please explain this weird visual effect

[tr888]

Although I consider photography an art form, this question isn't about the art: I'm taking crude utilitarian pictures with an autofocus camera (Nikon Coolpix) and encountered something weird (at least to me).

We are trying to learn who made some silverware passed down in our family, and so I photographed the mark to send a picture to an expert. I haven't sent it yet because the picture is oddly inverted: the engraving shows up like embossing and the embossing shows up like engraving.

The photos
(Edit: two pics now in the album; spoon-bowl-up is correct to my eyes; spoon-bowl-down is the weird one).


The letters STERLING are actually engraved but they look embossed in the picture. The cursive upper-case D is actually embossed in a shallow oval scoop, but the oval scoop looks embossed and the D looks engraved.

How did that happen?

Thanks for any light you can shed on this matter. :blushing:

 

[pmsnel]

Maybe you need glasses because I just see the embossed and engraved in the right places... (Or might be due for a new pair myself! )

 

[tr888]

Is this an optical illusion affecting my eyes and my brain only?

On the one I have tagged as weird, does the oval itself look embossed or scooped/engraved to your eyes?
There are two pics now in the album. Spoon-bowl-up is correct to my eyes; it looks like the real-life actual spoon. Spoon-bowl-down is the weird one that looks inverted (engraved<->embossed, concave<->convex).

 

[OrionsByte]

Here's how I see each of them, and I'm understanding you correctly, I'm seeing it "right":

Spoon bowl down: Embossed oval, embossed "Sterling", engraved "D"
Spoon bowl up: Scooped oval, embossed "D", engraved "Sterling"

Not sure what you're seeing that would make it look different. There are several cues that point to a light source from top left of the frame, so that means that an embossed feature will be lit on the top left and shadowed on the bottom right, and engraved features will be the shadowed at the top left and lit on the bottom right.

Embossing/engraving can play tricks on the eyes under certain circumstances, but personally I don't see anything illusory here.

 

[Josh66]

I don't see it in any of those pictures (they all look 'right' to me), but I know the illusion you're talking about.

In this picture, do the letters look like they're raised, or recessed?
(They are recessed.)

 

[Ashlorraine]

I completely see what you are talking about! Thats strange....it is like an optical illusion. It looks like the "sterling" is popping up as opposed to being engraved..I can't even get it to look right in my head. Must be the lighting? Hmm no clue

 

[flyingember]

there's too even a shadow so we don't have a frame of reference.

for example, if there were obvious shadows going one direction we can determine which direction the text goes (in vs out) based on the shadows on the letter.

 

[Hartley]

Hi,

I think the illusion has to do with the light source - we expect the light to come from above, so the two with the spoon "bowl up" shade the impression the "correct" way, while the other two reverse it. The difference is subtle, but it sure looks that way to me..

Hartley

 

[Dwig]

Hi,

I think the illusion has to do with the light source - we expect the light to come from above, so the two with the spoon "bowl up" shade the impression the "correct" way, while the other two reverse it. The difference is subtle, but it sure looks that way to me..

Hartley

Bingo, the man with the correct answer.

Without some clear dominant clue about the position of the light source you brain defaults to assuming that light is coming from above as is does most often. When rotate the image so that the light is coming from the top of the print the hallmark looks correct, recessed. When the image is rotated so that the light is coming from below your brain, lacking any real clues, assumes it comes from above and perceives the hallmark as being raised as that is the only way the shadows and highlights would be where they are if the light was coming from above.

 

[tr888]

I've now been able to cause my brain to interpret the rotated image correctly. :crazy: Sometimes. Cannot do it "at will" yet.

It is easier to control what my brain sees with the images as thumbnails. But if I click on them to bring out to a larger size, it's much more difficult.

I should add that turning my monitor upside down doesn't remove the illusion.

 

[tr888]

I don't see it in any of those pictures (they all look 'right' to me), but I know the illusion you're talking about.

In this picture, do the letters look like they're raised, or recessed?
(They are recessed.)

They look raised to me.

 

[tr888]

Here's how I see each of them, and I'm understanding you correctly, I'm seeing it "right":

Spoon bowl down: Embossed oval, embossed "Sterling", engraved "D"
Spoon bowl up: Scooped oval, embossed "D", engraved "Sterling"

Yes, you're seeing it as I do: the embossed oval and embossed STERLING are tricks of the eye. There is no such spoon.