After last week’s post on photographing white subjects on white background it’s only natural to talk about the exact opposite and photograph something black on a black background.
If you remember to photograph a white scene we basically set our exposure to about 2 stops brighter than the camera tells us and everything worked out, so you may expect that for a black scene you just set your exposure to about 2 stops darker and call it a day – but things are not that simple (if they were this would have been a very short post).
The first problem is that black on black will result in a image that is, well, black – we get a picture where it’s actually difficult to see the subject and when we scale the picture down it can become a completely black box with no visible details, in the white on white picture we had shadows that defined the shape of the white objects here the shadow doesn’t help us because it’s also black.
So if we want people to be able to see what we are photographing we really want to keep the subject almost black and make the background gray.
Than we get to the technical problems, when everything the camera sees is black there is very little light getting into the camera – this means this is going to be a long exposure and you need a tripod, it also means auto focus is going to be slow if you can auto focus at all and that you really want a camera with an optical viewfinder (your camera’s screen or an electronic viewfinder are going to be completely black).
Also, if you use a DSLR light coming in trough the view finder can completely mess up the camera’s light meter (because there’s much more light in the room then is reflected into the lens) so make sure to have your eye on the viewfinder or at least cover it with something.
Black surfaces also tend to be reflective, but that’s a different problem we’ll talk about on another post, so I’ve selected non-reflective subject and background for this post – a camera lens on a fabric background.
So, first let’s see how the camera is doing without our help – I’ve put the camera on a tripod with a remote shutter release, switched to Av mode and selected F/11 as the aperture because I want the entire lens to be in focus in focus (I was very close and F/11 gave me just under 9cm, or about 3.5 inches of focus) – this gave me a 13 (!!!) seconds exposure at ISO 400 according to the camera’s light meter and resulted in this image:
You can easily see the picture is both way too bright and way too pink, the brightness we expected but where did all this pink come from? to keep this a low budget production (I expect my readers are not pros with easy access to studio equipment) I’ve use a black T shirt as the background and while that shirt looks completely black it actually reflects much more red light then blue or green – especially with such a long exposure.
Let’s look at the histogram:
You can see the image is very bright with almost the entire image in the right side of the histogram, you can also easily see the picture is not as color neutral as we expect from a mostly black image with a little too much green and way too much red (you can also see by the small bump at the far right we have some over exposure, this is the light reflection on the top of the lens).
So, how do we know what’s the right settings for really nice black? the camera’s LCD screen does not help us here (since. like we said in last week’s post it’s brightness is way too inaccurate) and it’s hard to judge the difference between “nice rich black” and “way too dark” by the histogram – so I took 15 pictures at a third of a stop difference starting at the camera’s exposure and ending when the picture was very obviously under exposed and then checked the results on the computer (this is called “bracketing” taking multiple photos around what you think are the correct settings to make sure you get a good one).
For you enjoyment here is a composite of the center part of all those images:
The best image was the one exactly two stops darker than the camera’s meter (how wonderful – this is what was supposed to happen), and here is that photo:
And it’s histogram:
Now all that’s left to take care of is that horrible pink color, obviously the best solution would have been not to use a fabric with a red color cast to begin with – but I’ve decided to fix it in post processing instead, I’ve loaded the out of camera JPEG in the free paint.net and adjusted the color channels in the “Levels” window, I’ve then done another quick levels adjustment on the reflection in the top of the lens and got:
And the histogram:
Obviously I could get a better result if I used the raw file and loaded it into Adobe Photoshop or Lightroom – but I wanted to show you what can be done with two minutes and free software.
That’s all for today, next week we’ll take a break from black and white subjects and look at something else.