Sunday 16 June 2013

An open letter to Sam.....

Dear Sam,

 Thanks for an enjoyable day helping you sort out better ways of photographing cake decorations for use on your employers website.
 We talked at length about the need to get good,accurate colour, especially when dealing with foodstuffs. Below are sample pictures of your cake decorations done in my studio. The first example shows the finished picture with a bit of improvement in an image editing programme.
All of the colour looks correct. The back ground sheet is white paper that looks grey simply because there isn't a lot of light cast on it.

This is how it was done.
Most cameras come with a range of colour types built into the menu, usually they are depicted by small symbols that become visible on the screen on top or at the back of a camera. When initially purchased most cameras would probably be set to AWB (Automatic white Balance). As you can see from the examples
below this isn't always as accurate as it should be.This is the colour that automatic light balance produced. As you can see it didn't do a very good job of rendering the right colour as we see it. If you adjust the colour settings so that the daylight symbol (the symbol is the sun) is displayed you get this effect. Its even more orange.

Automatic Light Balance (AWB)

If set to shade  the picture is made even warmer as the camera tries to cheer up the added blueness in the light.

The  cloudy light setting is even more extreme.
Tungsten setting puts more yellow into the white of the flower
 Fluorescent Light (office or kitchen strip light) usually has a greenish/yellow quality.
Light balanced for flash

The next two types are Custom White balance and degrees Kelvin. With this first option you photograph a pure white target and set the balance to that, This is very useful in situations where you have a number of different coloured lights illuminating the thing you are trying to photograph. For example, daylight from a large window, strip lights on the ceiling and photographic lights directed at the object. Very tricky! Most photographers would end up trying to refine the white balance in Photoshop or a similar software.

You can also set the white balance with a colour meter to the appropriate number of degrees Kelvin. Hence the symbol is a letter K. To do this you would need a special meter. Very few professional photographers now use colour meters. Almost all would use Photoshop as its quicker and more accurate.

When working with small objects a lot of time can be devoted to propping the thing up in the best position to photograph it. I used some Climpex stands (you can just see the crocodile clip holding the flower) wire, masking tape,and BlueTack to hold things in place. A lot of patience and dexterity is needed.
 To focus, I used a home made bit of gear. A piece of a food carton with bar code on it that is easy to see and manually focus on through the camera lens. Its held in place by a funny thing intended to hold notes on an office desk. A camera that cannot be focused by hand isn't sophisticated enough for this type of work even if the maker says its automatic.
The card is placed in the group set back a little from the front of the flower, the camera is on a heavy tripod and then focused.  The card is removed from the view in the viewfinder and the picture is taken.
Even with a heavy tripod great care must be taken to ensure that camera shake does not occur during the exposure. I used mirror lockup and a cable release.

To refine the image I used Photoshop. Photoshop is a formidable programme that art students spend 3 years learning to use. You might be advised to try doing your colour balancing in a simpler piece of software. Many simple software programmes allow the colour settings to be corrected. Look out for 'colour balance' or often an image of a hyperdermic syringe is the symbol for the colour tools. You place this over a bit of your photo that you want to be pure white and then clilck your mouse and the colour should normalise itself.

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