Super Bookmarks - Improved

In my previous:  https://www.instructables.com/id/Super-Bookmarks/ , I showed how to make bookmarks out of any envelopes.  This I-ble shows how to use windowed envelopes to make Super-Bookmarks-Improved.  The picture above shows the Super Bookmark-Improved in place with text visible thru the window.

In my previous: https://www.instructables.com/id/Super-Bookmarks/ , I showed how to make bookmarks from the envelopes that arrive at every house every day.  Lately, I've been receiving envelopes that look like the picture above.

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To make a Super Bookmark that uses the transparency of lower window in the envelope, see the picture below.
1. Slit the fold at top of the envelope.
2. Cut off on the solid line.
3. CAUTION: Cut the top ONLY!!! along the dotted line.
4. Cut the lower left corner at 45 degrees to provide space for book page corners.

You can use this now but I have a couple more refinements:

The picture above shows the bookmark in its usual position - the 45 degree cut is up and to the left.  When turning a page, the reader wants to put the page under the top surface of the bookmark so the top 4 inches or so are exposed under the window.  To make this easier, we want a couple of folds to guide the turned page into place without catching.

So at the top, fold the free edge up slightly.  Use the ink line as a guide.  Don't crease this fold.  Surprisingly, even after the book lies closed, this flap will spring up when you open the book.

Then fold 1/4 inch of the lower right corner of the window back and crease it with your thumbnail.  

None of these bookmarks has ever fallen out.