Re: How to stitch photo the hard way?

"david" <nospam@xxxxxxxxxx> wrote in news:h9ao4i$eu8$1@xxxxxxxx:

I have a photo larger than my scanner so I had to scan it as two
separate section with some overlapping.

The two sections are about 4000 x 3000 each.

Now I want to stitch them together. What I do is load each section
into a layer in photoshop and do a rough alignment. Now in order to
align them perfectly, I zoom in to pixel level at one side of the
overlapped area, make one layer 50% transparent and nudge until the
pixels line up.

Then I zoom in to the other side of the overlapped area. Often, I need
to rotate one of the layer to line up everything. Ideally I would put
the center of rotation on the previously lined up area, and then drag
the rotation handle to line up the current side. But at the pixel
level, the rotation handle is not visible. If I zoom out until I can
see the rotation handle, I can no longer see enough detail to line up
the two layers with pixel accuracy.

How do you get around this problem?

I know there are stitching function in newer photoshop and standalone
stitching software. But just for the challenge, how can I do this the
way I want?

Try using the "DIFFERENCE" screen mode (drop down in layers palete) I find
this invaluable when trying to line up pixel perfect joins

see Matching Oversized Scans