Matching north light with fluorescent bulbs

[Tony Pro]

[QUOTE=Marvin Mattelson]
In addition I've never seen any lights that are better.

Here is the description from their site:

Lumichrome

[Marvin Mattelson]

The 5000k bulbs do not match the color of the light coming in from my north window. What can I say? The 6500k bulbs, on the other hand, are a perfect match. I love painting under these bulbs. The 6500k bulbs are used in the textile industry where color matching is hyper critical. Artists have always sought the cooler light of the norther exposure. Also, the CRI of the 6500k bulbs is higher than the 5000k ones. 5000k is a standard in the printing industry which is why they suggest these for artists.

I find that the manufacturers of bulbs (or anything for that matter) are usually wrong when suggesting what is right for the artist. I'd rather take the word of an actual real live artist myself. For example Soltek recommends 3500k bulbs which are ridiculously yellow-orange. They've convinced galleries and museums of the superiority of their bulbs. You can't even see the color of the paintings, it's so distorted. The Ott 5000k bulbs appear very green to me. Caveat emptor!

When all is said and done, you might prefer the 5000k.

[Tony Pro]

I definatley agree with you about the OTT lite... they are terrible. I bought one to use for a model stand to simulate cool window light for my classes and all I get is green. It's terrible.

Originally Posted by Marvin Mattelson

The 5000k bulbs do not match the color of the light coming in from my north window. What can I say? The 6500k bulbs, on the other hand, are a perfect match. I love painting under these bulbs. The 6500k bulbs are used in the textile industry where color matching is hyper critical. Artists have always sought the cooler light of the norther exposure. Also, the CRI of the 6500k bulbs is higher than the 5000k ones. 5000k is a standard in the printing industry which is why they suggest these for artists.

I find that the manufacturers of bulbs (or anything for that matter) are usually wrong when suggesting what is right for the artist. I'd rather take the word of an actual real live artist myself. For example Soltek recommends 3500k bulbs which are ridiculously yellow-orange. They've convinced galleries and museums of the superiority of their bulbs. You can't even see the color of the paintings, it's so distorted. The Ott 5000k bulbs appear very green to me. Caveat emptor!

When all is said and done, you might prefer the 5000k.

[Chris Saper]

HI all,

I recently ordered a pair of 6500 bulbs from www.1000bulbs.com, and I just love them. They are the spiral shape and are very strong, 42 watts (equivalent to 150w), 2800 lumens, and best, they screw into a regular light socket ( with a little extender) . They are really cool, literally and figuratively.

The mfg is TCP, consumer info 800-771-9335.

[Tony Pro]

Originally Posted by Chris Saper

HI all,

I recently ordered a pair of 6500 bulbs from www.1000bulbs.com, and I just love them. They are the spiral shape and are very strong, 42 watts (equivalent to 150w), 2800 lumens, and best, they screw into a regular light socket ( with a little extender) . They are really cool, literally and figuratively.

The mfg is TCP, consumer info 800-771-9335.

AWESOME!!! I have been looking for something like this!!!

I just placed an order!

Thanks Chris!!!
Tony

[Garth Herrick]

Hi All,

Holly Snyder introduced me to the Diffraction Grid method of visually comparing the CRI (color rendering index) of light sources, and I got a grid sheet of my own to compare my findings with hers.

I use JUST Normlicht Color Control Daylight 5000 fluorescent tubes in my studio. They are 36 watts, 5000K, and 48 inch T-8 tubes, and are rated at 98 CRI. This is as good as a fluorescent light can get.

I don't have a north light window to match, so 5000K is comfortably cool for my purposes. Marvin's argument for 6500K illumination seems valid for the purpose of matching a north light, which would be cooler due to the dominant illumination coming out of the blue sky.

For comparitive purposes, I've grouped four diffraction grid spectrums into one chart. From the left, the first two strips are from my camera, and the last two are from Holly's camera. I believe we both have the same camera (Nikon D100), and the same brand diffraction grid sheets. I shoud note that the spectrum looks very different to a camera than it does to the naked eye. Cameras have their limitations.

The 5000K Just Normlicht, and the 6500K Lumichrome appear to be about equal and genuinely 98CRI each. The 5000K Lumichrome, is not as good as the JUST Normlicht, as it shows more gapping in the spectrum. A Standard cool Philips tube is clearly way down on the CRI scale as there are wide black gaps.

So if you need to match north light, the 6500K Lumichrome tubes That Marvin uses look best. If you prefer 5000K, then JUST Normlicht is your best option.

Garth

[Richard Monro]

Marvin,

When I was setting up my new studio I researched lighting extensively. Hopefully the following will help. Color Rendering Index is very important as is the Kelvin temperature. Both must be considered together to get the best light compromise...and it is a compromise. North light is about 7500 Kelvin according to some sources and tends to be more blue and balanced in spectrum than south daylight. However, the reflected color from your studio walls and ceiling will influence the color you see. Hence my statement about chosing the best compromise.

Lumichrome flourescent bulbs at 6500 kevin and 98 CRI seem to be the best compromise of both criteria for bulbs on the market for the studio artist. Going with lights that are between 5000 and 7500 kevin and with a CRI greater than 92 should work well in any case.

If you want to get very technical you can do prismatic spectral analysis to verify that your new lighting reasonably matches your north light. In the end though it will come down to what pleases you as your art will ultimately be displayed in lighting that will be anything but north light.

Wish you success.

[Richard Monro]

Garth must have posted his reply as I was writing mine. Way to go Garth. Your diffraction grids show that there is a reasonable spread of light Kevins that can be chosen.

[Michele Rushworth]

Chris, thanks for posting that link for the screw-in 6500K bulbs. I have two light stands in my studio that I like to move around depending on what I'm doing and it would be great to have decent bulbs to put in them. I'll check out the TCP bulbs.

[Richard Monro]

Chris, I checked your link and could not find the 6500K bulb. What was the CRI for this bulb?