Why match the background color when shooting to the one that is going to be used in the final presentation when the subjects will be cut out anyways?

Question

In this (Corporate Portraiture Advice) question the photographer explains that he/she is going to use a white background when photographing coorporate portraits even when the final presentation would have the subjects against black, the idea was to cut them out from the background in post.

In some of the answers and comments people objected rather strongly to this use of white background when final presentation would be on black, arguing rather for a black background.

Why is that? Why should a black background be preffered?

My initial thinking when reading the question was that if enough light spilled on the background it would be compleatly blown out thus making the cutting out trivial.

Answer 1

What exactly is your question? The reason to match the color of the backdrop with what should be the background color in the final image (on a website in this case) is obviously that you "get it right in camera" or at least very close to it. It saves you the whole process of cutting out the subject from the background. Maybe you missed the intention of the suggestion, but the point of using the black background is that it will not be cut out anyways.

Answer 2

Because otherwise you'll get a whitish halo around the cutouts, particularly for dark-haired people to be pasted on black background. People's features, including but not ending with the hair lining their head, do not sort themselves into fully opaque and fully transparent pixels. While you'll usually cut out even for display on black background, if the original photograph has been cut from a black original, it will blend better.

Also you write:

My initial thinking when reading the question was that if enough light spilled on the background it would be compleatly blown out thus making the cutting out trivial.

Absolutely not. You won't be able to separate a white background by blowout behind a light blond person with "enough light spilled on the background". Any blowout background will blow out because it gets its own strong lighting: additional flashes, additional lamps. Enough light for a blowout will strengthen the halo effect.

The advantage of a blowout is that you can make it really bright while there is no way to get blacker than black, and near-black color is common. Saturated blue can be a useful cutout compromise for dark background use. Its halo artifacts at least blend better with black.

By the way: black? Are you sure you should not be having a word with the web designer? Because black is hard.

Answer 3

I have two main reasons.

The first one is the removing of the background. Yes, you can spend some time removing a background, either using a green screen or using the white background, but take a try and see that cutting away hair is one of the most time-consuming maskings you can do, if you want to have it right.

But you also can lose detail, and probably you want to reduce the file dimensions to hide some of the already mentioned "Halo".

---

But my second reason is that the lighting of a portrait on white and one on a dark one is potentially different.

Using a white background you need to avoid rim lighting, probably hair light. On a dark background, you probably want to use those styles of lighting, or a more dramatic one. I don't know.

The composition is potentially different depending on the background. The background is vital on the style.

I do not remember the name or the exact quotes, but a well-known artist (an impressionist) was asked by an assistant if they could hire some rookie painter that wanted to work in the studio, and the assistant argued that "he could start painting backgrounds". The artists responded, "But I still do not know how to paint a good background".

The background is a vital part of the portrait.