Lighting for black

[Prasad Kumar]

I was reading a book "Film Production Technique", and it said "Cinematographers will “light for black”...they will light a dark area to just outside of the latitude of the film so that they get a richer black."

I didn't quite understand what "lighting for black" means to get the richer black.

Let's say the film stock latitude is 3 stops. If I light the black objects but make them fall outside the latitude of the film, it's still not going to give me any details. Then

1) Why do I have to light them?

2) How will I get a richer black when I light them?

Thanks.

Edited February 6, 2021 by Prasad Kumar

[Satsuki Murashige]

This is pretty old advice, and is not relevant these days (if it ever was). You’re right that it doesn’t make any logical sense. Pure black on negative film is just clear film, which is the result of zero exposure. Adding light into those pitch black areas will either add a slight amount of shadow detail (thus no longer black), or do nothing.

What really matters is how you print the film - if you print it lighter you will get grey, weak blacks. If you print it darker, you will get a richer black (up to the limit of that print stock). 

What will help you achieve a denser black in a print is to slightly overexpose the camera negative, since you will have to print it down to get back to a normal image.

I think maybe the advice came from the idea that seeing just a hint of shadow detail made the shadows seem perceptually richer than seeing no detail? Film stocks kept improving over the decades, getting sharper, less grainy, and capturing more dynamic range. And print stocks kept getting deeper blacks too. There used to be a print stock called Kodak Vision Premier 2393 that had richer blacks than the current Vision 2383. It was more expensive than the regular 2383 and they eventually discontinued it. 

It’s possible that some color print processes (aside from the Technicolor dye-transfer process) didn’t have great blacks back then when this advice was common, so maybe pure black didn’t always look that great when projected? Just a guess.

[David Mullen ASC]

I had this discussion recently... I think the confusion comes from cinematographers mixing up a couple of concepts, i.e. (1) what is a good pure "black" in a print, and (2) what perceptually looks "black" in an image, and (3) how to get keep clean shadow detail at very low levels in a print. 

So the advice you read from the past is combining all of these concepts, which is confusing because they are different issues. Black is the absence of detail but many cinematographers use the terms "blacks" and "shadow detail" as if they were the same thing.  Even today, you hear younger cinematographers talk about "how do I get rid of noisy blacks" in digital.  Pure black in digital is easy, crush the dark areas to 0 IRE. It might not look good but the blacks will be black. What they are really asking is how do they get an attractive, naturalistic level of low shadow detail that is clean, not noisy.

(1) As Satsuki says, black on a negative is clear and black in a print is D-max, the most dense area of the print. That's purely technical, un-artistic definition of "black". If you want to get a perfect black, you don't need exposure on the negative, you could process an unexposed roll of negative and make a print of it... you don't even need a negative, simply shine light directly onto the print stock and turn it black!

If you took an unexposed roll of negative and processed it normally, it would be clear other than some base fog density. Now if you took that negative and printed it at increasing levels of light, printed it in the teens, the 20s, the 30s, the 40s, and hit 50 on the printer light scale, you'd notice that the prints were getting denser and deeper blacks until you hit D-Max on the print stock.  So the most simplistic answer is that to get good blacks in a print, besides having something black in the frame, is to expose the negative so that it prints in the high 30s and 40s, i.e. overexpose the negative.

(2) There is the issue of perceptual black, that black looks blacker relative to light, so if you have a bright highlight in the frame, the surrounding blacks will look blacker to the eye. This is helpful to know if you actually can't get a pure black for whatever reason, so a small bright highlight will help make the surrounding blacks look less milky.

(3) If you want some shadow detail in that blackness, you have to add some light there.  So the "richest" image with dark shadows with detail involves both exposing the negative well for a good black and then adding the minimal amount of light into the shadows that detail starts to appear.
 

[Tyler Purcell]

Also, maybe "light for black" could mean a trick that I was always told, which is to insure none of your shot is below the threshold of actual black unless you're intentionally doing so. 

