Smart Object - When something is pasted from another form of software. It lets you go back to the original file and adapt it, and it updates in Photoshop. (essentially when many photos are used, they are combined into one, but can be adapted afterwards)
The combination of images, in order to see the sculpture without any people:
In order to change the skyline, I placed another image over the top, then used the quick selection tool to remove the people again.
Contact Sheets:
Used when in contact with a photography, and selecting a photo.
Lossless - file formats that are for print. - TIFF
Lossi - file formats suitable for the internet. - JPEG
PDF - Portable Document Format - A file format so you can send files between different users.
Drag the two TIFF files into acrobat reader - "combine files into PDF"
Save it as a PDF, then open on preview in order to print. Preview - layout - long edge binding & short edge binding - which side should be flipped, as if the images were bound.
Portrait - Long edge
Landscape - Short edge