Around the time of her death about two years ago, Agnes Martin became less subtle, and started using colours and shapes that in her previous painterly practice would strike as unusual, even shocking. (if you have painted grey lines on beige paper for decades, black shapes get to be called shocking.)
Now Robert Ryman has started using colour…The interesting thing is that there are two separate shows of his work in the next year. One is at Dallas, and is a 40 year old retrospective. One is in Hamburg and is a selection of new works.
Rymans work in 1964, just before he started with white-on-white is not very good. The form has not been dictated, the colour is ugly and random, the size underwhelms, and it seems lazy/typical.
The 40 years since, are like a monk in the desert, counting grains of sand–the paintings there are almost endless in variation of texture, but in colour they purposefully lack. It is almost like he spent the last 4 decades figuring out how to sort thru texture, and now at the end, he is moving away, reclaiming and reinventing the flaws of his youth.
The paintings in Hamburg are tiny, small things, a little more then a foot square. They have the typical white field rawly placed on top of an under field -he has done this before, so it looks like water under a frozen lake…But this time, the ice has broken.
The sides of the paintings are alive with an almost northern romanticism, the colours he has chosen, a greygreen and a bright raw blue, remind of Caspar David Fredich’s landscapes or Joyce’s infamous “The snotgreen sea. The scrotumtightening sea”
Here is one of them: 
Seeing them in Repro of course means that their full power cannot be judged.
Here is one from 1964: