GIMP tools - BDA

115
Mode
Description
appearance. The exceptions to this are a black layer, which
does not change the other layer, and a white layer, which
results in a white image.
Overlay
Dodge
Burn
Hard light
Soft light
Grain extract
Grain merge
Difference
Addition
Subtract
Darken only
This mode inverts the pixel value of the lower layer,
multiplies it by two times the pixel value of the upper
layer, adds that to the original pixel value of the lower
layer, divides by 255, and then multiplies by the pixel value
of the original lower layer and divides by 255 again. The
resulting image is a little bit darker, but not as much as
with the Multiply mode.
This mode is used to dodge any area of the image. For
example, a photo made in the darkroom to decrease the
exposure in particular area of the image, e.g. the face.
This mode is the opposite of the Dodge mode. It is used to
increase the exposure in particular areas of the image.
It is the best to demonstrate this mode by giving an
example.
This mode makes colours not so bright. It is similar to the
Overlay mode.
This mode subtracts the pixel value of the upper layer
from that of the lower layer and adds 128. It is used to
create a relief image.
This mode is the same as Grain extract, only it adds the
pixel values of the upper and lower layers together and
subtracts 128.
It is one of the most interesting modes, if you want to get
an unusual result. It is used to invert a certain element in
an image.
The pixel values of the upper and lower layers are added
to each other. The resulting image is much lighter.
This mode subtracts the pixel values of the upper layer
from the pixel values of the lower layer. Negative values
are replaced with 0. You get a lot of black in the resulting
image.
This mode compares pixel values in the upper layer and
the lower layer. The resulting image has a colour of the
smaller value. White upper layers have no effect on the