[argyllcms] Re: How to create .sp files with an i1 Pro?
- From: Ben Goren <ben@xxxxxxxxxxxxxxxx>
- To: argyllcms@xxxxxxxxxxxxx
- Date: Thu, 13 Sep 2007 21:31:40 -0700
On 2007 Sep 12, at 2:09 AM, Graeme Gill wrote:
> There is a rather large disparity between the Graphic Arts
> standard Illuminant D50, and the sort of lighting most people
> use indoors. Even the higher quality 5000K Fluorescent lights
> don't have a spectrum that much resembles D50, and the Ultra
> Violet content of the lights is another wild card when combined
> with Fluorescent Whitener Additive in paper stock, since the UV
> output is often not closely controlled.
You ain't kiddin'! A year or two ago, I ordered a handfull of
compact fluorescent bulbs advertised as being 5000K with a CRI of
92. I plugged them into the living room, rather excited...and
immediately thought...``Gee, they sure seem somehow hollow and
excessively blue.''
So, I immediately broke out the i1...and, sure enough, they were a
perfect match for one of the standard F illuminants whose spectrum
is so bad that the G-M share tool couldn't even calculate a
temperature for it -- let alone a CRI. Fortunately, the company I
bought them from only gave me a minor hassle to return them.
The only difference with most of the rest of the lights in my
apartment is that they're reddish - yellowish - orangish instead
of bluish...and they cost a fraction of what the ``CRI 92'' bulbs
did. The kitchen, I've mentioned, has tubes that (according to
G-M) really *do* have a CRI of about 92 (I forget exactly
what). It's good enough for a ``rough guess'' sort of look at a
print, but for real evaluation I step outside.
> The closest practical lighting are filtered Quartz Halogen
> lamps, such as Solux <http://www.solux.net/>, although I'm not
> sure that the UV content is the same as real D50 daylight (in
> fact they seem to boast that it has low UV output, making them
> rather unsuitable for viewing substrates with FWA under standard
> D50 conditions.)
I've spent a lot of time over the years looking for affordable
quality lighting. The Solux lights are tempting...but awfully
expensive.
I'm currently toying with getting some Lumiram Ecolume CF bulbs
for ``normal'' lights (they claim 5000K and a CRI of 96), plus a
pair of their 6500K CRI 98 tubes for the kitchen. They're cheap
enough that I won't get too upset so long as the CRI is over 90. I
figure they'll be much, much better than what I have now, even if
they're not in the same league as a skylight. (The landlady might
complain if I started cutting holes in the roof, as would my
wallet....)
If the tubes are as good as they claim, I'll probably even make a
viewing booth from them, and maybe also a softbox. But that's
probably just wishful thinking.
Cheers,
b&
P.S. I took samples of the light in the gallery at the Tempe
Library where my pictures will be shown in a couple months. I've
got the .txt files to make .sp files, and G-M says they're a close
match to a standard ``A'' illuminant. Good thing I took the
samples.... b&
Other related posts:
