Hello Bob! But this means, that i1's white tile calibration also was made with "cold" device, so such calibration was not perfect for "warm" conditions, so readings made after i1 "warming" were stable but not really accurate.
............................................................
Being simple-stupid, I found years ago that manual readings from my old
i1Pro increased steadily up to about 10 readings, then they levelled off. So
I always did 10 readings on a patch before taking any serious measurements.
I just assumed that the electronics took a while to warm up.
Best regards, Alexey Gribunin, UNIT Color Technologies, Moscow, Russia.
Alexey Gribunin wrote:
But this means, that i1's white tile calibration also was made with "cold" device, so such calibration was not perfect for "warm" conditions, so readings made after i1 "warming" were stable but not really accurate.
It should be accurate if the instrument has a consistent "warmth" for each reading. Graeme Gill.
Could there be also some inherent balance in that lamp where the thinner filament burns with a higher output and the tungsten condensation on the lamp envelop dampens that output again? Till heat brings the tungsten back to the filament. You mentioned that the lamp is glued into its socket, is the window where the light is coming from quite small? The glue keeping the lamp isolated to bring it on temperature fast or the other way around creating a heat sink? Met vriendelijke groet, Ernst Dinkla Grafische Techniek Quad, piëzografie, giclée www.pigment-print.com On Sun, Feb 21, 2016 at 10:52 PM, Graeme Gill <graeme2@argyllcms.com> wrote:
Alexey Gribunin wrote:
But this means, that i1's white tile calibration also was made with "cold" device, so such calibration was not perfect for "warm" conditions, so readings made after i1 "warming" were stable but not really accurate.
It should be accurate if the instrument has a consistent "warmth" for each reading.
Graeme Gill.
_______________________________________________ Do not post admin requests to the list. They will be ignored. Colorsync-users mailing list (Colorsync-users@lists.apple.com) Help/Unsubscribe/Update your Subscription:
https://lists.apple.com/mailman/options/colorsync-users/ernst.dinkla%40gmail...
This email sent to ernst.dinkla@gmail.com
Ernst Dinkla wrote:
Could there be also some inherent balance in that lamp where the thinner filament burns with a higher output and the tungsten condensation on the lamp envelop dampens that output again?
Sorry, I don't know the details of QH lamp physics in enough detail to really know. I do wonder though, that if a portion of the filament is getting hot enough to be a measurable contributor to the visible output, that it would also be very close to burning out.
Till heat brings the tungsten back to the filament.
The reason that QH lamps burn out eventually, is that the tungsten is not evenly re-distributed when it condenses back. So eventually the filament develops thin spots. I would guess this depends on the filament geometry to a large degree. Typically this is a coil or coiled coil, so I guess this doesn't help.
You mentioned that the lamp is glued into its socket, is the window where the light is coming from quite small? The glue keeping the lamp isolated to bring it on temperature fast or the other way around creating a heat sink?
Hard to say. The lamp itself is much like any small "grain of wheat" lamp, a rounded end cylinder. The dome of the lamp is exposed, while the body is glued into the support. See <http://www.argyllcms.com/i1pro_lamp.jpg>. The Spectrolino is quite similar, although about 2/3 the size. Graeme Gill.
participants (3)
-
Alexey Gribunin
-
Ernst Dinkla
-
Graeme Gill