[pure-silver] Re: Ruminations On Subject Brightness Range In The Real World
- From: "BOB KISS" <bobkiss@xxxxxxxxxxxxx>
- To: <pure-silver@xxxxxxxxxxxxx>
- Date: Wed, 12 Sep 2012 08:54:22 -0400
Don't forget the following sources:
1) On Google Books you can find the journals of the SPSE (Society of
Photographic Scientists and Engineers). From my region, I cannot find a
free download. This has happened to me before with Google Books but most of
the rest of you might be able to download PDFs.
2) SMPTE (Society of Motion Picture and Television Engineers) also did TONS
of research in film, devs, optics, etc which easily apply to still
photography. If you join, you have access to PDFs from their journal from
1916 to present day.
When I was at RIT, I was a student member of both and found them
amazing info resources.
CHEERS!
BOB
-----Original Message-----
From: pure-silver-bounce@xxxxxxxxxxxxx
[mailto:pure-silver-bounce@xxxxxxxxxxxxx] On Behalf Of Laurence Cuffe
Sent: Wednesday, September 12, 2012 5:51 AM
To: pure-silver@xxxxxxxxxxxxx
Subject: [pure-silver] Re: Ruminations On Subject Brightness Range In The
Real World
Sent from an iPad,
On 12 Sep 2012, at 02:35, Jean-David Beyer <jeandavid8@xxxxxxxxxxx> wrote:
> Laurence Cuffe wrote:
>>
>>
>> Sent from an iPad,
>>
>> On 11 Sep 2012, at 23:19, Dana Myers <dana.myers@xxxxxxxxx
>> <mailto:dana.myers@xxxxxxxxx>> wrote:
>>
>>> On 9/11/2012 3:07 PM, Laurence Cuffe wrote:
>>>> As just a grey scale the number is surprisingly small, circa 450
>>>> different levels. For further reading on this i would recommend
>>>> looking up the DICOM grey scale standard,
>>>> http://medical.nema.org/Dicom/2011/11_14pu.pdf
>>>> And the research reported therein.
>>>> this scale does seem limited by the concept of simultaneously able to
>>>> distinguish, that is, if we take the full range of light conditions
>>>> from extreme tropical sunlight to a fully dark adapted eye, then the
>>>> eye can operate over a larger range of light levels than those
>>>> defined by the scale, however the scale does seem to give a fair
>>>> representation of the ability of the eye to distinguish light levels
>>>> in one image.
>>>>
>>>>
>>> [...]
>>>> For colour work, it would seem logical to assume that the maximum
>>>> number of distinguishable colours would be around (450)^3
>>>
>>> Is that really true? I'm not sure I see the logical jump from
>>> N-shades of grey to M-colors.
>>> But I don't know otherwise, admittedly.
>>>
>> The assumption here is that our ability to distinguish the red component
>> of an image is unlikely to be enhanced by the amount of green or blue
>> light also present. from this assumption we deduce that if we can
>> distinguish between 450 different levels of each of the primary colours,
>> then we can distinguish at most 450x450x450 colours in total.
>>
>> However colour vision is a curious thing, as Dr Land's red blue
>> experiments have shown
>> http://neuronresearch.net/vision/files/retinex.htm so I would not have
>> absolute faith in my conclusions. it is not my field of expertise.
>> also I'm fascinated by Jean's mention of an increased ability to
>> distinguish colour in a moving image. This makes sense, as we mostly
>> sense difference rather than absolute value. I was unaware of that work
>> prior to this discusion.
>>
>> All the best
>> Laurence Cuffe
>>
>>> Cheers,
>>> Dana
>>>
>>>
> If you stuff this:
>
> Bell Ttelephone Laboratories J.O. Limb C.B.Rubinstein
>
Thanks for that, Jean-David.
There is some fascinating literature out there, and I hope my maths is up to
it.
All the best
Laurence Cuffe
> into Google, you will find a lot of the work we did at Bell Labs in the
> early 1970s. I am even guilty of contributing to some of these efforts.
>
> --
> .~. Jean-David Beyer Registered Linux User 85642.
> /V\ PGP-Key:3EDBB65E 9A2FC99A Registered Machine 241939.
> /( )\ Shrewsbury, New Jersey http://counter.li.org
> ^^-^^ 21:30:01 up 18 days, 10:33, 3 users, load average: 4.66, 4.59, 4.42
>
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