// www.chrisgavin.com: April 2013

Sunday, April 28, 2013

New Spiral

Pretty soon I'd like to try DIY processing some cine film for the first time. Processing stills film is pretty straight forward, but super 8 cine film comes in 50 foot (15 metre) lengths. This is not going to fit inside a Paterson tank and anyway, there just don't seem to be any 8mm film spirals either.

Folks seem to use Russian Lomo spiral tanks to do this, but I can't quite bring myself to send lots of good money away to buy a hunk of soviet-era bakelite from ebay. I'm guessing that many of the available tanks will be broken or have bits missing by now.

So what about designing the vector graphics for a new spiral and having it made from plastic? I would think this could be a job for a laser cutting or 3D printing service.
It might look something like this...

By my calculations this would need to be about 220mm in diameter, the channel for the film is 1mm, as are the ridges between the winds. This is a theoretical design, but who knows if this would work, or if the film could actually be loaded into such a thing? The next step will be to find a cutting/making service that could make this up for me at a reasonable price. Please comment below if you know of such a service.

Wednesday, April 24, 2013

Sumix 150M industrial camera tests again.

camera Sumix 150M, c-mount Fujinon TV zoom lens f1.8 17.5-105mm

Working late in the lab again tonight trying to see if my old Sumix 150M industrial camera can be used as a webcam (for an interview request), but it doesn't look like it can be. I bought this off ebay years ago; it's a curious little camera module for scientific/industrial uses. The Sumix 150M can shoot stills or video at up to 1280x1024 size; but only in monochrome. The Sumix camera capture software has lots of controls that you just don't get with consumer oriented gear. 

Also, the camera can take C-mount lenses and I was intrigued by the macro possibilities of the camera using some extension tubes. My goal was to try to capture frame by frame 8mm cine images from the gate of my cine projector, now that I look at it again, I wonder if that might be worth another try...

For all it's specifications though, I don't think it'll work with Skype...

Anyway, below are some test captures I made with the camera back in the day. Mostly macro photos using more and more extension tubes until I got down to the required 5mm or so image size of the 8mm film frames. I gave up with the super 8 capture experiments, but I did end up using this strange camera to shoot all of the stop motion elements for my film TXT ISLAND.

The camera is tethered to the PC by USB, so only able to take pictures of things nearby!
camera Sumix 150M, c-mount 50mm lens with extension tubes.
With a few extension tubes, macro photography becomes possible.
Some desktop clutter, surprisingly sharp.
Using rulers to show scale here.

And in we go until our image is 5mm wide.

An actual super8 frame.
Another actual super8 frame.

Sunday, April 21, 2013

I've been too busy working on something at TANDEM the last few weeks, so there's just not been any time for  DIY film-making activity at home recently.
However, when I get a little spare time I'm going to try some of this in my Super8 camera.

It's 50 feet of black and white negative film. I'm hoping to try out some DIY film processing and figured that this BW negative would be the easiest type of film to start with. Processing is similar to BW neg. stills film, with affordable chemistry at room temperature. I'm also very intrigued with the idea of 'Caffenol C' processing... Yep, that's film developer made from coffee!

Tuesday, April 02, 2013

Some Maths For Animators

Here's a little real word maths problem that's just come my way...

A stop motion animator is moving something on set by 25mm for each frame taken to create movement at a steady speed. Over the next 20 frames he wishes the movement to decelerate smoothly until a rate of 10mm per increment is achieved.
Calculate the distance the object is to be moved for each of the 20 inbetween increment positions to achieve a smooth deceleration.

Well, it's taken me a few hours over this Bank Holiday weekend, but I think I've worked out the solution for this in time for tomorrow's shoot. I've drawn on some school maths and a few Excel spreadsheet tutorials, but I've knocked up a calculator that can figure this out. i.e. Calculate the in-beteweens and print out charts (to scale) for the animator to use as fairing rulers on set. The sine wave based equation I've developed, spits out these figures for the increments.

Maybe this graph looks pretty, but it wont help the animator too much...

I've then added another column to the spreadsheet to aggregate these figures and give the actual (cumulative) measurements in mm.

I eventually found that Excel's 'Scatter Graph' could be formatted to give something like a useful chart, which when printed to the correct scale can be used on-set as a useful ruler.

So this is very basic stuff for anyone involved in the science of Motion Control, but I offer it here in the hope this might come in handy for anyone (like me) needing to work this out for themselves.

Oh, and the answer to the question is...
25, 24.9, 24.6, 24.2, 23.6, 22.8,21.9, 20.9, 19.8, 18.7, 17.5, 16.3, 15.2, 14.1, 13.1, 12.2, 11.4, 10.8, 10.4, 10.1, 10.0 (mm)