Talk:White's illusion

Another illusion
I've found another impressive illusion within this one. Observe from about 1.5 metres. Focus without really concentrating on one of the white strips, at a point between two of the left hand ("lighter") grey bars.

Both of the vertical grey areas appear to be perpetually shrinking in on themselves - the effect is accentuated by moving your eyes slowly along the horizontal axis of the white strip you are looking at. MegdalePlace (talk) 22:00, 17 November 2007 (UTC)

Removed text
I removed a large section of text added by Ccharlie59. Because it was added all in one edit, and was unwikified, I thought it was very likely a copyvio, but I couldn't find a source to confirm it. However, the main reason I reverted it was because it completely overwrote the existing text. If someone feels this contribution wasn't a copyvio, feel free to merge it into the existing article. (WP:AGF and all that...) --Underpants 02:17, 24 May 2009 (UTC)

Definition discrepancies in the article
This article is contradictory. The 1st and 2nd paragraphs use apparent luminance to describe the illusion:

"Note, that although the gray rectangles are all of equal luminance, the ones seen in the context with the dark stripes appear brighter than the ones seen in the context with the bright stripes."

While the third paragraph, using the 1st and 2nd paragraphs as a basis, uses apparent color (perhaps 'shade' would be more correct), to explain the illusion:

"To see that the gray bars are the same color, you can stare at the image until your eyes begin to cross, then control your eyes until the gray bars line up, making one big gray bar, proving that the gray bars are the same color."

Luminance and color are distinctly separate attributes. It also appears to me that color (rather, shade), is more correct, or at least more applicable to the demonstrated illusion.

Lastly, when I apply the described method of proving that the colors (shade) are the same, I do not see the same color. It appears to be a stack of gray bars, alternating from lighter to darker (shade). However, I can tell that the grays are the same when I cover up each's entire surrounding colors (or use an image editor to verify).

By way of possible explanations, this is probably the result of perceived simultaneous contrast. It is also not uncommon to find within an individual that one eye's perception of color and/or luminance differs slightly from the other's. And further, it is also not uncommon for that effect to vary from situation to situation (i.e under different lighting conditions, as well as a slight change in the body's physical state such as after taking medicine or eating breakfast, the closing of one eye for a period of time such as with an irritated eye). However I need to say that for the above experiment's results, in testing a possible variation in my perception from one eye to the other (by covering up one, then the other, multiple times), I perceived no difference in color or luminance in observing the web page or my surroundings.

In closing, I propose a change in the article to align the terms in the explanation to be fully synonymous. I also propose that "shade" (or "color") be used instead of "brightness"; and if not, then that both terms be used simultaneously. And finally, the experiment in paragraph three did not yield the paragraph's "proven" results. I propose a change which at least includes: 1. the possibility that the experiment will not produce the intended result in everyone, and 2. why it might not produce the intended results.

I will attempt to edit the article myself within a week if no sound objection is found.

Hypocritus (talk) 13:41, 17 August 2009 (UTC)

Just a question
am I the only one missing fig 3 which is referred to in the Belongingness section? — Preceding unsigned comment added by 85.18.58.34 (talk) 17:10, 12 June 2013 (UTC)