I've not noticed that - so far Kino tungsten seems to be the only fluorescent tungsten worth using. Almost creamy in appearance. Unfortunately I can't really offer more than that subjective impression, but - no, not something I've noticed. I guess you could get the feeling they were muddy because they're warmer, but other than that I can't account for it.
Tungsten is technically "harder" to achieve with flos; the blue phosphors are - I assume - wider-bandwidth, which is why cooler flos tend to have better CRI. But that's something that's clearly been worked on a lot.
I'm not sure CTO will work terribly accurately on daylight flos.
You're hitting into, as Phil mentions, the fact that for your plasma based lights-- or better put phosphor based, such as Kino, LEDs etc, they ten towards blue and are pretty deficient in the red end of the spectrum. As such, even when you get them, roughly, 3200K, they're missing some wavelengths which you'd get with a comparable tungsten head-- and as such a little bit of the "life" of the colors in front of you. This is much exacerbated by anything else tungsten in the screen which gives you a "baseline" reference-- at least to my eye this seems to be the case, though I haven't really metered them. It's also a reason I tend to not use Kinos unless i have to-- and even then primarily daylight.
Something you can do to help, is to "trick" your eye a bit-- reglobing the practicals in the scene with photoflood bulbs so they go a little cooler, and perhaps using some 1/8 CTB on any tungsten heads you're using in your lighting. This will help, I find, to make the kinos as a key, pop a bit more.
I don't notice anything on the chart that would suggest towards a magenta/pink shift in the 3200k. Although the 2900k tube looks interesting, with a slight spike just below 600nm (which is maybe why it looks more pleasing Satsuki?)
Adrian, I think your technique makes sense, and I should try this sometime on a future project.
The pictures show the CCT, CRI and CIE 1931 coordinates. In this case the K32 bulbs were a bit closer to target than the K55 bulbs in terms of CCT an CRI - but that's not the complete story.
In theory a D55 (5503K) illuminant should have a CIE 1931 coordinate of (x,y)=(0.332,0.347). The K55 bulb showed a reading of (x,y)=(0.308,0.315), which is much more blue. The bulb is performing much closer to a F1 (fluorescent daylight) standard illuminant.
Since I don't have a good reference for the color coordinates for 3200K, nor time to calculate it, I'll reference a 3000K illuminant. This is pretty close to the CCT the MK350 spectrometer said the K32 bulb is anyway. That should have a CIE 1931 coordinate of about (x,y)=(0.25, 0.35), whereas the bulb measures (0.422,0.382) which is WAY more green. It's much closer to an F12 (3000K fluorescent) standard illuminant.
If you look up "CIE 1931" and "D55 standard illuminant" on Google the Wikipedia pages are actually quite good. The half-ellipsoidal chart should immediately pop up when you type in "CIE 1931". That will show you how (x,y) coordinates correlate to colors.
On the way to work today, I was thinking about the K55 Kiva tube measurement being 6942K. If we consider the nearest camera setting of 6900K, that's a CIE 1931 of (x,y)=(0.308,0.318). In that case the K55 tube seems to rate really well as a 6900K source. I wonder where Kino-Flo got their K55 (seeming to allude to 5500K) name from? It would be interesting to hear their comments if they have a representative on this forum.
I have never had an issue with the 4 bank 4 ft kinos. I have had issues with the Diva's turning magenta. As others have stated, there are certain wavelengths missing from any phosphor light source. The questions becomes, how offensive is it? In the real world we see a wide variety of light sources in all colors, textures in a variety of intensities coming from all directions. When lighting, we concern ourselves with supporting the material being shot with the visuals. So, the question shouldn't be as much is the source a true 3200k but rather does the source work for the intent of the scene being shot. Does it support the emotional moment that the piece is trying to convey to the viewer? if the source is producing a magenta light that pulls the viewer out of the moment or doesn't work for the desired look, then it should be gelled or otherwise corrected.
Many famous cinematographers have been commenting lately that they fear so many new camera people have forgot how to light - how to use their eyes to light something that supports the story. Some blame this on the massive attention to new technology and being absolutely exact while others blame this on the high sensitivity cameras that can get an acceptable image with no lighting. While we need to have reliable units and we have to pay attention to their kelvin degrees, the end judge should be the human eye and the feeling the image generates.
Many famous cinematographers have been commenting lately that they fear so many new camera people have forgot how to light - how to use their eyes to light something that supports the story. Some blame .... blame this on the high sensitivity cameras that can get an acceptable image with no lighting.
I agree 100%. That you can get a serviceable image with an Alexa with available light doesn’t mean that you don’t need to light a shot. The problem with working with available light is that it is not always what you want for a scene. This trend towards making pictures “without too much help from the electric department” is IMO troubling because the DOP is giving up authorship of the image. If his/her options are limited to what the great Gaffer in the sky happens to provide that day, the creative options are limited. And if by chance the available light does happen to coincide with what is creatively desired, it will invariably change in the course of the production, leaving the editor with a continuity nightmare. IMO, it is better to tame the natural daylight, and use lights to create a consistent and aesthetically appropriate look that models your set and talent as you wish, than to limit yourself to what your dealt that day and take your chances.
Guy Holt, Gaffer, SceenLight & Grip, Lighting and Grip Rental in Boston.