Multiple Scan Assembly

How do you assemble multiple parts of an oversized scan?

Peter from CA USA, using Photoshop 7, Microtech scanner with Mac OSX, writes in with:

[Quote:] I am scanning a large number of images in two pieces. I am looking for a way to set "markers" on the overlapping sectinos of the images or some other method to make it easier to have a pixel-accurate re-assemmbly of the image. thanks, Pete

Fred Replies:

You shouldn't need markers or other devices. Just scan in sections making sure you have a good overlap... two inches is not too much.

Last year I posted a full tutorial, with pictures, in my article about : Bert Monroy

BASICS:

FIRST: make sure the file is large enough to accommodate the newly added "parts" to your scan. (Use: Image "Canvas Size" to enlarge the canvas)

NEXT: after scanning all the different parts, DRAG the first addition into the base file using the (V) MOVE tool. This generated a new layer over top of your initial scan.

SET LAYER BLENDING MODE: to "Difference" (Use the button pull-down on the layers palette)

NOW: the newly added scan will turn BLACK when it rests over top of the scan below. Move it around until the pixels coincide, and the overlap area turns perfectly BLACK solid, or as close as you can get it. Now they're aligned.

Continue to the next piece. SAVE OFTEN.