Measuring the Color of White

Gary Eickmeier wrote:
lid wrote:

Gary, listen. On the Ott-Lite front page there is a link at the very
top to the "TrueColor(TM)" desk lamps. These are the ones that are a
daylight approximation. Now, did you buy one of these or not? It's
impossible to have a sensible discussion without knowing. If you
didn't buy a TrueColor lamp, there's no mystert about your odd
results.

It's really tough to find out from anything that is in my package or
anything on the cards that the new bulbs come on, what the color balance
is. So what is the Ott web site? I was operating on the Staples web
site. But I bought it at a store.

http://www.ottlite.com/ shows the products. Some of them are
"TrueColor", some aren't. See which is your product.

When I got home, however, and looked at my prints compared to my
monitor, they looked greenish. So I suspected the color balance of
the Ott light was not daylight, and I wondered how I might check
that. I don't own a color spectrometer of some sort, but I so own a
digital camera. So I am trying to think up a method of using the
camera to measure the white balance of the light.

Forget it. It can't be done. Fluourscent tubes do not have a
continuous spectrum.

Then why are you advising me on the True Color Ott lights?

Because, with care, it's possible to approximate a continuous
spectrum. That's what the "TrueColor" tubes do. But you can't
measure the colour temperature of something that is not known to be a
continuous spectrum.

I suspect you're simply bought the wrong product.

Andrew.

Gary Eickmeier wrote:
lid wrote:

Gary, listen. On the Ott-Lite front page there is a link at the very
top to the "TrueColor(TM)" desk lamps. These are the ones that are a
daylight approximation. Now, did you buy one of these or not? It's
impossible to have a sensible discussion without knowing. If you
didn't buy a TrueColor lamp, there's no mystert about your odd
results.

It's really tough to find out from anything that is in my package or
anything on the cards that the new bulbs come on, what the color balance
is. So what is the Ott web site? I was operating on the Staples web
site. But I bought it at a store.

http://www.ottlite.com/ shows the products. Some of them are
"TrueColor", some aren't. See which is your product.

When I got home, however, and looked at my prints compared to my
monitor, they looked greenish. So I suspected the color balance of
the Ott light was not daylight, and I wondered how I might check
that. I don't own a color spectrometer of some sort, but I so own a
digital camera. So I am trying to think up a method of using the
camera to measure the white balance of the light.

Forget it. It can't be done. Fluourscent tubes do not have a
continuous spectrum.

Then why are you advising me on the True Color Ott lights?

Because, with care, it's possible to approximate a continuous
spectrum. That's what the "TrueColor" tubes do. But you can't
measure the colour temperature of something that is not known to be a
continuous spectrum.

I suspect you're simply bought the wrong product.

Andrew.

lid wrote:

Gary Eickmeier wrote:

OK, I'll try this one more time, and that's it.

I'm learning about color management. To begin the process of color
management, you have to calibrate your monitor. From what I have
read so far, when you do this, the white that is displayed on the
monitor will be close to normal daylight, somewhere between 5500 and
6500K.

To compare the monitor images to your prints, you would have to view
the prints in light that is somewhere near daylight as
well. Ordinarily, we use incandescents indoors, around 3700K or
less.

More like 2800, usually.

above 100 watts, they are usually close to 3200. type b.
below that they drop fast. 2800 is probably a good guess.



Andrew.

lid wrote:

Gary Eickmeier wrote:

OK, I'll try this one more time, and that's it.

I'm learning about color management. To begin the process of color
management, you have to calibrate your monitor. From what I have
read so far, when you do this, the white that is displayed on the
monitor will be close to normal daylight, somewhere between 5500 and
6500K.

To compare the monitor images to your prints, you would have to view
the prints in light that is somewhere near daylight as
well. Ordinarily, we use incandescents indoors, around 3700K or
less.

More like 2800, usually.

above 100 watts, they are usually close to 3200. type b.
below that they drop fast. 2800 is probably a good guess.



Andrew.

lid wrote:

Because, with care, it's possible to approximate a continuous
spectrum. That's what the "TrueColor" tubes do. But you can't
measure the colour temperature of something that is not known to be a
continuous spectrum.

I suspect you're simply bought the wrong product.

Andrew.

Thank you Andrew - I can see now from the web site that there are two
lines of bulbs, True Color and Vision Saver. I can just replace the bulb
- if I can find one! Staples or Office Depot... need a bulb with "TC" on
it...

Gary Eickmeier

lid wrote:

Because, with care, it's possible to approximate a continuous
spectrum. That's what the "TrueColor" tubes do. But you can't
measure the colour temperature of something that is not known to be a
continuous spectrum.

I suspect you're simply bought the wrong product.

Andrew.

Thank you Andrew - I can see now from the web site that there are two
lines of bulbs, True Color and Vision Saver. I can just replace the bulb
- if I can find one! Staples or Office Depot... need a bulb with "TC" on
it...

Gary Eickmeier