot more wash between steps is definitely great advice.
  21. The Bauer has a manual exposure dial and you can just bypass the auto exposure and keep it wide open. The Beauleau cameras have an oscillating mirror shutter instead of a beam splitter I believe and thus will get more light to the film for sure.
  22. I think the lighting is all over the place color temp wise, I would / have shot allot of similar stuff on both 500t and 250d and I think 500t with superspeed glass is the way to go. I would recommend a 1 stop push on the 500t even.
×
×
  • Create New...