Robert Houllahan

1 hour ago, Dan Baxter said:

FYI I could point out stuff you've said that's misleading like microscaning taking just two exposures. Microscanning was developed for scientific imaging not film scanning, it only works with monochrome cameras, and to make the matrix with the sub-pixel imager shift takes nine exposures to get to 3x the resolution (or four exposure to get to twice the resolution as used in some film scanners). So you take a 1.3K imager, 9 exposures, it's now 4K. Film scanners that do this so far as I know started with 2K-3K imagers and did only 4 shifts at incredibly high speeds.

The Arriscan was the first microscanning application to film scanning and it is one microscanning step per color.

So for 3K it is R,G,B +IR for 6K it is R,G,B +IR (step) R,G,B +IR

And for 3K HDR it is R,G,B - R,G,B + IR and 6K HDR R,G,B - R,G,B +IR (step) R,G,B - R,G,B +IR

So 14 exposures per frame max in 6K HDR and it runs at about 1.6 FPS in this mode with IR (and that is hardly used)

The ALEV Mono sensor in the Arriscan is shifted in both X and Y for the microscan

1 hour ago, Giray Izcan said:

1000ft of nc 500 is now 1916.00 dollars... hahahaha

Yeah that is intermediate stock prices a 1000ft roll of 35mm Ektachrome 100D is $1300.00 from Kodak and I thought that was a premium price.

Maybe they are just grabbing some cash for the 35mm at the rollout and maybe the price will drop later?

IDK it is allot.

Going to order some 16mm now...

I always assumed that multi flash HDR was a base feature of the Director at least from the 5K/10K on and I feel that the 5K cmosis camera is realistically a 10bit camera so 2-flash would get you 12bit and 3-flash 14bit.

I got LG to sell me the 2-flash HDR for my 5K Scan Station "personal" mostly used for 35mm and that sensor is pretty poor without it, the 2-flash really fixes most of it's flaws.

I suppose the theory behind 3-flash is to attain 16bit precision from "cots" cameras which are mostly 12bit like the 6.5K Sony Pregius that replaced the 5K cmosis.

The Arriscan and Xena pin registered scanners do 2-flash RGB and the new DFT Polar 9.4K scanner does 3-flash RGB.

"Perhaps a substitute for HDR scanning is multi-sampling?"

Well as others have said it is multiple "samples" or exposures of the same film frame and sensor at different light intensities.

The 16mm on the Orwo store is $47 for a 100ft daylight spool and $185 for 400ft on a care which seems reasonable.

The 35mm is quite expensive.

I thought this stock was based on the Agfa 320T color negative.

I shot some of that stock at school in the 1990's but I do not recall much about the look.

2 hours ago, David Sekanina said:

Thank you Robert. I knew the Arriscan does it from what I've seen at Cinegrell, but wasn't sure about the other scanners.

I think the Arriscan was the first to employ this technique, basically each color is ramped until the sensor clips and then the intensity is backed off. This maximized the DR of the sensor for each color to the sensor. In CFA scanners a similar set of pulses are done but then full RGB illumination because there is allot of color channel cross talk on a color sensor.

Fairly simple and a fast way to match the lamp to the sensor / film stock for most dynamic range and color balance.

14 hours ago, David Sekanina said:

The color of the base of the film is quite different to other color film stocks. Should scanning facilities modify their scanning procedure, and plug-in creators create a special profile for ORWO conversion to positive? Or do the current methods work well?

Modern scanners like the Arriscan or Scan Station etc. do a "base calibration" where the individual RGB lamp channels are swept through a range of intensity to find color balance and lamp output relative to the clear base. This works fine for stuff like Ektachrome that has been cross-processed and does not have the orange mask. So not really an issue with this stock I would think.

It is worth noting that the Director is a "True RGB" scanner like the Arriscan etc and uses a monochrome sensor and multiple individual color captures. Bayer mask sensors do have allot of color channel cross talk which is made up for in math and that is not always perfect.

11 hours ago, Tyler Purcell said:

So riddle me this... if I did pick up a Xena, could I pay you to make us a wet gate for it? We've been thinking about it for the future. 

Shoot me an email I am sure that could be figured out.

2 hours ago, Tyler Purcell said:

Interesting. Have you tried any of this yourself? We'd love to do ceramic parts someday. Thanks! 

Some of the re-worked RTS gates I have for the Xena scanners have really nice ceramic guides (they were something like $30-40K each back in the Telecine days) and they work exceptionally well for stability.

I have not tried to make any ceramic parts on the Form Labs printer but that seems like a really interesting material option.

