if you're talking about monochromatic sensors as opposed to bayer sensors you're rather specifically not interested in color perception.
Not true. See further about what the L channel of LAB is about.
you're the one that keeps bring up Lab.
monochromatic sensors produce monochromatic images. the only part that has
anything to do with color, in that equation, that is the frequency response range of the monochromatic sensor. which, btw, is not typically only green, nor is it identical to the human visual response. as that page i linked previously demonstrates, you need a special UV/IR filter unless you want to capture that data as well.
The 1st version of Photoshop came out in 1990. The current definition of CIELAB dates back from 1976. But you know so much about LAB that you did not imply that LAB is a by-product of Photoshop, right ?
yes, but your average person didn't have much exposure to things like color spaces before photoshop. similarly, not many people used online message boards before the advent of the internet, even though such things existed. and not a lot of people walked around with portable mp3 players before the ipod.
popularization , not invention.
in any case, the date you'd want for photoshop here is 1991, as version 1.0 was, and i know this is a shocker here, monochromatic. it did black pixels and white pixels, as it was written on and for the macintosh plus, which lacks a color monitor.
Intuitively we think of a color as having some amout of grey.
i don't. i think of gray as having some color components, specifically, whichever are the three primaries of the color system you're using.
A dark color would match a darker grey.
two fields of the same value have the same value, regardless of their hue, or lack of hue. it's tautological: either they have the same value, or they do not. yes, if you're
mixing paint and you mix a red pigment into a neutral gray you've made, you
will modify the value, because the pigment itself has some inherent value. (conversely, if you mix a neutral valued paint into that red, you will modify the intensity at the same time as the value).
And consequently we also think intuitively of a conversion of a color image to a Black & white one.
however, this is not what is happening in a digital camera. a digital camera has an array of
monochromatic sensors, with colored filters over them in usually the bayer pattern. the color image is interpolated from the monochromatic data.
LAB is a fruit of colour science which study how human beings perceive color (and that encompasses greys as well). The L channel in LAB matches this hunan perception of the amount of grey in a color.
correct. but this is not how humans see. in humans, the same visual cell that is responsible for scotopic vision is also
partly responsible for the blue and green parts of the opponent process, along with one of the cones. this is why blues and greens appear stronger at dusk. (and probably why bayer chose to duplicate the green).
there are three types of cone cells, one predominantly responsible for reds (L), one for greens (M), and one for blues (S). strictly speaking, even though Lab tries to duplicate the
neurological opponent process, RGB actually better duplicates the
biological way humans see color.
Tip: want to convert a color image to a B&W one which matches our perception of how a B&W image should look like? Just convert to LAB using a digital image manipulation software which supports LAB (Photoshop being one possibility), extract the L channel, and, voila, you have your conversion.
human beings do not see in black and white. there is no universal perception of how a b+w "should" look. in the film days, i typically used red and yellow filters. now with digital cameras, i will typically do my b+w conversions in
multiple parts, essentially using a red filter where i see fit, a green filter elsewhere, and a blue elsewhere.
for instance, see ansel adams "the camera" or "the negative" where he uses the term interchangeably with "brightness."
"the term" here being
luminance and not
lightness as in LAB color. since we've now lost context thanks to your repeated insistence that we're apparently talking about LAB color.
Ansel Adams used negatives and papers which under proper development would give a sensical image, one that matches reasonably well a perceptually correct conversion to B&W. The manufacturers of such negatives and papers saw to it. Ansel Adams does not have to worry about it just like you don't. Manufacturers of dSLRs and writers of RAW converters saw to it.
this is just so plainly ignorant i don't even know where to begin.
i'm not even a big ansel adams fan; i just happen to think he wrote a very elegant trilogy of books on the technical side of photography. but if you look at an ansel adams photograph and thing
the people who manufactured his film or paper saw to it that the image matched a perceptual correct b+w version of reality you are sorely mistaken, and should probably go take another art appreciation class. ansel adams neither tried to be "perceptually correct" nor did he rely on the way his film or paper was manufactured. rather, his prints are the result of countless hours of tweaking, waiting on top of mountains for just the right light, filtration, exposure/rating modification, development modification, dodging, burning, and all kinds of alteration you cannot even begin to imagine, in order to arrive at a photo ansel thought appropriately captured the way he wanted to portray a scene, or the emotional quality thereof. this why a modern print from an ansel adams negative is worth
significantly less than an ansel adams print.
in any case, most b+w film certainly does
not have the same color response curve as human vision, and b+w paper is
wholely insensitive to red.
