#apertus IRC Channel Logs

intracube: White point doesn't matter on a sensor as the filters are fixed.

It matters, of course, when mixing media or trying to deduce accurate colors after capture, but not in camera.

btw regarding white point... do you think it is enough to get 2 poitns and interpolate between them to cover others?

danieel: Explain?

the normal approach (sorry for pulling dng here) is to define 2 wp calibration points. one for 3200 one for 5600 k...

Oh no.

or one shall do every 100K calib matrix?

if the colour temperature was very low, lik 1800k, then the RGB sensels wouldn't fill up evenly

and some perceived resolution would be lost?

danieel: The only correct method is to use CIE XYZ positions and adjust the channels in the LMS domain using Sharp, Bradford, or CIECAT02 etc.

that is high math again :) not up for that at this time of day

we got almost no blue...

danieel: Not high math at all. Hell Bradford is a super simple matrix set. ;)

intracube: Nope. No such thing as white!

intracube: Hence my point, it is all arbitrary.

intracube: And the ability of the sensor to record levels is all hardware that ends up agnostic to the light

intracube: Matters in imaging in post for sure

but there will be a point at which the RGB filters in the sensor treat as 'white'

intracube: Nope

ok, I shut up now :)

Where it _can_ matter is in post imaging where you need a neutral axis to cut through the space perfectly

intracube: here is how it goes: sensor =1=1=1 what you mean by white is not really white, as there is a matrix coming on top of that, which leads to other RGB than equal

Exactly

No position in that entire space is magic

oh, i have an idea... we should program the channel bot, that if somebody writes that white or black is a color, he/she should be kicked from the channel :)

And only exist in the display referred domain

In manipulation of images, having R=G=B being achromatic is a much bigger deal

yes - i have an algo for saturation, which depends on R=G=B being achromatic, otherwise it would not work

intracube: Ask yourself, if you are sitting in a room, what is white?

And the moment that becomes irrelevant is the moment you realize how a sensor works.

troy_s: I meant white only as far as equal charge in each of the RGB channels

so treating everything as a wavelength distribution curve is the best?

danieel: Well it is just coordinates isn't it

Just like a CIE xyY map

We give it meaning

And again, if we are careful in imaging, we align our work for manipulation to our colorspaces

My point is really that our contexts determine what matters, and R=G=B=achromatic is truly something that is an issue in imaging and manipulation, not in the sensel world

that is not the biggest issue

(Ever)

Doesn't mattee

Ideally via a 3D LUT of course

troy_s: sorry, it's too late for me to follow

intracube: Think on it tomorrow

It has red, green, and blue filters, but how those filter is not a perfectly single band like a true RGB color space.

It is just an ignorant beast

an ideal rgb space - shall be treated like a 3 narrow spikes? or as three gauss distributed curves (think of 3 phase AC current)

Well almost but not quite as I understand it

But R / G / B shoot upwards and out in straight lines withing X / Y / Z, which is a bent nonorthogonal system

(Bent to isolate Y as luminance)

i found my answer... the narrowness just increases saturation

?

narrow is more pure color

Yes makes sense

And be less saturated of course

why?

night all

danieel: Because, as Fairchild says, color isn't physical

he was a person?

we call the company unfairchild these days... :)

Mark Fairchild. :)

And led Munsell labs for a while etc

I should move to US... so much is going on there

ICC

time to rest...

Back at you

off to bed now ... have a good one everyone!

sebastian created T244: image pipeline: highlight recovery. http://lab.apertus.org/T244

morning folks!

sebastian closed T71: invite all crowd funding backers to join axiom-community mailing list as "Wontfix". http://lab.apertus.org/T71

sebastian closed T219: Bluetooth as "Wontfix". http://lab.apertus.org/T219

good night