Are you sure the images are aligned Christina? Something looks a little odd to me and I wonder why. I would expect a little more sparkle going on the 1st image you posted. The mountain skyline is odd in places. I notice that it's in aRGB though but don't think that is the reason. I applied a very weak s curve to increase contrast, tone mapped a little - have to from a jpg and then a touch of unsharp mask mostly bringing up the ripples in the water.
It's bought up the lamp posts a treat too! No signs of miss alignment so not sure why you have lost contrast. I usually don't touch aRGB images. No point in using it when posting on the web.
I would expect to have to do some additional work on a merge like this. Maybe the simple method shown in the video would be better. The video also shows an easy method of generating layer masks but remember you can always modify their tone levels. The link I posted indicates the sort of change that you need to make to each of the images. The video is more detailed. Using the GIMP for this sort of thing I simply duplicate layers but in PS the adjustments shouldn't be permanent. Pass on that aspect as I don't use it.
On Chauncey's post not sure what the layer mode in PS is but if you do as he suggests and then place the original image on top and adjust it's opacity it's possible to weaken the colour effect as much as desired. Easiest way to find out which layer mode to use is to just try them. In GIMP if I remember correctly it's overlay mode.
John
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