Retro Telecine

Building an 8mm Telecine Machine with Style

Tuesday, January 13, 2009

Workflow

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Here’s my transfer procedure…

1) Turn on the clean booth fans, put the machine, film and cleaning stuff in the booth. Connect power and turn on the LEDs. Connect camera USB to computer. Blow out projector gate with Dust-Off.

2) Start TelecineApp.

3) Clean the film in the booth.

4) Load film on machine and run to start of first scene.

5) Setup for first scene…

Brightness: 64. This is the luma gain applied after all the other processing in the webcam chip. 64 represents a gain of 1 and I normally leave it there, since it can’t do anything useful that the post processing can’t do.

Saturation: -20. This controls the chroma gain at the end of the process chain. After all the other adjustments, I may tweak this to taste.

Gamma: 31. Normally, I have gamma all the way up, but a few scenes have a smaller range (the histogram spread is narrow) and reducing the gamma will take advantage of the extra range available and make the scene snappier.

White balance: After exposure is set pretty well, I turn on Auto WB until it settles, then turn it off and fine tune. The Philips Auto WB is pretty good, but the result is usually a little cool for my taste, so I usually turn the blue down a bit to warm it up.

Gain: 0. Gain is applied to the analog signal from the CCD, before the A/D converter. So it’s good for maximizing use of the 8 bit range when the shutter speed is not ideal.

Shutter: Start at 1/250 and increase exposure until the highest histogram is almost (but not quite) at the top. Use a little gain if the best shutter speed leaves more than about 15% of the range unused at the top. NEVER OVEREXPOSE! The movie will look a bit dark and dull and soft during capture. Don’t be tempted to brighten or sharpen it at this point. The post process will work magic on it, but only if it’s not overexposed!

Some scenes shot with available light are severely underexposed. These are basically black when projected, but can really be brought to life by the webcam. They’ll be very grainy and the color fidelity is poor, but it’s great to recover faces and details we thought were lost forever for want of those big, bright movie lights.

6) Start recording. Monitor movie on computer. Stop on Scene will stop the transfer when the scene exposure changes enough to require readjustment. Fine adjust gain during the transfer, but generally don’t touch any other settings until the scene change. When auto stop occurs, repeat step 5 and 6 for the next scene. Clips are saved as sequentially numbered AVI files. A 400 foot (30 minute) film might have 100-200 scene changes, and thus produce that many AVI files.

At the stop, I can do an instant replay with the built in player in TelecineApp. If I don’t like how something turned out, I can decrement the file number and redo it right then. If I’m not sure whether a little more exposure is better or not, I will “bracket” by running the scene twice and deleting the one I don’t prefer after post process.

7) At end of movie, use VirtualDub to delete the 2 or 3 frames at the clip changes where exposure settings were adjusted, as well as splice frames and any other garbage frames. To open the collection of files for edit, use “Open video file” for the first clip, then “Append AVI segment” to load all the subsequent clips at once. Then edit as one large movie and “Save as Segmented AVI” in “Direct Stream Copy” mode (copies original lossless compressed data without recompression). Segmented files are split into 2GB chunks, so I can archive on a FAT format external drive. This set of files is the master original, and represents the most hours of work, so it is carefully backed up. I can reprocess it as often as I like in the next step.

8) Post process with AVISynth in VirtualDub. Use Batcher to create scripts and launch VirtualDub with a command line listing all the scripts and output file names. VirtualDub SAVES the processed movie as a segmented AVI, again with HuffYuv lossless compression. I’m not keeping backups of the processed AVI, since I have the original edited transfer version, and in the future I’ll probably have a better script anyway.

9) Make DVDs with DeVeDe.

It takes time to do top quality telecine transfers. I’m spending 3 or 4 hours to scan a 400 foot reel. 2/3 of that time the machine is stopped and I’m adjusting settings for the next scene. After that, post edit takes another hour. Then I run the post process script, which requires about 4 hours to run on my laptop. This step doesn’t require any attention, but it is great to sit and watch the beautifully restored frames appear!

Here’s the system in action…

ERROR: FLV player could not be loaded.

 

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