How to calculate the k (colour temp) of a combination of bulbs?

[duncangweller]

Hi All,

I am coming up to needing to replace 3 (of 6) of my t5 bulbs and I have been reading a lot about color temperature and growth rates etc etc.

However, all the info refers to 10k, 14k or 20k lighting. If you have 6 bulbs all with different color temperature then how to you come up with an overall figure? Is it just an average?

Hope someone can ear this up for me.

Ta,
Dunc

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[tang daddy]

Well it's pretty much a guess.

If you had 4 blue 2 white 16k
3 blue 2 white 1 purple 14k
4 blue 1 white 1 purple 18k
4 blue 2 purple 20k

Hope it gives you an idea......

[kien]

I really don't know the answer to this either so I'll just talk out my arse..

If it were me, I would just take an average. The bulbs are rated at a certain temperature, and since light is additive, it would stand to reason that you could average them together ? Mind you, I have no clue what a fiji purple bulb's temperature would be..

[Magickiwi]

I think a Fuji purple is 420nm.

[tang daddy]

Fuji apples.....

Fiji purple is 15k same as the Ati purple plus.

[kien]

I think a Fuji purple is 420nm.

I have no idea what the wavelength of the fiji purple bulb is either. If I recall correctly that bulb's spectral graph peaks in two places, the mid 400s and down in the mid 600s. No clue what its over all wavelength would be. I'd imagine that makes figuring its colour temperature even harder.

[kien]

Fuji apples.....

Fiji purple is 15k same as the Ati purple plus.

That makes sense. It does seem like a 15(ish)K to me.

[Aquattro]

The closer to white, more growth. More blue, better looking. Find a compromise you like looking at :)
Coming up with some random number based on averaging different bulbs is at best a WAG. Even bulbs from different manufacturers rated at the same K look different.

[kien]

Coming up with some random number based on averaging different bulbs is at best a WAG.

but this hobby is all about the numbers man! :lol:

[Aquattro]

but this hobby is all about the numbers man! :lol:

True, unfortunately :)

[tang daddy]

Never heard the term WAG, what does it stand for?

As I said in my first statement it's pretty much a guess.... But playing with different bulb combo and what my eyes perceive in colour that's what I temp looks like to me.

A quick search on urban dictionary:

1. WAG
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1038 up, 251 down
(abbv: wives and girlfriends)

A selection of overpublicised, vacuous anorexics found lurking at football matches, easily distinguised by their orange skin tone and high body plastic index, ostensibly present for the purpose of pleasuring the England football team, but in reality with the intention of being photographed obtaining fashion advice from chief WAG Mrs. Beckham in the hope that this will lead to a future appearance on "celebrity love island".

[Aquattro]

Never heard the term WAG, what does it stand for?

.

Wild A$$ Guess :)

[tang daddy]

Hahaha ok brad, I though it meant wives and Gfs.

Never ASSume anything I guess....

[gregzz4]

Hahaha ok brad, I though it meant wives and Gfs.

Never ASSume anything I guess....
So this means you took a WAG at the meaning of WAG ...

[wayner]

[quote=kien;844578]I really don't know the answer to this either so I'll just talk out my arse..


I'd like to see the video please

[kien]

I'd like to see the video please

Huh.. I didn't know that you were into that.. :lol: .. You have PM !!!

[duncangweller]

Just found a couple of really good links regarding colour temperature so I thought I would share.

http://www.atinorthamerica.com/faq.php

http://blog.reefgeek.com/2013/07/popular-t5-bulb-combos.html?m=1

Hope this helps anyone that is looking

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