In the meantime, the original image for this "lesson" was taken with my iPhone using the SlowShutter camera app set for an 8-second exposure. The sky was pretty gray and the whole scene rather monotone so I put my sunglasses in front of the iPhone lens to add some color. The first image below is the original with no post-processing.
This image was brought into the Iris app on my iPad, cropped and then filters added as outlined below.
The cropped image (to remove blown out sun in the top of the image) with the Grunge Frame 2 of Dust 'n' Scratches applied is shown above.
The image immediately above shows the result of application of the Retro filter to the image above it.
It wasn't really sunset, but the magic of iPhone photography plus the hint Harry and Teri Lou gave me about using sunglasses in front of the lens makes this final image, signed using the Impression app, appear to be a gorgeous sunset. NOTE: The first and last images may be clicked to show full size images.