I have a very sturdy, tall white noid iris, and looking at it with the sun shining through it, the center of the falls looks green to me. Is this something that all whites have, this tinge of green? I have never noticed it before and I know that most "green" irises are yellowish...

course not--white irises are indiviuals

I only have one white self which is Forever Blowing Bubbles and I can see a slight green tint on the underside of the falls in my photos. I can see a slight green tint on the falls of Society page. My other irises with white on the falls and coloured veins or edges look white to me.

There are other shades that tint falls and/or standards besides green. Some are very slight and some are quite obvious.