Digital BW, The Print

Harvey 

I don't think either of us know how these cameras handle grayscale mode,
which is what this has been about, so to reduce confusion, until further
info is supplied, I will bow out.

Todd

> Todd Flashner wrote:
> 
>> on 2/7/02 1:57 AM, SKID Photography wrote:
>> 
>>>>>> What I took from my question to Austin (Horses Mouth, about a week ago)
>> is
>>>>>> that these one shot cameras interpolate color, not detail.
>>>>>> 
>>>>> I do not understand how one can separate 'color' information and 'detail'?
>> 
>>>>> They are one and the same.  It's not like there are separate or different
>>>>> parts that make up the image.
>>>> 
>>>> Say your sensor is a grid of two sensors across by two down. In grayscale
>>>> mode you get a 4 pixel capture. You have 4 pixels of detail, represented by
>> 
>>>> one channel which has 4 pixels.
>>>> 
>>>> If the camera then applies an algorithm to give each of those pixels an RGB
>> 
>>>> component, that requires interpolation, and you'll end up 3 channels at 4
>>>> pixels each.
>>> 
>>> Stop right there and you have your answer.  INTERPOLATED INFORMATION!
>>> Not reality.  End of more real information.
>> 
>> Well, it depends on how literal we want to be. See, I think I'm correct in
>> an absolute sense, just not a practical sense. I not clear on how these
>> cameras work in grayscale, so I would forget anything I've said as it
>> relates to one shot cameras, but we could discuss this on a pure digital
>> science level (not that we should need to or want to), where I am
>> "technically" correct (to the best of my knowledge ;-)).
>> 
>> Let me just expound a bit, then we can continue, or drop it.
>> 
>> Above you asked how we can separate "color" from "detail" as they are one
>> and the same. Well we can and they're not. Austin used the right terms,
>> chrominance and luminance - they are different. Convert an RGB image to Lab
>> mode and you will have separated the two. The Luminance will live in the L
>> channel, and the chrominance in the a & b channels. look at each channel
>> individually. The L channel is a grayscale image which has virtually all the
>> detail, the a & B channels hold the color, and they are mush. So the context
>> in which I discussed "detail" is as it relates to luminance.
>> 
>> Then you say interpolation is the end of real information. That's true by
>> definition, but has no relevance to luminance, and "information" is a vague
>> term which I never used as it has not been defined. My point is that these
>> one shot cameras do record a luminance value at each sensor, thus detail,
>> and it is the chrominance which is interpolated.
>> 
>> The problem is that with the color filter on each sensor the luminance
>> (detail) values will be somewhat arbitrary at each pixel in a real world
>> imaging sense.
>> 
>> Todd
>> 
> 
> Todd,
> But the luminance is only captured for the specific color of the specific
> sensor.  Which is only 1/3 of the information needed to be real.  For example,
> the red sensor can only capture the 'luminance' of the red information, the
> rest
> of the luminance information, once again, is interpolated and therefore made
> up.
> 
> Harvey Ferdschneider
> partner, SKID Photography, NYC