How to take photo of bottle green T shirt

[Thad]

Ah... Sodium vapour. I expect I knew at the time!

So those lamps emitted no red light, hence the absolute blackness of the PO box. Thanks a lot for the explanation :)

[Nishit Dave]

I used to enjoy an "illusion" caused by newly-installed street lights near my home in late 1960s. The lighting was very bright and sort-of orange. I think it was mecury-vapour lighting? I have forgotten. Anyway, there was a postbox. This postbox, like all other English postboxes, was red. I saw it regularly in daylight: it was red. Hoever, under this street lighting, it was absolutely, undeniably, black. It was impossible to see it any other way. Until the next day.

Those would be sodium vapour lamps. They emit light in a very narrow band. We used to do a study of diffraction using such a lamp in physics class.

The post box would reflect red wavelengths, which would be absent from the sodium vapour lamp's light. So you saw a black PO box.

[Thad]

I used to enjoy an "illusion" caused by newly-installed street lights near my home in late 1960s. The lighting was very bright and sort-of orange. I think it was mecury-vapour lighting? I have forgotten. Anyway, there was a postbox. This postbox, like all other English postboxes, was red. I saw it regularly in daylight: it was red. Hoever, under this street lighting, it was absolutely, undeniably, black. It was impossible to see it any other way. Until the next day.

[Hankosaurus]

... But with white, our eyes can more easily see that it is, or is not, white.

I am reminded of a story wherein a family decided to have a "candlelight dinner" at home.  They had a little girl of about five or six years old.  The little girl had only ever eaten yellow rice, not white rice.  Just before dinner was served, the electric lights were turned out; the table was dimly lit by candles.  The little girl would not eat her rice, saying she did not want white rice.  She wanted yellow rice.  The parents turned on the electric lights for a minute or so, to show her that the "white" rice was actually yellow.  Our minds "correct" for variations in light color, at least to some extent.  Consequentially, we don't always really know what white is really white.

As others have mentioned, light outside the spectrum of normal human vision (e.g. UV & IR) may be perceived differently by cameras' sensors or film emulsions.  Some white objects fluoresce when subjected to UV.  That may be a factor as well.

[Thad]

I started searching the Op's opening post, then realised the reverse order. Quite unusual.

Arw you seeing posts newest first? If so, I had the same problem and the answer is post #8 in this thread:

https://forum.jjmehta.com/index.php/topic,71368.0.html

[ISO]

I started searching the Op's opening post, then realised the reverse order. Quite unusual.

Anyway, nice discussion. I want to add that, based on my experience with flower photography, the camera and the human eye perceive things differently when it comes to bright colours.

The camera sensor is sensitive to UV and IR might give unexpected results for the bright colours. That said, green shirt looking blue is quite a radical shift that should not happen.

[Nishit Dave]

Always keep some Titanium Dioxide handy. Who knows when it may be needed?

[Thad E Ginathom]

Our eyes are very sensitive but our brains are very clever. "White" paper, cloth, etc etc is probably almost never actually white in the sense that we are talking about here. In fact, it may be adjusted to look whiter than white. Even washing powders may contain some invisible blue that enhances the "white" of our clothes. We will not see it consciously in most lighting, but check out the pictures of yourself dancing at the club, and see how bright your shirt shines, due to the higher UV in the lighting. Actually, I have some blue streaming lights outside my front door for special occasions, and they light up my cat's white fur too! Our brains adjust for it all.

But that Average Joe... Or just the guy who has no choice or control over the lights and must work with different temperatures just a few feet away from each other, or in different venues. I will take a camera reading from, say, a "white" vesti, it can be better than nothing. It can also be of very limited use as the light at that level can be very different to the light on the faces.

Photographing people, I got this hint somewhere: make the whites of the eyes and the teeth look right. I find that very useful. I also use the Indian Jasmine White Standard: the Jasmine in a lady's hair! lol

Outside of the studio, controlled lighting, or simple shaded daylight situations we must do the best we can. And be glad that we raw allows fairly easy correction!

PS... for a short time after changing white balance in the viewfinder, my brain's adjustment will pause and I can see it when I look direct. But it quickly "corrects" itself

[ashutosh1979]

Hi All,
Just for the benefit of anyone who is confused about white balance with a white card vs grey card vs white paper.

Here is an explanation

Yes as  Thad E Ginathom had said white card is used for white balance whereas grey card
(18% grey exact ) is used for exposure. Both need to be calibrated, so don't go for cheap ones.

Again, he is right to point that grey card can also be used for white balance. Because 1st statement is more valid for SLR or/ and in camera white balance. In case for digital images most image processing software will use white or grey tones( of any darkness) , to set the white balance. So don't need to rush for a "white card" if you have a grey card or similar.

As for using a white sheet of paper, it is hack not a recommended practice, senior photographers ( who can distinguish slight variation in hues ) would not EVER use it. However, for the average joe it would give good enough results which will correct very obvious colour cast. It is hack that will get you to the ballpark, not a "proper" solution.

I hope it clears any doubts regarding this issue. Please do correct above info if required.
Regards
Ashutosh

[ashutosh1979]

Used different camera but the result is the same. Also place it over white paper , no luck till now. I used my Nikon D 5100.

So the white paper / white balance thing did not help, but what was the result? was  the paper looking white but the t shirt was still blue ??
And what was the result with natural light ??

Now I'm very curious please do keep us posted with whatever your try.