Free-form select

Exemption means in photography, prepress and in computer graphics, the liberation of a motif of an interfering background; the mask for cropping an image is called in the jargon usually a Cut. Also in the print media a " detached house " without reference text on the same page is called " Cut ". It is often then referred to it in the following text.

Applications

Cropping may be required for various reasons. The most important are:

• It should be ensured that the viewer is not distracted from the background and other accessories; it sometimes finds the partial Cropping. In this case, insignificant areas of the image can not be brought completely to disappear, but only attenuated (contrast reduction while increasing the brightness similar to the Highkey Photography), to obtain the context of the motif and at the same time to draw the attention of the recipient.
• One would like to provide raw material for photo montages, the subject should therefore be inserted in any new composition, one reason why Cut in advertising play a paramount role.

See also: Photo agency, advertising photography, product photography.

Techniques for recording

There are several techniques of placing free. The first is to use a mostly pure white and free of shadows lit background during recording. In the dark-field recording, however, the subject is positioned on a well -reflecting the illuminated glass plate or the like on a matt black lined or painted box, tub lies. This gives the impression that " float " on the subject while away black background (like a star in space ).

Traditional techniques ( analog photography )

For photos that you want to release later, common techniques of retouching then required in the conventional photo lab include

• Masking (sometimes also comes during the recording for use; everyone knows the keyhole or binocular images from films that are intended to indicate that a player just has that look )
• The Dodge
• Attenuating unwanted or superficial areas with appropriate chemicals (see Farmer shear attenuator )
• The free parking mask is manually cut on the light table after the photograph of a Masking or drawn with red chalk.

The simplest method is the one that prevails at the interface assembly: the subject is carefully cut, mounted on a pure white background (glued) and photographed again (see reprophotography ). In photography, large objects, the object is positioned in front of a fillet, also to avoid disturbing space lines.

Electronic image processing

In the electronic image processing different tools for masking used, which is used to select areas of the image to be deleted. The most important of these are:

• Of the wand and the Chroma-/Farbmaske for automatic masking (same color areas are masked within a selectable tolerance threshold). However, this automatic method is relatively imprecise, especially when shooting backlit against white background, the object is often masked unintentionally.
• The Lasso for freehand masking (in some programs decidedly Freehand mask called )
• Masking by award shapes ( circle, square or rectangle and ellipse )
• The path (created with the pen tool ). Similar to the lasso, but any shape can be accurately traced. For example, to trace a circle, in contrast to the lasso fewer points are needed. While using the lasso only straight lines can be set or the Lasso automatically conforms to an object, which ultimately leads to a square or inaccurate masking paths can follow every contour precisely because the individual routes can be rounded. The pen tool works here, like in Adobe Illustrator, using the principle of the Bezier curve. The great advantage of the compound path is that you can select it in hindsight and over again and also correct. The path remains even after saving in JPG, TIFF, and PSD.

Then the masked parts of the image are replaced with the paint bucket tool by a desired uniform color (usually white or black ), or is the background removed.

Other meanings

With free sites you used in photography and the image design technique, a sharp image through targeted use of the depth of an object against a blurred background. For this purpose, it is advantageous to use particularly fast lenses and longer focal lengths.

See also: Tabletop photography, blue screen technique ( blue box while watching TV )