Re: Perceptual psychology OT

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FotoDave@aol.com
Date: 05/26/00-11:17:28 AM Z


> This is way off topic, but since I studied perceptual psychology under
> the guy who disproved the whole subliminal thing, I can't let this go by
> without comment. The brain cannot perceive visual information that the
> eye doesn't send it; the only way visual information gets to the brain
> is through the eye. If the eye can't detect it, the brain can't perceive
> it.

Hi Katherine,

Thanks for the clarification and explanation of many things. As you said, the
psychology part is off topic, so I won't ask or talk about those. The part
that is related to the discussion, however, is how many tones are needed in
digital photography and how it's related to contone one.

I didn't study psychology, so maybe when I said "the eye cannot see it," it
is not an accurate term; but what I meant is, is it possible that the eye
cannot detect the difference in some tones (especially due to the surrounding
image) but it still has an effect on perception and so it still needs to be
captured (I believe Jeff called it the "photographic nuances.")

Another example (that is often used in brochure of enlarger alignment tool to
show how important alignment is) is this: suppose you have an image of a line
made up by small dots that you can see, so the line is not crispy sharp. Now
you move away further from the image until you cannot see the dots anymore,
so the eye cannot see the dots and see it as a line. It looks fine. But if
now beside it you place a crispy line with the same width and tone, you
clearly perceive the difference between the two (one is sharper) although you
still cannot detect the dots!

I don't know how to explain this in psychology, but what I was trying to say
is that we *might* need to capture more tones than just the difference in
tones that our eye can readily detect. Just a "might" though. "Might not"
could be true as well although I believe more in the "might."

>> The practice was made illegal not because it worked, but because
>> legislators believe what they read in the newspapers.

Ah, thanks for clarification on this as well!

Sorry to all for talking about this thing, but hopefully those getting into
image capturing and digital printing "might" find some relavence.

And I will shut up now. :-)

Happy a great long weekend, all (I guess "all" in the US)!

Dave Soemarko


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