All features / Drawing & coloring
Paint shading without leaving the outline
Alpha Lock confines colour, texture and highlights to pixels that already have content on the current layer. Transparent areas stay untouched, so a leaf or a hair shape keeps its silhouette while you work.
WORKFLOW
How it fits your workflow
One layer, one contour
Different from a full layer lock
Use a clipping mask if colour must stay editable
Practical details before you begin
Alpha is simply whether a pixel has content. A full layer lock blocks all editing, while Alpha Lock still lets you paint inside the existing shape.
It applies to the current layer only. If the brush seems dead, check that the active layer has visible content. The eraser is not restricted — duplicate the layer first if you need to protect the original.
PRACTICAL GUIDE
How do I shade inside a shape without painting over its edge?
Select the layer and click Alpha Lock in the layer panel toolbar. Once it lights up, strokes outside the silhouette never land on transparent pixels; click it again to turn it off. Good for recoloring hair, adding clothing shadows or changing an icon palette.
The brush suddenly seems dead. Is it broken?
Alpha Lock applies to the current layer only. Check that the active layer has visible content and that the marker beside the thumbnail is still lit — selecting the wrong layer is the usual cause.
What if I need to paint outside the outline?
Click Alpha Lock once more to turn it off. The eraser is not restricted, so duplicate the layer first if the original must survive. If the colour should stay independently editable later, a clipping mask is the better fit.
how to use alpha lock
Once locked, colour lands only on existing pixels, so no new colour spills outside the silhouette — ideal for recoloring.
STEP BY STEP
How to use it in the software
Alpha Lock: paint only where you already painted
What it does
Alpha is simply whether a pixel has content. With Alpha Lock on, the current layer accepts colour, texture and highlights only on pixels that already exist; transparent areas stay empty. This is different from locking a layer, which blocks all editing.
Four steps
1. Paint a solid shape, such as a leaf, on a regular layer. Do not pick the background or a folder.
2. Keep it selected and click Alpha Lock in the layer toolbar. The button lights up and a marker appears beside the layer thumbnail.
3. Brush shade, texture or highlights over the leaf. Strokes crossing its edge will not land in the transparent area.
4. To paint outside the outline, click Alpha Lock again to turn it off.
When not to use it
Good for: recolouring hair, shading clothes, changing an icon's colours, adding texture inside an existing shape.
Not for: painting outside the outline, enlarging the shape or adding a background — turn it off or use a new layer.
If you want colour and outline on separate layers so the palette can change later, use Clipping Mask (Feature 13).
Common mix-ups
Only the current layer is affected. If the brush seems dead, check that the active layer has visible content.
The eraser is not restricted. It can still remove existing content; duplicate the layer to protect the original.
Won't turn off? Select that layer and click the button again; a marker beside the thumbnail means it is still on.
STEP BY STEP
Feature 12 · Alpha Lock
Need exact settings and steps? Read the matching chapter of the in-app manual online.