Marc Roessler

Hi guys, while browsing through the catalogs of European (German, to be precise) light equipment suppliers I noticed that professional 230V halogen lamps are increasingly hard to find... it almost seems like 240V lamps are the new standard? Does anyone know why? Mains voltage (single phase/phase to neutral) in Europe is still 230V +/-10%, so why are vendors increasingly introducing 240V bulbs? (Or is the manufacturers?) 240V lamps in a 230V (+/-23V) grid are very inconvenient... It's easy to dim down a 230V lamp if voltage is too high. Boosting voltage to 240V is not so simple in comparison... Even assuming mains may be (if we're lucky) at 240V (well within the tolerance range): when pulling a few amps (as is typical at a film set), voltage typically will go down quite a bit due to line losses, moving away from 240 Volts (and making the lamps warmer)... Am I missing anything here? Cheers, Marc

Polyester (aka Estar) base also is problematic with regard to light piping. Not so much of a problem for print film in the lab, but it is a somewhat of a problem for 100' daylight rolls and even when loading 16mm two-chamber mags like Arri or Aaton. The light bounces around within the base and is carried far into the roll, much further than with triacetate stock.

Simon, are you sure about the 1.33 for 35mm? (Or was this only with regard to 16mm formats? I wasn't quite sure from what you wrote.) Torkell Saetervadet's (excellent) book "The Advanced Projection Manual" (I have the 2006 release) says that after 1.33 silent and 1.19 movietone the aperture was brought to 1.37 by AMPAS. The reason given was that theaters got bigger, with that the down-angle tilt increased, and thus also the sideways cropping due to keystoning increased. To wind up with (on average) 1.33 again on the screen, the actual aperture was defined as 1.37. So if one wants to see it without any cropping, one would use a 1.37 aperture? All the best, Marc

My experience is, when you're in the changing bag (or a dark room) you need all the tactility you can get, because it's all you got when working in the dark. I'd not be comfortable loading with gloves, since there is a higher risk of missing when something goes wrong in the film path. Keep your changing bag and mags fastidiously clean, and only work with clean (and thoroughly dry!) hands. A few small wet (not dripping wet) towels in plastic bags do a good job for cleaning your hands when on location. Roll for 2 seconds after a mag change before doing the first take and you should be fine. All the best, Marc

It's ARRI's most sold (film) camera, so used ones were/are quite easy to get. The cameras were quite popular as crash cameras. Note it doesn't have a viewfinder and a different lens mount. I think the mechanism is a bit different from the 35-IIc, so in case you get one for parts check with James which parts are actually usable.

Yes indeed! I was trying to address Ville. Sorry about the mixup.

Hi Rob, chiming in a bit late, not sure if you already shot your film. About the Cine Mobil 1200, it's a german made HMI from the (as far as I know) 80s. I've seen them on numerous Indie film sets in Germany in the 90s and 00s as they are usually available for rent cheap. The ballast tends to run a bit hot after a few hours, some of them started smelling a bit like melting varnish. The ballast is a big mass of iron, so they take some time to cool down again. The case has ventilation holes on all four sides, so blowing a small fan into it can improve things if you run into that problem. If the ballast is humming/buzzing, sometimes it is just the main relay buzzing. The relay is mounted just beneath the top cover. Sometimes giving it a small hit by setting the ballast down to the floor hard (not that hard!) while operating can cure things. It's not an ARRI robustness wise, but it works. Kind regards, Marc

Hi guys, I'm currently struggling with Resolve Lite.. my input is 10 bit log DPX from a 16mm film scan. The film has been over-exposed 1 stop (old stock, EXR100) to compensate for elevated base fog. I want to go to rec709 using Resolve.. but the results I get from Resolve look unbelievably ugly. For comparison, I opened the DPX sequence using an old version of Pomfort Silverstack (that was still tailored towards DPX), using the Silverstack integrated Log-Lin 1.8 Gamma LUT. I use the R/G/B settings to "print the neg down" again to normal exposure. It looks very nice (see attached image). Now I'm trying to pipe this through Resolve.. no matter what I do, the image always looks harsh and very un-organic (see attached image.. strange colors, apparent grain, strange highlight handling). It almost looks like a partly ENR'ed (bleach bypass) print! I tried using several different LUTs (the integrated ones as well as the print LUTs LC3DL_Kodak2383_log2hd_*.cube LUTS available here http://cbkmrks.blogspot.de/2013/01/download-free-davinci-resolve-film.html ..). I tried go get better results by spending lots of time grading the material, but I get nowhere near what I get from Silverstack out of the box (plus R/G/B adjustment), as you can see from the attached image. Unfortunately, their LUTs are not known. How do you other guys approach this? Kind regards, Marc

I just bought a 1970s made Minolta Color Meter off ebay (the one with the two rotating scales). It’s a beauty. Does anybody have more detailed info on those? I found a manual as PDF but it’s not very service-centric. There are 11 (!) little trimpots under a service opening at the back, plus two or three more behind the silicon diode PCB. Tracing some of the wires I have an idea about the functions of 3 or 4 or the trimpots, but especially how the cyan/magenta balance is setup is still quite unclear to me. Any input is very much welcome. Kind regards, Marc

Thanks Phil, good point! That's also a good possible explanation what LEE's UV filters are for: for filtering that last little bit of long wave UV that makes UV active materials glow.

Hi, I'm curently restoring a second hand 1200W HMI (open face) that I bought. It has the protection glass in place, but testing it it appeared to me that white paper that is hit by its light seemed to have some bluish glow. Knowing some papers have UV active whiteners, for checking I added a LEE UV filter, and lo and behold the blue glow of the paper is gone! This means this HMI puts out quite some UV even with its glass in place! Now the question is: is this still within the normal range or should I replace the glass? How do I find out if it is within the normal range? I've used HMIs a few times (also bigger ones, 4K fresnel) but never noticed this effect with other HMIs. Or is some UV to be expected? How much? Kind regards, Marc

Hi guys, while taking photos of a scenery illuminated with a HMI lamp (magnetic ballast) I noticed the following: #1 each picture has a different brightness; kind of expected, since the camera shutter is not synchronized with the mains frequency (50 Hz here, i.e. 100 Hz light pulses) #2 Every picture has a different color tint to it. The effect is very obvious, color casts vary between white, greenish/yellowish, blueish and magenta/pink. The digital camera was set to a fixed color temperature (daylight), so this is no "pumping" effect of an auto white balance or anything. So my question is: Does HMI light color really vary over one cycle of mains frequency when using magnetic ballasts? Or are my lamps/ballasts damaged? I tried this with two different HMI fixtures/lamps (with new lamps), same behavior for both of them. Followup Question: why doesn't this have an effect on color uniformity with digital (non global shutter) or film cameras with mirror shutter? After all, different parts of the image are exposed at different times, right? Or does it have an effect sometimes? KInd regards, Marc

"way below 1.0" I meant to say

Concerning the current increase when choosing different taps at the transformer, it increases linear as you compensate for the drop across the cable. This is a few amperes. But they can make a difference if you are near the circuit's limit and run it for more than a few minutes. Transformer losses are little, that's true - just what I wrote. But I was talking about cos phi, i.e. power factor of the iron transformer. What's the cos phi of your transformer? Unless it is 1, you can't make full use of the supplied current (VA vs. Watts). For the transformers I commonly encounter, power factor often is way 1.0. I'll not go into the details because I simply don't have the time to do so. For that particular setup that started the conversation (one private owned 2K softlight) I'll stand by my preference for proper cabling and 240V globes. :) Kind regards, Marc

Maybe this came across wrong, I'm not putting your system down. I was just saying that it comes with its own advantages and drawbacks, and given those for the particular setup presented I felt (and still feel) it'd not be the right choice. Let's recall: it's about a 2kW Softlite! Lamping with 240V globes and getting proper cabling so to keep cable losses low isn't a problem really here. Buying and lugging around an iron core transformer is, to me at least. Kind regards, Marc