The Gamma Window is used to change the tones and colours within a design. It can be used in several ways to increase or decrease the tones in the whole design as well as within selected areas. This article focuses on how to use the Gamma Window to adjust and manipulate the tones of separated layers.
When you open the Gamma Window, you will see a diagonal line on a grid. The diagonal line represents the tones in the design. In the image below, the Pipette Tool has been used to click on a tone on the separated layer. A vertical line appears in the Gamma Window when you do this, and this indicates the level of tone you have clicked on. If you click where the vertical line intersects the diagonal line, this places a node on the diagonal line, and the level of tone is then displayed in the top left hand side of the window.
This node can now to moved to change that tone. In the example below, we have dragged this tone down to 15%, and this is indicated in the dialog box in the top right hand side of the window.
As we have pulled down the tones, you will notice all the other tones have reduced too. This is because the diagonal line is in Curve Mode. Curve Mode allows for smooth transitions between each tone. If you want to push these tones back up, simple click on the diagonal line again to add a new node, the push the curve upwards. The level of tone you are adjusting is displayed in the dialog box in the top left of the window, and the tone you are changing it to is displaying in the top right hand side of the window.
Curve Mode and Line Mode
The Gamma Window gives you the choice to edit the diagonal line in Curve or Line Mode. When you use it in Line Mode, you have to move several points on the graph to make it bend in a smooth curve. The Curve Mode automatically gives you a smooth transition between nodes. The curved line is the default setting, but if you prefer to work in line mode you can change it through the contextual menu.
- Hold down ^ (control key) and click inside the Gamma Window.
- Select Line to change the curve to a line.
If you wish to set the line mode as the default instead of the curve, go to AVA Menu > Settings , and under the General section make sure ‘Start gammas in line mode’ is switched on.
Note: Any previously saved curves will open in the mode in which they were saved. For example, a curve saved in curve mode will open as a curve, even if the preference is switched to line mode.
Colour button
The colour button, switches between showing curve in the layer's colour and black. It's useful to see the curve in the layer colour to help identify which layer's curve you are editing, but if the layer is a light colour you might want to switch it to black so it is easier to see the curve, see example below.
Above you can see we are adjusting a magenta and a light green layer, but it is not easy to see the curve for the light green layers, below I clicked the Colour button to switch to black mode, now the curve is easy to see and adjust.
Pipette Plus Button
The Pipette Plus Button allows the user to click on a point / tone on a layer then by moving the cursor up or down increase or decrease the tonal density.
To use this:
• Choose the Pipette tool from the AVA tools window.
• Go to Edit > Gamma and click the Plus Pipette button.
• Click and hold down on a tone that you wish to adjust, then move the cursor up to increase the tonal density or down to reduce. You can release and click another point if required.
• Once you are happy with the tones click Do Gamma to apply.
See Movie below,
This is a nice way to adjust the tones without having to look at the actual gamma curve you are creating.
DeleteLight, Mid and Dark Pipettes
Selecting these, then click in the design well set the tone in the place clicked to either 0% tone, 50% tone or 100% depending on which pipette you have selected, with the Pipette tool selected.
If you choose the first pipette 'Light Point', then click in the design the place you click will become 0%, this is good for clearing noise from a scan in areas where you want to be clean / white.
If you choose the second pipette 'Mid Point', then click in the design the place you click will become 50%.
If you choose the last pipette 'Dark Point', then click in the design the place you click will become 100%, this is good for making sure the darkest areas in your separation are 100% density.
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