I am having a **** of a time trying to use BitBlt.

I understadn all the concepts of masking etc. but I am repeatedly having a problem where I put a new 'tile' over the old picture, the colours of the picture layers combine, where all I want is one to write over the other.

I have a front picture box (white bg), a buffer picbox (black bg)
The tiles I have tried drawing with black bg and white, and with a mask with black and white in alternating areas.

First I paint the mask onto the back picbox, using vbSrcPaint
Then I paint the sprite tile onto the back picbox with vbSrcAnd
And finally, I vbSrcCopy the whole thing to the front picBox.

No matter what combo I try, I can't seem to get this right...