Color Temperature Difference

[Michael Williams]

I have question about color temperature differences. Is the difference between a 2900k practical bulb and a 3200k movie light that different? The reason I ask is because I shot something on 16mm. We used some 2900k bulbs we bought from film tools to put in certain areas of a room and lit our talent with 650's (no gel) near those practical lights to accent them. To my eye I really did not see a difference on the skin tone or area being lit (of one light being more warm than the other). It was Expression 500 and I know film sees different from our eyes, but is a 300k temperature difference really going to create problems?

[Adrian Sierkowski]

It depends how you define "problem." The K scale is a bit odd in that as you move up it, the visible difference between 2 color temperatures shirts, e/g 5900K and 5600K are a lot close together in look than 3200K and 2900K.

This is why we use MIRED scales often. http://en.wikipedia.org/wiki/Mired

 

For your own problem your 2900s will look warmer than the 3200s. I personally dont think this is a bad thing really, as household bulbs always look a bit warm to my eye. Now, in your telecine you could power window winds, or split the difference in color balance, so your 3200 will cool off a bit as will your 2900s. I don't think it'll be too bad, really. But you'll just have to wait and see.

i forget the exact gel, might be straw, that you can add to a 3200K bulb to warm 'er up to match households. For myself, I normally leave the 2 alone, as I said.

[Michael Williams]

Thanks. I agree and wanted my practicals to go a bit warmer than what I was keying my actors with. My concern was about the mired shift and if I was going to have a odd look with two different kelvin temps mixed as one.

 

It depends how you define "problem." The K scale is a bit odd in that as you move up it, the visible difference between 2 color temperatures shirts, e/g 5900K and 5600K are a lot close together in look than 3200K and 2900K.

This is why we use MIRED scales often. http://en.wikipedia.org/wiki/Mired

 

For your own problem your 2900s will look warmer than the 3200s. I personally dont think this is a bad thing really, as household bulbs always look a bit warm to my eye. Now, in your telecine you could power window winds, or split the difference in color balance, so your 3200 will cool off a bit as will your 2900s. I don't think it'll be too bad, really. But you'll just have to wait and see.

i forget the exact gel, might be straw, that you can add to a 3200K bulb to warm 'er up to match households. For myself, I normally leave the 2 alone, as I said.

[Brian Drysdale]

Thanks. I agree and wanted my practicals to go a bit warmer than what I was keying my actors with. My concern was about the mired shift and if I was going to have a odd look with two different kelvin temps mixed as one.

 

If it causes you a problem, a 1/4 CTO on your film lights should sort any differences.

[Saul Rodgar]

Also, (while it is good to know how to color match light sources) keep in mind that different color temperatures occur naturally around us constantly. So wometimes the same (consistent) color temperature is desired within any given scene, sometimes if may just look too boring, especially if in every scene everything always match color temp wise. ;)