Go to Layer → New Adjustment Layer → Curves and switch from RGB to Reds. Then drag the line downwards a little for the shadows and upwards for the highlights, creating a slight “S” curve. Do the same for the Greens. For the Blues, drag the highlights down a little and the shadows up (for an inverted S shape). The shadows should now be slightly blue-ish, the highlights slightly yellow-ish.
Adjustment Layer: Curves
Create a new layer with
Shift + Control/Command + N, and fill it with
#000066 (RGB 0, 0, 102). Set the blending mode to “Exclusion.” Now copy the background layer by clicking it and pressing
Control/Command + J. Set the blending mode for this copy to “Soft Light.”
To decrease the effect overall, activate the top-most layer and then click on the background copy while holding the Shift key, thereby selecting both layers. Alternatively, you can add them to a group with
Control/Command + G. Reduce the layer’s (or group’s) opacity. Note that in Photoshop versions prior to CS5, you’ll have to reduce the opacity for each layer individually.
Achieve a simple retro look in a few steps.