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Robert Hart

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Posts posted by Robert Hart

  1. It was not uncommon for wow and flutter to occur in syndicated music under commentary of 16mm documentary films. The fidelity of the commentary is really quite good for 16mm. Because wow and flutter occurred in film projectors as well, people may have cared less about it and let it through.

    If you still have the film, perhaps take a scan of the image and soundtrack and use AEO Lite to reconstruct the sound track. That should tell you if the film's linear speed was not stable through the sound reproducer of the Lasergraphics machine.

  2. On 3/14/2024 at 7:41 AM, Perry Paolantonio said:

    I saw the parts list for a Universal build. Someone posted it on facebook. the machine consists mostly of screws and springs and off the shelf bits. Inexplicably, several copper roofing nails too.

    The bankruptcy filing lists IP and patents as having a value of about $100. I don't think there's a single thing in this machine that's especially innovative or special, or patentable.

    It is not the parts themselves which may or may not be all store-bought but the sum of all the parts and the application they are directed to which form a registerable design. 

  3. It is rather a pity. With careful fine adjustment, the transport and frame triggering can be very stable. Like all scanners, it can become a troubled child when old and damaged film is scanned. Mechanical reliability related to the original electromechanical unidirectional clutches and the first in-house purely mechanical replacement clutch which also failed in service brought the enterprise low. 

    One hopes that competing manufacturers do not harvest the proprietary IP from the bankruptcy administrator just for the anti-competitive purpose of burying it. If owner-users want to preserve some level of product support, then they may need to bite the bullet and club together to bid for the IP, proprietary registered circuit/hardware designs and CAD files. The basic system has good bones but some achilles heels as well.

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  4. An option out of left field might be to find an old groundglass-based 35mm film-image emulator like a Letus Extreme or a P+S Technik Mini35-400. They used to come with rails, tripod mount bases and bridge-plates. It would require much adaption and you likely would need to use a 75mm prime lens.

    You could then use stills 35mm film lenses in Nikon, Canon or even PL-Mount in some instances. You would still need to crop top and bottom of frame or add an anamorphic adaptor for a cinemascope look. Your depth of field will be quite shallow. That was often a signature of users who went for razor thin depths of field not because they should but because they could.

    A Mini35-400 resolves between the old standard definition TV and JVC's flavour of HDV. A Letus35 Extreme can be tricked up to resolve a little better and if significantly modified achieve near to 35mm full frame and 2K. 

    Your would lose about 1/3 to 2/3 f-stop of light and with tighter apertures than f5.6, some nasty artefacts begin to appear.

    I tried it for kicks with a CP16 16mm camera with this rather unscientific test and a sort end of 16mm film,

    The letters DTC mean direct to camera, that is without the groundglass adaptor in the optical path.

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  5. If you dry-run the Bolex without film going through, please do not run it until it stops. In an unloaded state, the inertia in the film transport, especially at high frame rates may drive the spring and damage it. 

    When you button off, make the movement quick and decisive. If the run button is released slowly, there will be a clattering sound and there will be several light frames. The mechanism inside can cope with it but it is best not to have that happening. 

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  6. I have had the piece of aluminium stock sitting in a 4-jaw lathe chuck to make the heatsink. To restore back-tension which I had backed off as much as I could when using the pressure plate for 16mm film, for an unexpected 8mm task, I resorted to some primitive bogan engineering with a piece of foam stuck to a piece of flatbar with a felt rubbing strip and around it.

    I carefully chose the book thicknesses to stack to stop the flatbar from moving across but add no extra pressure. It was that or pull the outfeed motor assembly out of the cabinet and upset my careful 16mm back-tension adjustments made when setting up the pressure plate. Extreme care is needed to avoid overloading the take-up motor/transmission and the old style electro-mechanical clutch.

    Andrew Wise and myself have had separate notions of how to implement a mechanical load-sensing arrangement for constant back-tension with a swingarm and brake band around a hub similar to old analogue audio recorders. The challenge is to make it fit around the exiting hardware and play nice without requiring things to be cut and changed. 

    RETRO HEATSINK.jpg

    RETRO BACKTENSION.jpg

  7. This is the COB LED that Dan Baxter pointed me to. 

    https://store.yujiintl.com/collections/led-cobs/products/yujileds-cri-95-50w-cob-led-3200k-5600k-400l

    This is the setup for the COB LED lamp powered and controlled independently of the Scanner's own electricals. My own arrangement was for convenience and avoidance of an extra set of cables for some fool like me to hang a stray toe in with a double bonus of damaging the cord and stretching me senseless on the floor.

    For a heatsink I have a temporary piece of finned heatsink trimmed down to fit. I intended to replace it with a more robust heatsink styled after the one in the accompanying image. It appears to have been made up from broad and narrow washers stacked with two long machine screws to hold them all together. My guess is that there will be thermal compound in between each of the pieces and under the COB LED. The heatsink would have to be made for you as a custom job. 

    I think you will find that RS Components will have the LED driver box and the 50W laptop powerpack. For a pot, I do not know the values. I just grabbed one out of a parts box I had handy and used that before using the control source from the mainboard of the scanner. 

    5igTPhs.jpg

  8. Following some generous advice from other contributors here, I made some improvements.

    To upgrade the lamp will require another power source for the lamp driver. I had a few old PCs which had laid down but had perfectly good power supplies. Some can be tricked into supplying power by linking a switching circuit that the motherboard of a PC normally energises. Other cannot without some serious innovation beyond my meagre abilities.

    I used one to supply power both to the scanner and to an LED driver. I installed it within the rear of the cabinet with suitable venting for it. Be aware that installing anything high voltage which can incinerate itself when it fails is not a good thing to have within wooden cabinetry. The manufacturer of the Retroscan sensibly avoids that risk by using a remote power supply. 

    Whilst I originally used a separate pot to control the light level, I found that I could use the controller output from the scanner's main board itself. I did not draw power for the LED driver from the main board. 

    I bought and installed a 4K FLIR camera and use the Spinnaker Spinview application. The camera is not seen by the Alteraware app which is custom for the 2K scanner. For my capture PCs limitations and the USB3 connection, the frame rate has to be reduced to below about 9FPS. The camera seems to present its full 4K dose of sensor data even if the sensor is windowed. 

    The speed controller was going to be a harder nut to crack. An innovator with the Mark 2 in the US suggested a simpler solution, that of adding a powered motor controller in series on the power line to the take-up drive motor. That has worked fine but there is a frame rate increase as the wind diameter on the take-up reel builds. 

    The machine is no longer a set and forget proposition but requires monitoring and several adjustments of the transport speed of the film during a scan run. 

    For mildly shrunken and warped/cupped film, I found that a pressure plate which spans the fixed guides and attention to the back-tension on the film is adequate to maintain the film at the light pin's adjusted focal plane.

    For the 35mm film, smaller diameter rollers each side of the "gate" are desirable as the film is bent acutely at the fixed guides with the larger rollers. The downside of smaller rollers is less inertia therefore slightly less stability of the film speed through the gate. 

    A workaround for mildly warped film is to shim the outfeed roller so that a lateral tension is applied downstream of the outfeeding fixed guide and tends to destress the film edge under the light pin and move the ripple to the opposite edge.

    For film which has been cleaned too many times and the emulsion face has become less reflective, it may be necessary to flip the film during a rewind so that the reflective base is seen by the light pin. 

    With care, film can capture nearly if not as steadily through the Retroscan as any other but of course on-the-fly electronic steadying offered by other products is not available. Things fall in a heap when a splice or sprocket hole damage visits and passes through. Some things you just have to be prepared to pay for. 


     

  9. You did very well to get those greens and blues back. As for stabilisation in Resolve, I have never been able to make it work on sprocket hole edges. I think the horsepower of my PC is the issue. It will analyse about five seconds of footage then gives up.

    It would not be impossible to build a proper wetgate for the Retroscan as the geometry of the film path is favourable. However, the lightpin edge detector would have to be moved as it relies on surface reflectance which is not available from the film within the wetgate tank.

    The further the light pin is away from the actual film "gate", the more disrupted the sequence of images becomes as splice interference occurs much deeper into the sequence of frames after the splice goes though the gate.

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  10. Here is a link to a test with surface wetted film which worked better when the shiny base of the film was presented to the light pin sensor. Sprocket hole registration is still not as steady as when film is dry. You will observe some patching and banding from earlier successive dips of the film when the material had not flashed off before the film wound onto the reel. The effect of cupping was reduced when the film went over shiny side up.
     

     

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  11.  It is not particularly newsworthy or an innovation but I tried making a dip-tank for surface-wetted scratch reduction when scanning 15mm or 8mm film with a Retroscan Mark 2. I was using isopropyl alcohol of claimed 100% purity. It did work but also tended to destabilise the sprocket hole registration.

    At more than about 7FPS with 16mm, the material was not drying off before it entered the take-up wind. It is also not benign when it comes to film emulsion. After something like about ten tests with some old print film, I discovered that the base material was cupping and the glazed surface of the emulsion was becoming opaque to the light pin edge detector.

    I guess Film Fabriek experimented with full immersion, discovering the pitfalls before going with wicking pads to coat the film more sparingly. Once the emulsion surface has become dull, the film has to be flipped so that the shiny surface of the film base faces the light pin and edges of tape splices do not set off false triggers. In this instance, I was running the film from right to left on the top of the reels to present the shiny base to the light pin detector.

    The small knob under the dip-tank is not related to the dip-tank but a speed controller which is not original manufacturer's equipment. My PC hardware and the USB path does ot cope well with the frame rate when capturing with a 4K FLIR camera.

     

    DIPTANK.jpg

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  12. Sorry about that. A slip of the fingers while writing the post. 

    I bought in the machine to digitise my own personally filmed archive with a view to either selling the machine after the scans were done or taking jobs for customers if that turned out to be worthwhile. Among the films which were being discarded were about three Toyota Echo loads of 1970s-era nightly news film assemblies on 16mm. The film rolls had been sorted through and the most relevant items had been taken and assembled into another smaller archive by the TV station. The rolls I salvaged went to anther archive. What remains with me are a few rolls of out-takes from documentaries. The QANTAS roll was gathered by a documentary maker for inclusion in a documentary about koalas. So far as I know, the project was completed but was never broadcast. I do not have the assembly/edit but some of the out-takes.

    The machine I am using is a Retroscan Universal Mark II.

    A lot of what was culled from the new archive was reports from overseas which had been kined from live news. This was one such.
     

     

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  13. John OBrien. It may be as simple as cost-driven fast but unthorough expediency, reliant upon how much degradation of product quality the marketplace will bear. If everyone else is driving the cost down, no single entity competing in the same genre may be able to afford not to in the end. A bland factory sameness may be what is driving the decline in streaming subscription as much as the post-COVID reduction in a family's "discretionary spend". Finding the gems amid the dross may be requiring too much effort and too many subscriptions. The "consumer" may be taking the game off the table as too hard.

  14. Further to my comments above, the light leak looks like normal edge flaring from light passing into the gap of a daylight spool because after a while it goes away. If you inspect the film by eyeballing the film itself, you may observe similar leak flares on the sprocket side of the film. 

    Another cause of variation of focus may be the three lens turret if you camera has one not being locked down. From memory, there should be a little dummy plug which screws into the body through the upper lens hole. If that is not fitted or loose, a heavy lens may droop downwards slightly and cause varying focus between the upper edge and lower edge. 

    Gently lift the front of the lens and check that the turret disk is not moving, closing and opening a thin gap at the top between the turret disk and the front of the camera body. If looking through the viewfinder when doing this, you may observe focal shifts.

  15. I second Dom's assessment of the pressure plate. I cannot now remember if the Bolex gate has rails of a flat surface. If there are rails and the extended image side rail has been milled narrower, then the pressure plate is likely to be pressing inwards of the rail edge and bulging the film towards the lens.

    Another cause may be the edge guides of the gate which hold the film steady from weaving. I cannot recall if they are adjustable. If so, then they may have been set too close to each other and causing the film to cup out of focus and also lift the pressure plate. The momentary increases in the defect suggest that film shape memory from being parked around a sprocket may be lifting the pressure plate slightly higher passing through. 

    From memory, the pressure plate on my RX5 was black plastic and there was considerable clearance between the side rails and the pressure plate edges. The variations may be the film tension through the gate buckling the film a little more until the motion stabilises.

    I had a bulge problem with a CP16 caused by an edge guide which had become skewed during reassembly after some maintenance. It was never apparent until the first time a shot indoors in low light with fully wide aperture and there it was as plain as day. Lost a critical 100ft roll to it.

    The light leak may be from two causes :

    Damage to a little plastic bloop-lamp housing on the bottom right of the camera as viewed from the front.

