Bob,

Some very minor comments on an interesting article:

How about mentioning the Minolta Colormeter II? There are plenty of them available second-hand for around $200 and they are OK for continuous light.

You might mention that 3400 K lamps are also known by as P1 and 3200 K as P2. By the way, kelvin is written without a capital K (in accordance with SI convention for the names of units), and the abbreviation is 'K', not 'K'. The SI name for mired is 'reciprocal megakelvin', if it matters.

One convention that I'm aware of refers to CT and CC filters. CT being the ones for adjusting colour temperature and CC for colour compensation. CC filters are in RGB and CMY only: typical Wratten-style designations are CC20M and CC025R for example. Wratten 80 and 85 series are called 'conversion' filters and the 81 and 82 series are called 'balancing' filters by Kodak.

With still film I use my colour meter for fluorescent lights more than for incandescent sources - which can often be guessed at quite well. I carry CC10M and CC20M filters - my preference is almost always to under-correct so that the character of the lighting is maintained.

Your examples of colour temperature of sources doesn't cover practical indoor sources (ie general service lamps). Maybe it would be worth adding approximate values:

200 W GS lamp: 3000 K
100 W GS lamp: 2900 K
60 to 75 W GS lamp: 2800 K
30 to 40 W GS lamp: 2600 K
candle: 1400 K

Passing thought: is it worth mentioning that non-incandescent sources can have a correlated colour temperature?


Just out of interest, does anyone make Type A tungsten film for still cameras nowadays? As well as mentioning Type F, you may also wish to mention Type G Ektachrome - which was balanced for about 4200 K as I recall, and which is probably still being used because it isn't so long since it was discontinued.

Best,
Helen
PS I'd take issue with you about digital cameras not needing CT or CC filters at all - but that's not for this forum.