From: Paul Marquez
Subject: Joining pictures to make panoramas
Level: Intermediate / advanced
I would like to make panoramic pictures by joining several pictures together. Do I need special software to do this, or is it possible to do it manually?
Yes, there are many software packages available for making panoramas, but often I prefer to do the joining together of the images myself. I find it fun and very satisfying. The basic principle is to place the photos you wish to join together on two separate layers so they overlap, then carefully delete the upper layer to reveal other one underneath. I've taken a simple example - just two images joined together in one - see the boxout.
1) Two pictures to join together
Here are the two pictures we are about to join together. Note the similar areas at the neighbouring edges of the two photos.
2) Rotate A
Before we join any photos to make a panorama, we need to rotate them so the horizon is absolutely horizontal in both pictures. We will use Edit>Transform>Rotate
3) Rotate B
I've used a guide line to check the horizon is true. You can drag it down from the Ruler area at the top. The correct rotation in this case is minus 1.5 degrees. The other photo also needs rotating - by minus 3.4 degrees.
Now it gets interesting! After increasing the canvas size of the left hand picture, we will drag the right hand picture onto it using the Move tool. Now the two pictures are in one file, overlapping, placed on two separate layers. Areas at the edge don't quite match up, due to lens distortion. It's important to try and line up the areas to be deleted. Do this by nudging the upper layer side to side and up and down, switching the layer off and on to check the position. We can now start to erase the upper layer using the Delete tool set to airbrush.
5) Erase A
To disguise the join, I have erased along the inside of the cloud. Any further to the right, and I would reveal a slightly different shade of blue underneath, making the join visible.
6) Erase B
6) We can make the erased upper layer fully visible by switching off the background layer underneath. The lower left hand edge still needs to be erased. We will set the erase tool to a smaller size to avoid 'ghosting'.
7) Erase C We have deleted down over the plane fuselage and over the apron, revealing the lower layer which doesn't quite match up. Careful use of the delete tool will disguise the join. If there is any mismatch in lightness between left and right pictures, use the 'Levels' to tweak the upper picture until the colours along the join are the same.
When deleting is completed, select 'Merge layers' to combine the two pictures onto the background layer. Finally we will crop the photograph to cut away the uneven edges left after the rotation. There, finished! Who could have guessed that this photo consists of two pictures joined together?