I am studying carmel's answer found in the thread How to export non-blurry eps images?
[I]n Preview in Mac OS X, you can make the thin white diagonal lines across each of the squares disappear by unchecking "Anti-alias text and screen art". Of course, the downside is that then any text (e.g. figure axes, etc) is not anti-aliased. Unfortunately, unchecking that has no effect on blurriness if you're using imagesc.
The OP is not active in the userbase so I have to open this thread. I would like to know more about those white diagonal lines across each of the squares. I would like to get a basic example what he means by his claim.
How can you reproduce the anti-alias method in Preview of Any OS X?