This icon on the Image bar opens the Image Filter bar, where you can use various filters on the selected picture.
Filter
Inverts the colour values of a colour image, or the brightness values of a greyscale image. Apply the filter again to revert the effect.
Invert
Softens or blurs the image by applying a low pass filter.
Smooth
Sharpens the image by applying a high pass filter.
Sharpen
Removes noise by applying a median filter.
Remove Noise
Opens a dialogue box for defining solarisation. Solarisation refers to an effect that looks like what can happen when there is too much light during photo development. The colours become partly inverted.
Solarisation
Specifies the degree and type of solarisation.
Specifies the degree of brightness, in percent, above which the pixels are to be solarised.
Specifies whether the pixels to be solarised are also to be inverted.
All pixels are set to their grey values, and then the green and blue colour channels are reduced by the amount you specify. The red colour channel is not changed.
Ageing
Defines the intensity of ageing, in percent. At 0% you see the grey values of all pixels. At 100% only the red colour channel remains.
Opens a dialogue box to determine the number of poster colours. This effect is based on the reduction of the number of colours. It makes photos look like paintings.
Posterise
Specifies the number of colours to which the image is to be reduced.
Converts an image to a pop-art format.
Pop Art
Displays the image as a charcoal sketch. The contours of the image are drawn in black, and the original colours are suppressed.
Charcoal Sketch
Displays a dialogue box for creating reliefs. You can choose the position of the imaginary light source that determines the type of shadow created, and how the graphic image looks in relief.
Relief
Specifies the light source position. A dot represents the light source.
Joins small groups of pixels into rectangular areas of the same colour. The larger the individual rectangles are, the fewer details the graphic image has.
Mosaic
Determines the number of pixels to be joined into rectangles.
Defines the width of the individual tiles.
Defines the height of the individual tiles.
Enhances, or sharpens, the edges of the object.