    Light passing around the very edge of the shutter disk which may not be of quite wide enough diameter. If the light is rebounding from newly dressed metal in the gate aperture, painting that edge with lens black or a sharpie may be a temporary fix. 

    A fix is realistically the province of a camera tech to sort out. 

  16. Pulldown is taking off before the shutter closes. If there is a helical drive gear for the shutter, a thrust washer may have worn allowing the shutter disk to move slightly on the spiral gears and cause the shutter to become late. If your camera is a reflex type, chances are the collimation of the film plane and groundglass viewfinder is also off.

  17. My sense is to respect the lenses and have the work done by professionals who know what they are doing. Before I knew their intrinsic worth, I de-fungussed  two Speed Panchro Series II lenses. They had been assessed as uneconomic to repair and were a gift. The 50mm was fairly straightforward but one of the internal optics had a little penetration into the glass. The front coating cleaned up well enough.

    The 75mm was a basket case with small but noticeable scratches on the front element from careless cleaning and one of the internal elements had penetrating fungus erosion of the glass itself. I made a sort of conforming mould and polished the eroded glass with cerium oxide. By more dumb luck than good judgement it worked. On reflection and from reading I have done since, it was something of a minor miracle that I did not destroy the figure of the element.

    Both lenses ended up flarey, the 75mm more so. Outfits like P+S Technik apparently polish and recoat the glass of the lenses they modernise. This is of course a costly exercise.

  18. If there is extreme governor hunt (jerking) and flashing of highlights during slow pans (lesser surges of speed), chances may be that oil has got onto the little leather governor shoes and may even have become gelled. Their normal operating state is to be completely dry. As the spring winds down and its power diminishes, the normally fine adjustments by the governor may have become coarsened by contaminated shoes momentarily gripping in the bell then being suddenly released as the centrifugal force collapses. The only cure is servicing by a proper camera tech. However please take heed of folk properly knowledged about the Bolex gizzards than I am. 

  19. If your drive spring is weary, you may only get about 15 seconds before the frame rate drops off the governor. 

    A quick and dirty method of checking the spring is to load a roll of junk film. set the governor frame rate to whatever your local power supply frequency is, 50Hz for PAL TV countries and 30Hz for the US and many others. Place your camera under an old-school flourescent tube lamp and watch the frame counter dial on the side of the camera.

    You should be able to just see the marks as they move. They may hold steady or creep. Any speed change will be apparent as the creep forward of backward will alter. You can also take the lens out of the Bolex and through the lens mount opening, view the shutter blade whilst film is pulling through an older-non-reflex camera. 

    The screen light from old-school CRT television sets was also good for checking the camera governor. New LCD televisions/monitors do not flicker as much.

    If you have a video-camera which has a high shutter speed, you can use that to view the frame counter though a close-up lens/macro by setting the governor to as near to the video frame rate as you can get, ie., 25P, 24P, 30P.

    I used a similar hack to set the governor speed on a generator.

    Shooting with the parallax-adjustable side-finder in well lit conditions is not hard but requires the discipline of a mental check list every time you use the camera. 

    As long as you are patient, you can use the eyepiece out of an old pair of binoculars to view the groundglass screen of the upper view port which you use by rotating the lens turret to bring the selected lens into view. Take care to press the lens turret disk rearwards. Sometimes the weight of lenses pulls the turret disk forwards and the focus will then be off.

    This method is fraught with possibilities to waste film as the lens aperture has to be opened wide for accurate focus and to be able to see anything on the dull groundglass. 

    A few folk have made video-split hacks with small CCTV security cameras, 50mm lens and about ten 5mm CS- to C-Mount spacers stacked behind the 50mm lens and a bodged spacer between the front of the lens and that upper viewport. this means adding wires, power supply and a viewing monitor which rather defeats the agility of the bare camera. 

  20. The camera itself most likely needs attention and is a task that only a competent camera tech can undertake with confidence.

    Any mismatch between the viewed groundglass texture and the film surface will be more apparent with wide-angle lenses. The wider the aperture, the more apparent the focus issue will be.

    The adjustable eyepiece dioptre itself which enables the eye to focus on the groundglass screen is not the issue. 

    The likely causes of your problem may be :- 

    the position of the textured surface of the groundglass may be incorrect relative to the film plane. 
    the rotating shutter mirror surface may no longer be correctly positioned due to wear of a bearing surface. 

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