Thank you!

The "ord" function was, as you stated, the key to making this work. My immediate need is resolved.

Clearly there's a subtlety to substr of which I am unaware. $binimage[$thisrow] is just a sequence of storage locations containing bits representing pixels. I, the human being, don't care what they represent; I simply want to know whether the bit I'm looking at contains 1 or 0 and the only way I know how to address that is to grab the byte containing the bit and then try to look inside that.

You appear to be saying that substr will return the ASCII value represented by the number contained in the selected byte(s) rather than just a sequence of 8 bits I, the computer program, can manipulate how I choose.

In reply to Re^2: I've muddled my bit and byte formats. by murrayn
in thread I've muddled my bit and byte formats. by murrayn

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