I try to light with enough spill so things don't completely fall off the chart. This is super important with film, where you may only have 5 stops of latitude below middle gray. With digital, it's less important because there is so much more latitude in the blacks. It's actually hard to get pure black in a lit scene, unless you purposely try. 

[Satsuki Murashige]

David, do you think that color release prints from the Eastmancolor era had comparatively weaker blacks than the black and white release prints from the same era that most of those cinematographers were used to?

If so, maybe that was part of where the advice came from? I’ve never read quotes from any cinematographers saying this about shooting B&W or Technicolor process, it seemed to be always in relation to single-pack color negative. Color reversal film also never seemed to have this issue, though I suppose that is more still photography-related.

The theory makes sense to me, given the amount of sliver in B&W that color normally doesn’t have. But of course, it’s impossible to say from my perspective because all of the color prints from that era that I’ve seen were already faded drastically. Of course, many B&W prints in good condition still appear to have good black levels.

[Tyler Purcell]

5 minutes ago, Satsuki Murashige said:

But of course, it’s impossible to say from my perspective because all of the color prints from that era that I’ve seen were already faded drastically. 

That's always been my issue too, remembering what things were like, when all we see is faded prints these days. 

[David Mullen ASC]

11 hours ago, Tyler Purcell said:

Also, maybe "light for black" could mean a trick that I was always told, which is to insure none of your shot is below the threshold of actual black unless you're intentionally doing so. 

I try to light with enough spill so things don't completely fall off the chart. This is super important with film, where you may only have 5 stops of latitude below middle gray. With digital, it's less important because there is so much more latitude in the blacks. It's actually hard to get pure black in a lit scene, unless you purposely try. 

I think the confusion comes from the phrase itself "light for black" -- black is the absence of information so any light that creates density on the negative is by definition, information, i.e. less than black.  If "exciting the silver with photons" actually got you better blacks than no exposure at all, then when you shot a black square next to a dark grey square, in the print, the dark grey square would be blacker than the black square, which would be dark grey... which makes no sense.

[David Mullen ASC]

9 hours ago, Satsuki Murashige said:

David, do you think that color release prints from the Eastmancolor era had comparatively weaker blacks than the black and white release prints from the same era that most of those cinematographers were used to?

If so, maybe that was part of where the advice came from? I’ve never read quotes from any cinematographers saying this about shooting B&W or Technicolor process, it seemed to be always in relation to single-pack color negative. Color reversal film also never seemed to have this issue, though I suppose that is more still photography-related.

The theory makes sense to me, given the amount of sliver in B&W that color normally doesn’t have. But of course, it’s impossible to say from my perspective because all of the color prints from that era that I’ve seen were already faded drastically. Of course, many B&W prints in good condition still appear to have good black levels.

I know that the same advice was given for b&w photographers, to give some exposure to the shadows, but it became more common in the era of color negative and print films. With dye transfer printing, black was not a problem -- in fact, they routinely flashed the b&w matrices to reduce contrast (though that's flashing a positive so reducing contrast by darkening the whites, not lifting the blacks.)

I think the advice to add some fill into the darkest areas for color negative was partly due to the slow speed of the stocks and the poor quality of duping films for mass release prints -- ideally you'd print from a dense negative but when the speeds were 25 or 50 ASA, cinematographers routinely underexposed them -- for example, during the age of 50 ASA film, you commonly hear "I lit sets to 150 foot-candles" when technically you'd need 200 foot-candles for an f/2.8. And this was with normal processing.  So if the negative is a bit thin, then you'd want to keep some detail in the dark shadows with lighting because a pure blank black area would make the base fog and grain level more obvious.

[Satsuki Murashige]

That’s great info, thanks David. I think you’re right that dupe printing was also a huge factor.

With B&W photography, there was the common advice to ‘expose for the shadows, print for the highlights’ - essentially exposing to the right since you could pull so much detail out of the highlights. But I hadn’t heard of any cinematographers actually filling the shadows with lights because they were worried about getting rich blacks. I feel like exposure choices were usually much more bold in B&W films than in color films in the 1940s-1960s, it doesn’t seem like anyone was worried about silhouettes or having just slivers of the negative exposed for dark scenes back then.