There are a couple of factors, complicating the maintanence of this site:
Museums and galleries keep updating and changing their sites. Direct linking to images of paintings is for that reason not feasable. One has to use the search facilities
of their sites. I frequently check the links for not being dead, but the actual paintings being shown on-line may not be up-to-date.
There's a large number of untitled drawings and paintings, done over the period 1964-1980, that don't carry dates. Some works aren't even attributed with
the title "untitled" by De Kooning himself, carrying the title "no title" for lack of anything better.
The drawings can be variations upon similar
thematic material. It's not possible for me to memorize them all, so I have to look through a large number of catalogues and copies to check them.
Many fakes are available on-line. About always it's possible to be sure if a work is genuine by combining the following factors:
- Quality
- Style
- Artistic handwriting
- Signature and dedications
- Provenance
(- Forensic tests)
Some of De Kooning's paintings on newspaper are done that loose, that also for a trained eye it can get impossible to distinguish a lesser De Kooning
from a well-done fraud, just by looking at on-line images. There is no official entity authenticating his works.