I tried to take a photo of a steam engine in Bucharest but unable to find one I asked for help and got one from Kevin, thank you! Now I can proceed to writing a GIMP tutorial about turning a regular photo intro "steampunk photography" like photos taken in the XIX century.
Those familiar with my graphic tutorials probably know that I use to address the beginners, showing some techniques as simple as possible (and only pre-built filters), followed by some pointers about advanced usage and also letting it open, with a lot of optional steps and alternative ways, so I will try to do the same this time.
So what's more appropriate for a steampunk photo than a steam engine? Nothing... so I got a steam engine photo (thanks again Kevin!) and opened it into GIMP and applied all the basic operations (crop to take out the unneeded parts and focus to the subject, adjusted the colors, resized to decrease the file size and sharpened to compensate for the resize) and got it decent looking:
Then I applied the Old Photo filter (Filters > Decor > Old Photo), where I decreased the border size a bit (for my image size the default value was a bit too large). After reading the next steps, decide if you want to let Defocus on (I let it on, as it is the default):
And instantly we have an old looking photo:
We can leave it as it, looking old (150 year old?). But what I want is a steampunk image, like we are living in an alternate reality without electronics, and the photo was just taken yesterday with steampunk technology. So I made it more vivid by adjusting the color curves:
And the defocus option in applying the filter was a nice touch in making the photo look old, but I want to experiment with taking it into the opposite direction and apply a heavy sharpen:
For a result I find interesting:
Now going over the top, add a few coffee stains (Filters > Decor > Coffee Stain) to the photo (accident happens with old photos). The stains are drawn randomly, so try a few times until you get something you like:
And the final result, which we obtained only with pre-built effects:
Beyond the basics
Sure, applying the sepia effect automatically was easy, but with manual control we can get something much better (I think), so let's redo that step manually, like pros.
Back to the initial (color) photo. Turn it into black and white (a quick way is to desaturate it - Colors > Desaturate, but you can also use convert to grayscale and then back to RGB).
The result is as expected, black and white:
Now select a light brown as foreground (painting) color, add a new layer, fill it with that light brown. Optionally rename the layer "sepia" to help you identify it.
Add a Layer Mask to the brown layer and leave it white (full opacity):
Now go to the background (photo) layer, select everything, go back to the sepia layer, select its mask and paste (paste into the mask, not into the image layer). Anchor the selection.
The result will look funny, but do not get scared:
Just change the layer mode from "Normal" to "Color":
And you will have a good looking sepia image (now we can merge the layers):
If we want a border we can add it using the Fuzzy Border filter (Filters > Decor > Fuzzy Border), just take care to select a good color for it (use the color picker and take a sample from the picture) and a good size:
And the result is something like this:
If you want to defocus add a little Gaussian Blur or if you want to go the opposite way just sharpen it:
And also you can play with the Color Curves: