Another Sunday morning at the Cathedral: Story behind the photo

I have been asked to explain the process behind my "Another Sunday morning at the Cathedral", so here goes.  Hopefully this will introduce you to a couple of techniques in Photoshop that you may not know about, but otherwise there is not a lot to creating an image like this, except waiting for the right conditions and a bit of time in processing.

Below is the finished image.  It shows a view looking out over part of Napier city, with St Johns Cathedral dominant on the left of shot, the famous Norfolk pines that extend along the edge of the beach running across the centre and the cliffs of Cape Kidnappers in the right in the distance. 

"Another Sunday morning at the Cathedral"

"Another Sunday morning at the Cathedral"

This image is made up from 2 separate photos, shot on the same morning, from exactly the same spot.  At first glance it might be hard to see the need for 2 images but the key to it is that the shot that I used for the bulk of the image was shot about 10 minutes before sunrise, and at that time there are no street lights on (and if there were then they wouldn't have had much effect as it was quite light). So I have added them in from an earlier shot.

LOCATION:

These shots were taken from a spot in a local public park, which is accessible by climbing over a low fence and walking up a little used trail that leads to a house next to the park,  The hardest part of getting to the location and shooting is trying not to wake the dogs in the yard of the house, which is literally a few feet from where I am sitting.  Sadly I didn't achieve that goal this time, the dogs heard me, decided to let everybody know that they had heard me, and so I had a head pop over the fence from the homeowner to say hello.  It didn't bother me too much (I was doing nothing wrong) but probably had them wondering what I was doing perched on the side of the hill with a camera in the dark.

SHOTS:

These are the 2 photos that I used for the final image, in a before / after type slider so you can see the differences between them.

I set up my camera on a tripod and composed a shot covering the view of the city below.  I took a few test shots, tweaked the composition then I took the 1 frame that I used in the final image that is on the left of the slider above. It was taken about 1/2 hour before sunrise and was exposed / proceseds in Lightroom to capture the street / building lights properly as this is the part of this image that I wanted to use. The overall image has a blue cast to it, and is a bit blown out in the sky, but that didn't matter as the parts of the image I wanted to use were the nice orange parts (and some of the green areas as well, more about those later!) in the foreground.

I then just kept taking shots, tweaking the exposure settings and checking the back of the camera (and not moving the camera at all), until the sun rose over the sea about 1/2 hour later, trying to get the best / brightest colour in the sky and city.  I picked the best image (on the right of the slider above) and used that as the base for the finished image.

The image on the right of the slider makes up the bulk of what you see in the finished image so was exposed / processed to have good brightness and colour in the sky and the buildings.  It is a nice image by itself, but lacks a bit of interest in the buildings in the foreground, hence the need for a blend

PROCESSING

Both of the images above were taken from Lightroom into Photoshop, and each put on a separate layer. Below is a screenshot from the Photoshop "Layers" panel.

BLEND MODE

The layer "blend mode" of the top layer (in this case the darker photo) was set to "Lighten".  When you create layers in Photoshop the default blend mode is set to "Normal"; this means that all the pixels on the upper layer in the stack will overwrite the pixels in the lower layer.  So all you will see in a "Normal" blend mode stack is the top layer.

There are many different blend modes other than the "Normal" one (I don't have the time or the knowledge to explain them all), but the "Lighten" blend mode will compare the pixels in the top layer (the one that has the blend mode set to "Lighten") to the pixels of the layer below (in this case the lighter image) and will show whichever of the pixels is brightest.

So effectively the "Lighten" blend mode will combine the brighter bits of the upper layer with the brighter bits of the lower layer, and show the combined bright areas, as you can see in the split image below.  The left side of the slider shows the brighter image, the right side blends it with the brighter bits of the darker image.

As you can see above while the blend mode has brought the streetlights through onto the brighter image, there are some areas of the blended image which do not look right (the sky has the brighter blue parts of the dark image replacing the darker parts of the brighter orange sky), so I needed to do a bit of manual blending to get it looking right.  But it is a good starting point.

MASKING

Another feature of Photoshop that makes it very powerful is masking.  Any layer can have a mask added to it, and that mask will effect which parts of the layer are visible, and to what degree.  The mask that I added to the top layer is visible to the right of the layer thumbnail in the image below.

As you can see the mask has black on the top half, and white on the bottom.  When a mask is created it is normally all white.  White areas in a mask allows the corresponding area on the layer to be visible, and Black hides the corresponding area of the layer from view.

Once a mask is created you can paint within the mask to add black (completely hidden) or various shades of grey (partially hidden) to hide parts of the image.

So in the screenshot above, the mask attached to the top layer means that the top (black) areas are not visible and the bottom (white) area is visible.  Again this is only effecting the top layer which has the mask attached to it.

The left side of the split image below shows the blended image without the mask, the right side shows the image with the mask.  In the right image the top parts of the blue/darker sky are not visible because the corresponding areas in the mask on that layer are black and therefore hide that area of the darker layer from view.

FINAL TWEAKS

So with the images blended in Photoshop all that I needed to do was take it back into Lightroom and add the finishing touches.  One of the hardest parts was to get rid of the green tinge that some of the streetlight had (this is caused by them being fluorescent lights, which show up as green to a camera).  To do this I carefully applied an adjustment brush to the green areas with the white balance of that brush set to a warm / magenta setting (which turned them back to a more neutral colour).  Then I darkened a few areas in the foreground, and some of the lights, and lightened a few areas (like the Cathedral) that needed to be more prominent, to create the final image.  The split image below shows the shot out of Photoshop on the left and the final image on the right (there is a slight perspective change in the final image, probably cause by me cropping a little bit more before saving the image)

So that is how I created "Another Sunday morning at the Cathedral"; please leave any questions/comments in the comments below.