Black background post processing tips?

Question

This week I've been experimenting with getting some things photographed with a completely black background. Following some tips on this site about background distance etc, I came to the following set-up:

Getting the lighting right was quite a challenge, and in the end I had to reduce exposure almost a full stop in the camera to avoid blown out highlights. The results however, needed quite a bit of post processing - exposure, white balance, saturation... My subject matter were a few flowers. Here are some of the processed results:

Large JPEGs are here, here, here and here. Original RAW files are here, here, here and here.

My question, given the results, is this: What can I tweak on my set-up, camera settings or post processing to keep the black background, but give the flowers a bit more punch. How would you process them?

Looking at the comments and answers so far, I think I'm looking for a more 'high key' look for the flowers, but want to keep the background black still.

Answer 1

A large part of the problem is that you are essentially using only a single, relatively hard (small and non-diffused) light source. That sort of lighting can create very dramatic pictures, but not of the sort you are trying to shoot here. You want colour across most of the petals and leaves, but the only light the bulk of the flower is getting is reflections from walls and a ceiling that are too far away in relation to the main source. That, in turn, means that specular highlights are going to blow out long before the "body colour" is established. To expose properly for the highlights (as very high highlights) under those conditions, the flowers themselves will be extremely dark. Dramatic, but more in a filme noire sort of way rather than a textured flowers sort of way, and that's probably not what you want.

The only change you need to make, really, is to put a large-ish reflector just about where the camera is in your setup. (Above the camera, of course, not in place of the camera.) A couple-three-four square feet of white fomecore will work wonders, pumping enough light into the scene that the highlights will be much lower in value compared to the main values of the flower and foliage. It will not be strong enough or hard enough in relation to the main light to create cross-reflections or any other obvious "I stuck a light there" artifacts, so you'll still get dramatic textures and deep shadows. The only change will be that your highlights and the rest of the image will fit into the same exposure.

Answer 2

Your lighting has a lot to do with this, I believe. It looks like you were using continuous lighting here, which has the advantage of being easy to preview and meter, but won't deliver a lot of lighting power relative to inexpensive strobes. I recently shot an Iris outdoors during the day, and I was able to darken the background almost completely by severely underexposing the scene, then adding a strobe at close range (I was shooting Manual, but you might be able to achieve results like this with TTL metering).

As you can see, the strobe adds some highlights and shadows, which give the flower some dimension, and the water droplets add a bit of interest, too. Be sure to soften the strobe somehow to avoid overly harsh shadows - in this case, I used a mini softbox. Below, you can see a bit of the setup for this shot:

Yes, I ended up switching the strobe to camera left for the photo that I wound up keeping, but the overall setup is the same. Note that by using powerful lighting at short range, I was able to so underexpose the background that it darkened nearly completely, even though it was still quite light out (as seen in the setup shot). With your dark background, you shouldn't need anywhere near this amount of overpowering artificial light -- I did this mainly to demonstrate the technique.

As far as post-processing goes, I used Lightroom to process the photo -- I boosted blacks just a bit to completely drive out the remaining traces of the background, then sharpened a bit. You can certainly play with processing to add more "pop", but the closer you can get in-camera, the more authentic the end-result, in my experience.

I wrote this shot up on my blog, by the way, including a second Iris shot done with a white background and more of a high-key look -- again, mainly to illustrate how to control the look of your background using strobes.

Answer 3

Without knowing exactly what is meant by

"...a bit more punch."

it is hard to say exactly what you need to do to get that look.

After playing around with the fourth photo for a while using Canon's Digital Photo Professional, here are my impressions.

• Composition could be stronger. The first one is alright, but the rest are confusing, at least to my eye. None of the lines created by the subjects as placed lead the eye anywhere.

• The background is still a little too bright. A lot of the things I would have liked to have tried in PP using only global adjustments I could not because it raised the level of the background out of pure black. Either use a more light absorbent background material, shade the background from your key light, or place it further behind the subject so that the inverse square rule has more of an effect. You could use a brush tool to mask the background in LR or PS, but that is usually very time intensive. Why not just kill the background better when you shoot the scene? And the reflections off the glass of those picture frames isn't helping the dark background any, either.

• A very soft fill light opposite the key (to camera right and low enough that none of it spills on the background) would help soften the shadows on the plants so that killing the black background in PP doesn't also kill the shadowed parts of the subject. You don't need, or even want, to eliminate the shadows but you do want to soften them a bit.

• Noise reduction and sharpening are critical. Even at ISO 100, the dark areas have some very fine noise, most of it chrominance noise but there is a little luminance noise as well. In DPP I used a setting of 2 and 5 respectively to reduce the noise.

• Even with a single RAW file, consider the use of an HDR tool as a way of enhancing detail. The letters HDR don't necessarily have to result in an image that resembles a rainbow of technicolor vomit. Getting the NR right before you tone map using an HDR tool is important or the detail enhancement will also enhance the noise. The same applies to making the background darker when you shoot the scene. The obvious next step would be to take a series of exposures at, for example, -2, 0, +2. This will allow much better results in terms of noise in the black background.

• Here is what I came up with. Just by cropping to create diagonal lines between the subject and the frame, in my opinion, added a lot to the image. I'm not entirely happy with the way it worked out at the bottom of the frame, but I couldn't rearrange the flowers/camera position and shoot it over. :-)

Here are the settings used in DPP's RAW convertor.

Here are the settings applied to the RAW file using DPP's HDR tool.

Answer 4

I would try back lighting the flowers with an off camera flash and putting a fill flash on the other side from your key. Generally, the punchiness that really makes it stand out from the background is accomplished with back lighting which tends to make the edges more pronounced and give more "pop".

This could probably look kind of weird with the strong shadows that your key light is throwing though, so that is why you would want a fill light to make the shadows still present but softer.

You can get more information about this if you read up on 3 point lighting. The Key is the main light, the Fill is a secondary light that fills in the shadows made by the key some and the backlight is the one that is behind (and typically below) the subject to light up the edges.