G'day Quinten and Cameron,
I hope that this finds you well in the bleak winter of Nederlands!!! I just got an email from my ex-assistant who has decided to hibernate.......I will try to go thru your queries one by one as I am in a slight rush so forgive the brevity. I does sound to me like the missing factor in teaching lighting is to limit the number of lamps one allows a student to use. I use to run lighting workshops for DOP's at the Australian Film & TV school and the first day of the hands on workshop I would say "you only have three lights to work with......figure it out". It is amazing just of economical people get when limited this way. They actually learn to "see" the light and not the hardware which was the biggest stumbling block. So many young people ate stymied by the hardware but do not look at the light. Pity. Gradually as the students gain confidence I would ad one more lamp and then one more and then one more...you get the picture. So they actually have to make it look good with next to nothing and then learn what "adjectives" they can add to make a scene look great.

Arcs never needed "radiation suits" to change the carbons. The arc has 2 carbon rods that are connected to a D.C. electrical source and are brought into contact briefly to spark up a plasma arc. They are then separated by about an inch and a half. As the rods "burn" they wear down and a mechanism drives them together continuously to keep the arc gap constant.

HMI are arcs too but they are A.C. powered and are self contained in inside a a quartz globe that has a vacuum in it. As a result the negative air pressure, no explosions ever occurred and the need for protective suits were obviated.

Movie projectors however used to have a xenon arc globe like the HMI but under several atmospheres of pressure and it is these lamps that one had to wear protective head/eye and body armour when changing the lamp.

The project that I lit with a brute arc and mirrors was a commercial many dozens of years ago but I have to apologise and say that it never occurred to me to take photographs of what we were doing....I probably would get yelled at by the producer for NOT doing my job !!!!!

Anyway I had a look at the clips you links that you attached and while I can say for sure that they are very nice and seductive (the models help there too) I can only take wild guesses at them to figure out what they used. The B & W shots that were head to waist and head to toe are obviously a fresnel to my eyes judging by the crisp shadows. The photog obviously used a series of cutters (shadow devices) to make the head-waist shot. This picture reminds me of a technique that I have used over time by illuminating a subject with one light thru a large tracing paper frame that creates a soft ambiance and then using a razor blade to cut holes in the trace to allow direct hard light thru onto particular parts of the set/body of the model. I would suggest on the head to toe shot that the model is lit with on fresnel going thru a kookaloris (look this up on google) or something similar to "cut" up the light. It looks to me that a separate source is putting the shadows of the window sill on the background.......in both the key seems to be coming from camera right at an angle greater than that of the models gaze to create those beautiful cheekbone shadows.

With any light modifiers like the ones I described above the closer they get to the model the sharper the shadow gets so in the colour shot it looks like there is a large soft source from inside the window casting light onto the girl with her key light (again a diffused or bounced source) coming in from camera left but cut so only her head is lit by this and her body is lit from inside the window. She has almost no shadows to speak of on her face so that the key is most likely close to the lens with perhaps a touch of fill lite to make her pretty from camera right. The background seems to take care of itself with the practical lights ringing the roofline.

The B & W two shot and the head and shoulder are in the similar vein as I am sure you can figure out but with very soft shadows. This look can be achieved numerous ways from diffusion to bounce...just remember the closer the diffusion gets to the model the softer the light will be.

Anyway I must dash - hope lighting 101 was not too boring. BTW I will hold you to that beer although having lived for a bit in Prague I am partial to Czech Republic refreshments!!!!!

Stay well,
Sam