Step 1: Add a vignette
Open your image in Photoshop and duplicate your layer then we need to make a vignette. There are several ways you can create a vignette in Photoshop but one of the easiest is to go to Filter>Lens Correction. When the new window opens un-tick the correction boxes and click on the custom tab. Go to vignette and pull the Amount slider to the left so the corners of the image darken. Then click OK.
Step 2:Brighten some of the colours
The beauty with Lomo images is that rarely two shots feature the same bright colours in the same places and it’s easy to replicate this look in Photoshop. Click on the Channels tab next to the Layers tab and you’ll see RGB, RED, GREEN and BLUE. Which colour you change will alter the overall look of the image so it’s worth experimenting but for this image we’ll adjust the RED and GREEN channels.
So, select your channel, in our case red, and go to Image>Adjustment>Brightness/Contrast. It’s contrast we are mainly interested in and the further you pull the contrast slider to the right the stronger the colour changes will be. To see what the adjustment has done to the overall image you’ll have to click OK and select the RGB channel. If you don’t like the result simply open your history window and go back a step and start again. You can then move onto the other channels and adjust accordingly.
You can stop here but adding a little noise to the image will complete the shot.
Step 3: Add noise
Create a new layer and go to Edit>Fill and fill it with black. Next, go to Filter>Noise>Add Noise adding as much or as little noise as you wish. Click OK then go to the Layer Blending Mode and see which mode works the best for your images. Screen works particularly well or if you want something less striking try Overlay. Then reduce the Layer Opacity slightly to bring more of the image back through the noise layer.