For what it is worth, in APUG's world, I am a street photographer so I use ambient light when shooting. I am also however a Gaffer/Chief Lighting Technician on motion pictures (35 years now) and use the whole gamut so to speak. I concur with Csurrier having a selection of light modification devices on hand to trim the shapes and/or to soften the output of fresnels. Examples of cutters/flags/nets/kookuloris/wires/bounces/ diffusions are available in images all over the net and can be home-made very inexpensively. Gels for accents or colour temp modification is usually a purchasable item but can he had at film production houses. Gels also last "forever" depending on how they are treated. I notice that you are from A'dam and I have used Het Licht once or twice so they may have some off cuts that they can throw your way instead of throwing in the rubbish bin. Because I am a very "old fart" I have aesthetic tendencies leaning towards bare fresnel lighting....this IS somewhat old fashioned by todays standards but I have noticed that a "retro" look is now coming back into portraiture. There are many picture folios of the old style "noir" lighting looks from Hollywood films and portraitists of yesterday available at the usual internet book places.Just my humble opinion but it's not the light source that is an issue (HMI v. tungsten v. flash) in portraiture but the last thing that affects the light before it hits the subject (be it a naked fres or a frame of diffusion or a bounce board – in pecking order from hard to soft). HMI's produce an extraordinary amount of light for the given current pulled from the electricity source. They are daylight balanced (5500 - 6000 K) and have a CRI (Colour Rendition Index - i.e. the ability to make a red apple appear the proper red) of 95+ (100 being perfect). They are great if you have the $$ (hire or purchase) and the ability to colour balance either the lamp or the camera or the film stock to daylight. I do think that the important concept here though is the placement of the key (lamp height and azimuth) to the sitter. Next decision should be various other lamps to accent – fill, kicker, back, set and other lights as deemed necessary. One last thought though and this again may sound superfluous but many time in my life it was NOT how much light you used to illuminate a subject BUT rather how much you took away with judicious cutting ........ I have seen incredible lighting with just one source but cut up in such a way as to make a breath taking picture. Anyway sorry to all posters and readers fro rambling on like this - can't help being old. I am not sure (like Csurrier) whether I have answered your question or if in fact helped you at all but hey, there ya go! Good luck and cheers for now, Sam