This is perhaps a stupid question, but the CYA test has always driven me crazy. Exactly how much does the "black dot disappear till the test has ended? Maybe it's an optical illusion on my part, but often that stupid black dot never really disappears, or it just distorts to an oval shape, or else I'm still imagining where the black dot is when it has in fact "disappeared." Am I the only one that this bothers? Maybe I'm doing the test too carefully, and staring down the tube too intently?
Any suggestions would be greatly appreciated. Thanks