How to take photo of bottle green T shirt

[Thad E Ginathom]

I think...

Grey card is more for exposure: white card is for colour temperature.

But grey, if a properly neutral grey, will work for both. But with white, our eyes can more easily see that it is, or is not, white.

Put it in the middle of t-shirt. adjust using viewfinder, not lcd screen colour temp until it *looks* white. Or use your camera's auto-custom-setting, if it has it; Sony mirrorless cameras do. Mine will adjust for uneven-spectrum colour cast as well as temperature. 

[Tarun Kumar Ghosh]

Hi Kumar.

I'm mystified by the problem.  I hope one of our fellow Members knows of a good solution. 

Anyway, two things to try come to mind.
1.  I wonder if polarization of the light may affect anything.  Do you have a polarizer, or can you borrow one?
2.  I wonder if ultraviolet might have some play in the result.  A UV filter might make some difference.

Do you have an image to share of this "bottle green" shirt that is coming out blue?

I took one image but how can I insert it in my reply. In the insert image option I was prompted for a link.