Toronto First Canadian Place Rejuvenation | 298.08m | 72s | Brookfield | MdeAS Architects

[egotrippin]

Therein lies the issue with "white" glass. Glass has a much higher reflective property than the previous marble, and in addition has iron oxide impurities that contribute a green hue. Even if this has been removed, I'm sure a very trace amount remains. Coupled with the reflections throughout the course of the day, the glass casts a somewhat minty hue. Other times it looks stark white, and other times it really picks up the reddish-orange from the morning and evening skies. Though, based on my observations in the flesh a lot of the cameras here aren't white balanced correctly, and are contributing more blue and green tones than actually exist.

 

[Bruvyman]

Therein lies the issue with "white" glass. Glass has a much higher reflective property than the previous marble, and in addition has iron oxide impurities that contribute a green hue. Even if this has been removed, I'm sure a very trace amount remains. Coupled with the reflections throughout the course of the day, the glass casts a somewhat minty hue. Other times it looks stark white, and other times it really picks up the reddish-orange from the morning and evening skies. Though, based on my observations in the flesh a lot of the cameras here aren't white balanced correctly, and are contributing more blue and green tones than actually exist.

From Wikipedia entry on glass:

Color in glass may be obtained by addition of electrically charged ions (or color centers) that are homogeneously distributed, and by precipitation of finely dispersed particles (such as in photochromic glasses).[42] Ordinary soda-lime glass appears colorless to the naked eye when it is thin, although iron(II) oxide (FeO) impurities of up to 0.1 wt%[43] produce a green tint which can be viewed in thick pieces or with the aid of scientific instruments. Further FeO and Cr2O3 additions may be used for the production of green bottles. Sulfur, together with carbon and iron salts, is used to form iron polysulfides and produce amber glass ranging from yellowish to almost black.[44] Manganese dioxide can be added in small amounts to remove the green tint given by iron(II) oxide.

Interesting. I guess this would mean, if applicable and as we already knew, that the glass is not pure white after all. I completely disagree though, that the higher reflective qualities of this cladding are contributing perceptibly to a green hue. There is rarely a green cast caused by either the ambient light or a camera's colour balance settings in daylight conditions.

 

[gei]

i don't deny it looks green in some of the pictures posted here.... but i'm staring at FCP right now at my window in bright daylight and it looks completely white. not a hint of green at all.

 

[dt_toronto_geek]

I am too. At first glance it's beautifully white today under a sunny bright sky however if you compare FCP to something truly white in the foreground or background and look back & forth you'll see it's not perfectly white. Under less than sunny skies (like yesterday) the slight green minty hue is more perceptible.

 

[Traynor]

First of all...The glass isn't white. The glass is transparent with a white acrylic layer behind. Each panel is five layers fused together and the second from bottom-most layer is the pure white component.

The reason the tower appears white in the sunlight is the direct reflection properties of a single bright light source (The Sun). The rays of the sun are direct and penetrate to the white sublayer and reflect directly to your eyes appearing "white". The scattering properties of the glass layer that produces the green tint are overpowered by the direct light rays of the sun.

However, on cloudy days or on the shadowed side, the light hitting the facade is less intense and evenly dispersed and also from ALL angles simultaneously. This means the light reaching your eye is equally from the scattering properties of green tinted glass and the white sub-layers, producing a slight minty hue.

 

[Traynor]

Furthermore:

For this particular cladding, even in direct sunlight there is an added "Shadow Effect". This is due to one of the layers under the outermost transparent glass being a patterned Fritted Ceramic layer. The stacked triangle shapes are three dimensional and cast a small shadow on the white base layer when the direct Sun's rays strike the surface obliquely. (Which is nearly all the time except sunrise and sunset.)

The nature of shadows produced from direct sunlight, on a pure white surface is a blue cast. Shadows are not grey on clear days. They are actually made up of all the light from the ambient blue sky minus the yellow spectrum of the direct sunlight. (Step outside and look at your shadow on pure white snow. The shadow is blueish not grey.)

These tiny blue shadows multiplied a billion-fold, tints the direct sunlight a slight blueish cast making the new FCP appear a slightly off white shade compared to a piece of opaque white plastic would in the same lighting.

 

[Traynor]

I was bored so I did some diagrams to demonstrate my point:

First a screen capture from the Redefining First Video Tutorial that shows the layers that make up a new panel.

