i'm somewhat puzzled! ?

[ABERS]

I visited Tate Britain last Tuesday and took a few shots in and around the galleries. Whilst sorting through the 40 or so images deleting the dross, I came across this one, a vain attempt at something 'arty''

It's the juxtaposition of two so called 'art' installations. One a concave mirror, which I presume allows the viewer to make up his/her own distorted view of the world and the other a sign with the copy somewhat strangely edited.

I was just about to consign the image to the bin, when I noticed something a little puzzling.

The sign is reflected in the mirror, but the letters are the correct way round

No fiddling or pp'ing I can assure you. How does this happen?

[Paul Montgomery]

Blimey - that's got me stumped - have to confess I haven't the foggiest. If its a concave mirror shouldn't the reflection be upside down too  (look at yourself in a spoon...)
As an 'art installation', is it possible there was another, inverted version of the text somewhere else in the room that you hadn't noticed before?

[Hinfrance]

Could it be a double reflection? It doesn't look like the far piece of text would be visible in the mirror from the angle at which you are taking the shot. But I could be hopelessly wrong, I often am.

[ABERS]

I've retrieved from the yet unemptied recyled bin.



This time it has a couple of people included, but it still seems to have happened, and the are up the right way as well. I'll have to go back or pay a visit to the Science Museum!

No other signs in the gallery. It was taken at a very acute angle so as not to get my ugly mug in shot. Perhaps there is an angle where the non-upside down mirror writing effect comes into play?

Have I accidently turned the laws of physics on its head?

[Beaux Reflets]

My my, looking at the two shots I'm inclined to guess that the writing is being projected onto or through the mirror taking advantage of the large empty areas of wall to allow the combining of two images (Is the concaved glass a one way mirror?) - Certainly a great effect to make one think!

[Hinfrance]

OK, I have staying with me smart *rse science type chap who reckons that the only viable explanation is that the concave mirror is not a mirror at all - it's a screen onto which a real time image is projected.

Either that or it's magic. Which is the more likely explanation

[Oldboy]

Either that or it's magic. Which is the more likely explanation

Magic. 

[Beaux Reflets]

A screen and a mirror in one; or Alan is working a good joke on us all 

[ABERS]

I can assure you this is a concave solid mirror, totally opaque with no projection devices trained on to it.

All I have done is taken a photograph, no funny business and no mucking about. If I could post the raw image I would.

Here's another shot taken from head on, last year on a visit to give you an idea of scale and positioning.

[Beaux Reflets]

Is the mirror glass thick enough to "project the view seen through its polished edge"  similar to distorted projections in beveled mirrors but more apparent with a parabolic rear surface ?  Hence the elongations in display - Off to bed to think about this in more depth but the mirror must be a lens within in its self 

[Hinfrance]

Where's Hugh Evans when you need him?

[ABERS]

Googling about I found this

http://answers.yahoo.com/question/index?qid=20070506192212AAg1dBS

And this
Concave or converging mirrors curve inward like a spoon (the side that holds soup). This gives these mirrors the ability to create an image when their curvature bounces light to a specific area in front of them. This area is called the focal point. From far away, objects will seem upside down, but as you get closer and pass the focal point, the image flips and magnifies.

Answer found since I was as close as possible to the edge of the mirror.

Does it explain why the writing also appears the correct way?

It's as I suspected all along it' something to do with soup!

[Graham]

Googling about I found this

http://answers.yahoo.com/question/index?qid=20070506192212AAg1dBS

And this
Concave or converging mirrors curve inward like a spoon (the side that holds soup). This gives these mirrors the ability to create an image when their curvature bounces light to a specific area in front of them. This area is called the focal point. From far away, objects will seem upside down, but as you get closer and pass the focal point, the image flips and magnifies.

Answer found since I was as close as possible to the edge of the mirror.

Does it explain why the writing also appears the correct way?

It's as I suspected all along it' something to do with soup!

  I was about to post something along those lines (Honest!) All my optical theory books are in the loft at the moment ...but I'm sure it'll be because it is effectivly a "Negative" power reflector.
  The laws of reflection are very closeley related to the laws of refraction. If you take a negative power lens of sufficient strength, About -4.00 diopters and view an object with the lens a sufficient distance from your eye, about arms length, the image will invert, this is because the lens /eye distance is greater than the focal length of the lens, this causes the light rays to cross over at the point of focus and invert the image.
  Alan, I'm sure you remember setting fire to things by focusing the sun's rays with a magnifying glass! You can do this because a positive power lens (a magnifyer) causes the light rays from the subject (the sun) to converge to a point focus on the opposite side of the lens. With a negative power lens the point of focus is on the same side as the subject.

  Anyway, what I rekon is happening with your mirror is that the inverted "Mirror Image" is being fliped back to "Normal" by the negative power characteristics of the concave surface.

  I was trying not to responde to this thread as I knew it would make my brain hurt!
                      Graham.

[irv_b]

Graham you took the words right out of my mouth!

[ABERS]

Graham

I forgot you were into optics, both kinds, and your explanation confirms what Irv was about to say!

So it's nothing to do with soup then?