• A gobo can be used to fit on off-camera flash units •
A simple idea – but so useful!
A gobo is used to block or shape light – normally using black screens of some sort. They’re commonly used in the movie industry, and more recently photography. Find out all about them here…
Of light and shadow
It sounds like a grand and mysterious name. In fact the term gobo is a rather straight forward. Here is what the Oxford English Dictionary (OED) 
says…
gobo, (noun); gobos (plural)
Etymology: Unknown. Originally from the U.S.
1930 – Gobo, portable wall covered with sound-absorbing material.
1936 – A ‘gobo’ is a small black screen used to deflect light.
1970 – A gobo is anything that goes between, e.g., the light and the set.
OED (online) Seen 08/08/2013
So, this wonderful little word seems to have been a compound word from “go between”. Hmmm! I would like to see some proof of that. The side entry in the OED says in red “This entry has not yet been fully updated (first published 1972)”. Seems a long time without full qualification.
What is the Gobo really about? Manipulation of light and shadow. Our more technical definition in the Photographic Glossary (gobo) goes into more depth about how it is used in five broad ways in modern photography…
- To block light or create shapes or patterns of light and shadow together.
- A mask with a shape cut out of it fixed to the light and used to project a light shape (eg. a logo).
- Cards/screens to create shaped shadow or deeper shadow in a scene.
- A jury rigged light modifier on a light to shape or direct the light.
- A mask placed in the light beam which shapes the light/shadow in the scene.
- A light modifier allowing some light through and casts a specific shadow or diffusion shape
It is interesting that both the Hollywood studios and the OED use the term to manipulate and absorb sound. Of course in photography sound is less important. You can see however, that gobos are used to shape light and shadow in various ways.
How do gobos affect you?
If you have ever held your hand, a hat or a piece of card up to shade your lens to prevent flare or lens reflection you have used a ‘flag‘. Originally a gobo was the term used for protective devices to keep a lens out of incidental light. Now days the more specialist term, flag, is used for shield or blocking of light especially when it relates to the protection against lens flare. Understandable the two terms are easily mixed up. A flag seems to be used mainly for blocking light out. A gobo more for manipulating light, especially where that involves creating shadows.
Today I was photographing a white van in very bright overhead light. I keep a black blanket in my equipment for this type of situation. My assistant held up the blanket behind me to create a broad shadow across the corner of the van I was photographing to cut out the strong sun light. This is one form of gobo. It was not cutting out the light completely. I was reducing the very bright sunshine to an area of pure white so I could more easily pick out the details.
In a studio you might use a a black screen to intensify the darks in one area of a scene. It is a mood enhancer in this situation.
On another day I was working on business portraits. The office was a bright, but grey colour. We used plants on a trellis with a light behind it to create a shadow-pattern of leaves and diamond shapes onto the wall giving added interest to the background, breaking up the grey. This is a gobo too – being used to enhance the light/shadow ambiance.
More after this…
A solid light of the same colour and intensity across a still life is boring. Use cards or diffusion surfaces to vary the light and create slight shadows or graduate the light. One side of the still life use a black card to darken and block light. On the other side use white card to intensify and diffuse it.
A gobo is often used to shield the camera from light too, but it is not a flag. In A quick shoot using water? Tips to get you started… from yesterdays post a gobo could have been placed in front of a flash unit on the table. This would prevent the light getting directly back to the camera lens, but still project the light onto the back wall. A two in one gobo.
There is one further really fun use of gobos that is growing in photography. The recent growth of interest in light painting has renewed the interest in projecting shapes onto surfaces to be photographed. A black card with a logo or shape cut out of it can be placed directly in front of a light source. The light shining through the shape projects it onto a far surface. Then, in the dark, light painters can photograph the projection. Light painting is the intrepid art of photographing deliberately manipulated bright lights in the dark. It’s great fun!
What have we learned
A gobo is a term that describes the manipulation of the light shadow relationship. We use a range of blocking and masking techniques to manipulate the light and the gobos are the instruments of that manipulation. A flag on the other hand is a pure blocker of light.
Have fun thinking this one over. It is a useful concept and one that has infinite uses for mood, variation of shadow and creating settings.
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Photokonnexion Photographic Glossary – Definitions and articles.
Definition: Gobo (lighting)
Definition: Flag (lighting)
Light and Lighting – Resource pages on Photokonnexion
Definition: Lens flare; Flare (on a lens);
OED (online) Seen 08/08/2013
Honl Speed Gobo/Barndoor Black/White for Flash Gun (HP-DHS-SG)
Definition: Shadow
Honl Speed Gobo/Barndoor Gold Silver for Flash Gun (HP-GOBO-GS)
A quick shoot using water? Tips to get you started…
Definition: Source; Light source
Lastolite Gobo Set Nature (2613)
