When Day Turns to Night
On a project in Pittsburgh, the night view for a day|night backing of downtown had to be fully simulated from the day. With no night image to use as guidance, here is how we went about creating that night view.
In the past year or so a production hired us to produce two custom backings in Pennsylvania, one of downtown Pittsburgh and another at an out of town location 45 minutes away. Due to weather and scheduling issues, these had to be photographed on the same day, and, given the time of year, capturing the corresponding night views for both meant we would be working until about 11 at night. Unfortunately this was not feasible, so only one location could be photographed at night.
Given the architecture, the lighting dynamics at night of the out of town location would have been more difficult to predict and recreate in post, ultimately forcing downtown Pittsburgh to be the day only capture with night being created in post. At first glance this may seem imprudent, but no one lives in downtown Pittsburgh and the city dies after the end of the business day, so I would have had my work cut out for me regardless.
Arriving at 9:30 AM to one of the top floors of a Pittsburgh Skyscraper, I started composing the view. To maintain proper scale, this view was photographed much wider than usual since the backing could only be hung 8 feet from the set windows. Typically we are able to capture all that is needed in a single row panorama, however here we decided to capture two rows just to ensure we had enough information to work with given the proximity to set.
When capturing a panorama this wide the final image will have a significant amount of perspective distortion, which is the warping the occurs near the edges of a wide image. Many think this is caused by a defect in camera optics, however it is solely due to the angle of view and not something that can be corrected for while maintaining a rectilinear view. Backings need to be rectilinear within the center of view, but the edges not so much. To this effect, we created two different panoramas and stitched them in post to cancel out this uncanny distortion. Then, to enhance the facade of the building across from us, especially at night, additional windows were added in post.
Given we were facing towards the sun, a nicer sky that was not blown out was dropped into the image. Although this works well with building edges, thinner objects like railings and antennas retain halos and must be masked out. I did have an internal battle with me, myself and I on whether or not to nix the vents, which stick out like a sore thumb. However, empty commercial roofs never look right. With the day now finished, it’s on to the night.
With any day|night backing, our first step is create a simple night from day conversion using a proprietary process we developed. This always ends up being a bit too cold to work by itself. Typically layering the true night image on top counteracts this, especially since we tend to process that a bit too warm. Of course, with this image, we did not have the true night and instead added additional warming layers to achieve a natural feel. As with any city-scape, the street lights will always make the the bottom of the image brighter and warmer then the top and a subtle global gradient was added to this effect.
More discernible gradients were then added on a building by building basis starting with the Post Office & Courts. This building is only 10 stories and what we can see of it is close to the ground and street lights. Here I added an intense brightness and warmth to the base with a dramatic falloff towards the top. With the Koppers’ building though, the section we see is further above ground calling for a less intense gradient with a gradual falloff. Of course the pyramid on top of that building, which would be lit as well, would require similar treatment as with the Post Office & Courts. As surely as water will wet us, as surely as fire will burn, The Law of Diminishing Squares holds true.
To add nuance, visible street lamps were lit with appropriate light scallops and reflections added along with even more subtle gradients on building facades perpendicular to and/or far above the street. These facades would be lit more with indirect light off of street facing facades calling for a subdued touch. Now you will notice that the building in front of camera did not receive any additional gradients, which was intentional. Doing so would have flattened the image, whereas here we have created depth.
Next it came time to light up the the Koppers, BNY Mellon and the UPMC signs … both of them. Admittedly I missed the second one on my first pass too.
Now, at long last, it is time to talk about the window lights. With a downtown conversion like this, I lit up well over a 200 windows, which is certainly needed for this image. Insofar as which windows to choose, it is best to keep them random but to also pick windows that are already bright to begin with in the day version, or at least not pitch black. These will render nicer in the image and the backing. Of course this is easy to figure out, which brings me to the real nuance most miss.
In addition to the windows, the exterior sills and jams need to be lit up as well. These would not be as intense as the actual widows, only a slight increase in brightness and warmth is needed. Also, one has to be careful to not have any light spill onto the building facade, which faces away from the window and would not receive any in real life. All this does add to the tediousness, however without it the image will appear fake even if one is not able to articulate why.
Last, my attention turned to the top of the building on the left where I took a few artistic liberties on how it would look. First, there appeared to be several LED strip lights that would provide up lighting onto the roof, along with a few sconces. I painted light onto all of these as well as appropriate scallops on the building. Above the first floor of the penthouse exist a few ornate rafter trails, offering a great position for some down lighting. In reality there are no lights here, but I added them in anyway. The very top of the building is likely an elevator suite housing the mechanicals with the rod iron gate being more of a vent then a window. Regardless, I chose to light this up as well with some spill onto the jam. The final touch was a brush of light onto the large stone orb atop the building, and the sky was darkened as well.
After the better part of two days, the night view was complete and the file was off for client review and prepress.
