DSLRUsers.com

Got a bit bored so went out and took a few shots.

Can anyone explain the green coming out of the red traffic light?


Did some distortion correction on this one and also cloned out about 2 dozen water drops that were on my filter.

Halation is the word.
jethro

Did you shoot in raw if so what did you "develop" the raw with, which program ?

Owen - I have a different interpretation of the green light within the red light. It appears to be burn through of the actual globe in the light - this can give a colour shift as seen here. The halation that Jethro mentions is the red glow around the green. This is red due to non interference from the globe itself and is a dispersion halo.

In my experience some raw coverters act strangely around some lighting particularly bright red lights, on each occasion part of the red light has turned green.

The red in the post box is reflected and the red in the light is transmitted. The transmission of this light is the problem due to the wavelength of the actual globe and the time span of taking the photo plus, of course, the actual dye makeup of the red lens. In this case Craig, it is not a WB problem.

Owen, can easily be rectified by cloning in some red.

Thanks for the interesting comments guys. I noticed it in another image and thought it very weird.

Would it be different between various lenses?

sirhc55 wrote:The red in the post box is reflected and the red in the light is transmitted. The transmission of this light is the problem due to the wavelength of the actual globe and the time span of taking the photo plus, of course, the actual dye makeup of the red lens. In this case Craig, it is not a WB problem.

Although the green on the red light is actually reflected light on the underside of the hood that sits atop the light in question, if I'm looking at the same thing that you are.

That surface would be black, and any reflected light from that surface would be net of any absorbed light, which would be dependant upon god-knows-what given that it's supposed to be a matt black, non-reflective surface.

That said, I'm not disagreeing with your assessment, except to say that the light from the red light itself seems, to me, to be totally blown and overexposed.

Regarding the wb, please look at the white printing on the postbox. On the main, front-facing surface, this appears to be very warm and yellowish in hue.

But now look at the rh side of the photo, at the OzPost logo on the short side of this postbox. Here this white painted component has a green tinge, as does the text below it.

As I tend to look in shadow detail for clues to wb "errors", I would be tending towards this area of the image for my clues to find the best wb settings, and thus I'm inclined to suggest that the wb is out, and would be looking to get this green tinge out of the image and seeing what that does to the rest of the image as my first port of call.

Adding to the confusion though is the point that this image appears to have been made under mixed lighting conditons: the area I'm looking at appears to be in shadow from a tree or plant of some sort, but in looking at the express post box adjacent to it, we can clearly see the shadow of the red post box projected upon it. Which indicates that the primary light source is coming from our right, suggesting that the shadowed area I'm looking at is not (or should not be) in shadow.

But in looking back at the red box, it is. There is mottled shadowing on the rh side.

And heavier shadowing on the lh side, indicating multiple lighting sources.

Finally, and also heloing me confirm my assessment, the yellow box also has a greenish tinge to it.

Nice image, btw.

gstark wrote:

sirhc55 wrote:The red in the post box is reflected and the red in the light is transmitted. The transmission of this light is the problem due to the wavelength of the actual globe and the time span of taking the photo plus, of course, the actual dye makeup of the red lens. In this case Craig, it is not a WB problem.

Although the green on the red light is actually reflected light on the underside of the hood that sits atop the light in question, if I'm looking at the same thing that you are.

I’m looking at the light itself which is round and is transmitting light. If it were a reflection, and considering the angle of the hood, the shape would be an ellipse.

Thanks for that Gary, I will check the WB in the image. I did notice the warm white text on the front of the post box and went back to the original to make sure it was not my processing, and the text was still warm - whereas the text on the side was still white.

I noticed the same in another image - around the red light was a ring of green. The thing ring completely encompassed the red light -in the same way that saturn's rings encompass it. This wouldn't seem to fit in with the hood theory as the hood is just on top. Any ideas on that one?

sirhc55 wrote:

gstark wrote:

sirhc55 wrote:The red in the post box is reflected and the red in the light is transmitted. The transmission of this light is the problem due to the wavelength of the actual globe and the time span of taking the photo plus, of course, the actual dye makeup of the red lens. In this case Craig, it is not a WB problem.

Although the green on the red light is actually reflected light on the underside of the hood that sits atop the light in question, if I'm looking at the same thing that you are.

I’m looking at the light itself which is round and is transmitting light. If it were a reflection, and considering the angle of the hood, the shape would be an ellipse.

In which case, I'm wondering if we're looking at the same item.

There are two red lights in this image. One is almost obscured by the yellow postbox. That is not the one I'm looking at.

The other one is the more prominent one, which has an almost round glow from the transmitted (red) light. This light has a partial hood, which is partially and very slightly obscuring this light on its lh upper side as we look at it, and there is (to me) a green reflection of something on the underside on this hood - to the immediate right of this transmitted light, which to me is the reflection of that transmitted light.

There is significant halation to the left of and below the light, essentially in the regions that are not covered by the hood, and to a lesser extent, continuing halation around the rest of the light.

Curiously - and seriously - if I tilt my head to the right, what appears to be the reflection from the underside of the hood looks a bit more like some form of lens flare.

Strange.