(Found here: http://www.redefiningfirst.com/ )

Next, a diagram for how light is reflected and refracted in Strong Daylight. The power of the direct Sunlight bouncing off the white substrate layer overpowers all other refracted green-tinted light.

Finally a cloudy day or the shadow side of the building:
Light from the sky comes in all directions and is even in illumination. On clear days the blue sky removes the yellow spectrum of sunlight and pre-colours the entering light with a blueish cast. The random direction of the light allows for multiple rays to be scattered in the two glass layers on top of the white substrate which are tinted green by the glass impurities and outnumber the rays directly bouncing off the white substrate.

I hope this clears up how the panels can appear greenish in some lighting and more white in others. (Please forgive the simplified diagrams.)

 

[toto]

Traynor, is your real name Seldon Cooper?

Thanks for the explaination.

I've mentioned this before, but all reflective surfaces appear different based on the colour temperature of daylight, which can vary as much as 7500 degrees Kevlin during the day. Can't understand why some people don't get how this affects the colour of glass.

 

[Traynor]

^You're very welcome.

There are actually many more complex events happening to the light rays due to the slight separation of the two top-most layers of glass. The light paths are doubly refracted as they enter and leave the density of the glass to the air-space containing the Ceramic Frit, then back through another layer of glass, before exiting again to the outside air... (Remember your high school Physics class with light refraction? I do and I'm 48! LOL)

But I won't bore everyone with further diagrams.

 

[khris]

The only time it appears green to me is in shadow or cloudy days. Sunny days it is definitely white in appearance. I already knew why, but thank you Traynor for explaining it thoroughly for everyone.

 

[caltrane74]

Uploaded with ImageShack.us

From Queen Street.

 

[Xray_Crystal_Junkie]

all reflective surfaces appear different based on the colour temperature of daylight, which can vary as much as 7500 degrees Kevlin during the day.

Um I'm not even going to bother looking up this phenomenon you claim.. But the temperature of light at the earth's surface varrying by as much as 7500 degrees Kelvin [Kevlin (sic)] is absolutely ridiculous! You do know that a degree of Celcius is the same change in average heat as a degree in Kelvin right? (The Kelvin scale just starts at absolute zero while Celcius starts at the fusion/melting point of water). Maybe you get that kind of varience on the surface of the sun but not the glass of FCP! lol

 

[Ramako]

Um I'm not even going to bother looking up this phenomenon you claim.. But the temperature of light at the earth's surface varrying by as much as 7500 degrees Kelvin [Kevlin (sic)] is absolutely ridiculous! You do know that a degree of Celcius is the same change in average heat as a degree in Kelvin right? (The Kelvin scale just starts at absolute zero while Celcius starts at the fusion/melting point of water). Maybe you get that kind of varience on the surface of the sun but not the glass of FCP! lol

That is why you fail.

 

[Mongo]

Um I'm not even going to bother looking up this phenomenon you claim.. But the temperature of light at the earth's surface varrying by as much as 7500 degrees Kelvin [Kevlin (sic)] is absolutely ridiculous! You do know that a degree of Celcius is the same change in average heat as a degree in Kelvin right? (The Kelvin scale just starts at absolute zero while Celcius starts at the fusion/melting point of water). Maybe you get that kind of varience on the surface of the sun but not the glass of FCP! lol

No, that is actually quite correct. The colour temperature at sunrise/sunset is typically about 2000 to 3000 degrees Kelvin, clear daylight is around 5500 to 6500 degrees Kelvin, and a partly cloudy day (which, depending on the location and density of the clouds, can block most of the direct sunlight while allowing the heavily blue scattered light to dominate) can have a colour temperature reaching as high as 10000 degrees Kelvin. Total colour temperature range: 7000 to 8000 degrees Kelvin.

You really come across as being arrogant and ignorant in your dogmatic refusal to do even the most basic research (it took me all of 10 seconds to find out this information on the Web). You remind me of those so-called 'scholars' who in the 17th century refused to look through a telescope at the moons of Jupiter, because they just KNEW that they could not exist.

 

[Irishmonk]

You remind me of those so-called 'scholars' who in the 17th century refused to look through a telescope at the moons of Jupiter, because they just KNEW that they could not exist.

Or Keith David refusing to put on the sunglasses in "They Live".