This is from the Post ask your questions here.
https://www.modelmayhem.com/p.php?thread_id=252362

This is an open thread for all to voice answers in  the locked thread is listed here



ok question:

And why if flash is daylight balanced do they put tungsten modeling lights in ? should I be using HMI's instead.

If you are using strobe they are overpowering the modeling light so what temperature it is in not relevant unless you are dragging the shutter slow enough or shooting at a EV that allows the modeling lights to have an impact on the overall exposure.  If that is the case I may question why you are using the strobe at all and if you understand the nature of mixed lighting and subsequent color temperature shifts that result.  Its not right or wrong but rather dependent on the purpose and outcome desired.

HMI's are Hydrargyrum Medium-Arc Iodide, which uses an arc lamp instead of an incandescent bulb to produce light.  I am going to assume you mean HID  which are high intensity discharge in general and range more than just HMI, they all tend to be produced to a color temperature standard of daylight rather than the warmer tungsten and are more efficient usually 2 to 5 times more so.  This makes them more practical and also makes them far more expensive and less practical in use, they are most often ballast driven. 

They would be a good mix for daylight or strobe as the color temp are very close, they are more expensive and may be less practical, and strobes can outpower them on a dollar per watt second scale. 

The decision to use HMI or HID lights is one of personal preference and taste and cannot be answered by anyone but you depending on your desired outcome and working style.