Wednesday, 14 September 2011

Exercise - Contrast and shadow fill

The aim here is to use a still life together with a fixed light and various reflectors to show the effect of reflected light on altering the contrast and the shadow.
This exercise was done with a simple still life, a household reading lamp (60 watt) and various sheets of card. The f/stop and focal length were kept the same. All RAW images were processed in Lightroom 2, with the exposure as given by the camera, and the contrast set to +50.

Overhead lighting ISO 400, 1/6 sec

The initial picture was taken with the general room lighting and has a 'flat' look. The contrast and shadow are minimal.

Side light - ISO 400, 1/20 sec

Here the picture is taken with a relatively bright light source coming from the left. There is high contrast and a lot of shadow. The right halves of the pots have little detail. The creases in the cloth are very visible (and exaggerated by the shadows).

With diffuser - ISO 400, 1/13 sec

Here the lamp is used via a diffuser, the general look is softened, with less harsh shadows, however there is still very little detail visible in the right hand side. The exposure has had to be lengthened.

 I then experimented with the reflectors. The tablecloth was slightly straightened when placing the card in position. Nothing else was altered. The exposure remains as chosen by the camera's light meter, ISO 400, 1/20 sec exposure.

White reflector - far away - ISO 400, 1/20 sec

Here a white sheet of card placed about 1 metre from the arrangement has been used to reflect the light. Using a reflector has definitely increased the amount of light on the right hand side, although it is still slightly dark. It also seems to have had the effect of changing the colour temperature. I have deliberately not altered this in the post-processing.

White reflector - near - ISO 400, 1/20 sec

Moving the white card nearer to the pots has evened out the light slightly more. The shadows are now much more even.

Dull foil reflector -  ISO 400, 1/20 sec

On moving to using a silver reflector made of the dull side of kitchen foil, the contrast is increased again, although there is more of a reflection showing on the gold bands and handles. This is more obvious on a larger image.

Shiny foil reflector - ISO 400, 1/20 sec

The shiny side of the foil has reflected more light back onto the pots, with more of a glitter in the gold handle. The shadows are very definite here, possibly because even with reflected light the  cloth is remains in shade .

Crumpled foil reflector - ISO400, 1/.20 sec

There is little difference here with the reflector made from crumpled foil, although on close inspection the light is reflected onto slightly different areas of the pots.

The difference between the last 3 images is subtle and much more visible with a larger image. They would probably be much more obvious with a stronger light , as much of the light will have 'diffused' naturally across the length of the  set up (approx.2 metres). It would be worth repeating the exercise with everything much closer together or with a more powerful light source. The images with side lighting and contrast are much more interesting than the first one with the overhead light. 

In the images by Stieglitz and Weston shown as examples the shadow is essential to give definition to the faces, they would have been much less interesting without them.

Learning points:
  • side lighting can be much more interesting than overhead
  • a household light bulb has limitations!
  • diffusing the light can give a softening of contrast, without loosing it altogether
  • home-made reflectors with kitchen foil do work
  • the distance between light, subject and reflector is important.

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