I find that the ceramic guide systems on RTS and Spirit gates work really well. Basically a fixed ceramic guide on one side and a spring loaded guide on the other. They tend to distribute pressure more evenly over a few frames of film. Roller bearing guides are a bit less effective IMO.

The Form Labs SLA 3D printers can print material which is a Kiln Fireable ceramic.

22 hours ago, Dan Baxter said:

The spirit is completely different it has a line-sensor. If the film isn't perfectly steady through that then the transfer is warped and it looks deformed. That kind of design won't handle even the most slightly shrunken film because you're vertically stacking lines to make a picture.

I have three DFT Spirit 2k/4K scanners of the very last generation and I can tell you that they can scan shrunken film and make very good scans. These machines use 4K 3-CCD linear sensors and have excellent color and DR they are just costly and complex to run in 2022.

A Spirit 4K was $2M in 2008 and the machining work that went into building the film transport and gate(s) far exceeded the cost of building many more modern CFA based scanners. The Scannity is still the "goto" scanner for many high end jobs for TV and Film and it too can scan shrunken and damaged film with good results.

The Spirit like the Cintel DSX etc. uses a very high precision sprocket encoder in the gate to "time" the scan and a secondary capstan encoder for the servo and so the scan registration is not based on the irregularities of the rubberized capstan. I know sprockets are "not modern" but really well made sprockets can be used with shrunken and damaged film quite effectively.

The Kinetta / Xena / Scan Station all use a high resolution capstan encoder and GPU machine vision pin registration now.

I cannot imagine having to use a scanner without that these days, secondary perf detection to fire the camera (laser or sprocket) without GPU stabilization just does not yield the same results. Having to do post stabilization is just ridiculous at this point and with the amount of film we scan as a lab it would be a completely impossible workflow.

One thing I do like about the Xena perf stabilization is that you can select X-Y or X or Y only and there have been some very difficult films that has helped me scan.

The Track Perf pin registration on the Scan Station works 99.8%  of the time totally reliably in my experience.

8 hours ago, Tyler Purcell said:

The Scan Station does not need to have perfectly optically aligned film. Have you seen how bad the alignment is without the computer stabilization? It's really bad actually, way worse than our scanner.

I scanned 25ft of 16mm ECN ( which did not have perfs at all ) two days ago on the SSA and it was decently steady enough for that film ( from a Minox ) and the frames were steady enough to be worked with.

The Scan Station 16mm and 8mm gates do have a set of roller bearings on either end of the gate to get the film basically in position.

Looks good to me!

We just ran a Music Vid shot on an SR3 HS with Hawks and it looks great but I know the glass was expensive to book.

2-Perf will as others have said look finer grained and will overall be easier to source camera and lens kit for.

LG will do some upgrades to a SSP if you ask enough...

12 hours ago, Carl Looper said:

There is no suggestion in the posted description of cineon encoding that positives (as distinct from negatives) would be encoded in linear rather than log.

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.

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 minutes ago, Carl Looper said:

I would have assumed the Prores encoder would use gamma encoding, rather than storing linear or log data. Or is that not correct?

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

On 11/23/2022 at 4:23 PM, Carl Looper said:

Kodak LADs are good for calibrating printer lights, but as far as I know, they are not available for 16mm. I wish they were ! Nevertheless the basic idea behind a LAD is a good one. A LAD can be spliced to the head of a print, providing the means by which to characterise whatever transfer function is being used by a scan. 

Once a scanners transfer function has been characterised, software can be written to emulate, on a computer screen, what the film would look like when projected on an analog projector.

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.

On 11/23/2022 at 4:23 PM, Carl Looper said:

Linear encoding is probably the safest option for a scan (involving the least number of assumptions in downstream processing) but it is also the most inefficient in terms of file sizes. Any "corner cutting" on such, (e.g. dropping bits) is going to compromise the data faster than if the scan was encoded in any of the non-linear ways it might be encoded. The most conservative non-linear encoding will be linear to Log encoding.

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.

20 hours ago, Gareth Blackstock said:

I had a quick conversation with an electrician regarding 3 phase converters, he said that while a converter would likely get a 3 phase machine running, once the machine started drawing big power the converter would fail. And getting 3 phase connected.... thousands. 

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.

16 hours ago, Dan Baxter said:

For reference I think the price for a good refurbished fast ones like they use in wetlabs in the US through MMT is around USD $50K at the moment and they come ready to go with all the required tanks etc.

Ha more like $150K-$200K if you can find one.

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.