Cut out glass in gimp - how it works

In this practical tip, we not only show you how to cut out a glass in Gimp, but also how to place it against a different background.

Optional glass in Gimp - so it'll work

The problem with cropping glass is the transparency of the object. Simply cutting out is not enough here.

1. Open the image in Gimp and cut it out. The lasso tool is best suited for this. If you are not yet familiar with the freeing of objects in Gimp, you will find a small tutorial in this practical tip.
2. Once you have cleared the object, copy it to the clipboard with "Edit"> "Copy".
3. Open the new background you want as a new layer. The easiest way to do this is via "File"> "Open as layers".
4. Create a new transparent layer and paste the copied glass from the clipboard via the menu "Edit"> "Paste". The glass is inserted as a floating layer. Therefore, right-click on the floating level to open the context menu. Here you select "to the new level".
5. Duplicate this new layer with the cut glass. In normal mode, you leave the lower of the two glass layers in the layer window, but reduce the opacity to about 50%. At the upper glass level, set the mode from "Normal" to "Multiply".
6. Make sure that the upper glass level is selected and navigate to "Colors"> "Curves". "Value" should be preset as the channel here. Now drag the curve far into the upper left corner. Play around with the curve a little until you get a satisfactory result.
7. Now switch back to the lower glass level. The glass is still too dark, it still needs to be lightened. To do this, open the "Colors" menu and select "Brightness / Contrast". Move the slider from "Brightness" to the right until a realistic brightness of the white glass is reached. Now the glass should appear bright again, but the background should shine through realistically.
8. Tip: There is an alternative way to crop glasses in Gimp. This takes a little longer, but a more realistic effect.