Sometimes you might want to take a recent photo and make it look like it was taken with a vintage camera. Here's one easy way to do this. Note that the image processing software that I am using here is Gimp 2.6.1. Gimp is free software and can be downloaded from http://www.gimp.org/
Alright, just to give you guys a feel of what we're trying to accomplish, here are before and after shots of a photo that I took when visiting the Chinese Gardens in Singapore.
Step 1: Open the image of your choice in Gimp.
Step 2: Duplicate the image layer one time. You can duplicate a layer by clicking on the duplicate button at the bottom of the layers panel window or pressing Shift + Ctrl + D (in Windows).
Step 3: With the new layer selected, go to Colors->Desaturate. Pick 'Luminosity' among the options presented and then click OK. Your image should now look Black and White.
Step 4: Change the blend mode of the Black and White Layer to 'Overlay'. The blend mode can be changed from the drop-down menu at the top of the Layers panel.
Step 5: Change the foreground color to the following shade of Yellow: fbf2a3
Step 6: Go to Layer->New Layer (or press Shift + Ctrl + N). Among the Layer Fill type options, select 'Foreground color'. Leave everything else as is and click OK.
Step 7: Change the blend mode of the new layer to 'Multiply' and set its Opacity to 60. Your image should now have a yellowish tinge.
Step 8: Change the foreground color to the following shade of Magenta: e865b3. Once again, add a new layer with Layer Fill type as 'Foreground color'. Change the blend mode of the new layer to 'Screen' and set its Opacity to 20.
Step 9: Change the foreground color to the following shade of Blue: 0949e9. Again, add a new layer with Layer Fill type as 'Foreground color'. Change the blend mode of the new layer to 'Screen' and set its Opacity to 17.
Step 10: That's it! We're done. You may tweak the opacities of the Yellow, Magenta and Blue layers to make your particular image seem more authentic.