Concept of Selection

Selections

> A selection is a region of pixels defined from the user to let any operation to be applied only to the selected pixels. Selections can have any shape, even very complex and irregular, and can be created with a variety of tools in Focus Photoeditor.

> 1 bit and 8 bits Selections: differences

> The basic selection contains only the information where to apply changes and where not. This information can be represented by only two numbers 0 and 1. So if you are outside the selection the value will be 0 and no pixels will be affected, when you are inside the value will be 1 and all pixels will be affected by the same amount of change. This is called 1 bit selection. But Focus Photoeditor supports also 8 bit selections, that means that if you are inside the selection pixels can be affected by different amounts of changes, depending from the level of the selection that can range between 0 and 255.

> You dont need to convert between 1 bit and 8 bit selections, Focus Photoeditor will do it automatically when necessary.

> Let's look at an example to create a 8 bit selection with a feather. A feather is a region on the borders of the selection that has values between 0 and 255. This kind of selection can be useful when you want to avoid a sudden discontinuity between the region inside and the region outside the selection.

> Example of Feathering:

> Let's use the magic wand tool to create a selection on this picture: click with the magic wand tool on a point of the face:

> Now the selection is equivalent to a 1 bit informations region. It means the pixels inside of selection are all completely selected at same way (of same amount) and those outside are all not selected.

> So if we apply for example a color filter we get the result in the right picture:

> As you can see there is discontinuity between the pixels where the filter has been applied and those where it wasnt. To avoid this discontinuity let's apply a feather to the previous selection: from main menu choose: Selection->Apply Feather..

> And choose a value of 4 for the size of the feather. The selection will become automatically a 8 bit selection.

> Let's apply the same color filter of before to this selection. We can see now that the transition between selected pixels and unselected ones is much smoother than before.

> You have to learn to be familiar with this technique, because many retouch operation may require smooth transitions between regions where the changes are applied and regions where they arent.

> Other Ways to create 8 bit selections:

> Tools to create selections that have an amount or opacity option can be used to create 8 bits selection. For example Geometric Drawing selections can be more or less transparent, that means the pixels will be more or less selected.

> Also Importing a selection from a picture file (when in grayscale mode) creates a 8 bit selection.