Club notes 8 – Selecting round a complex picture with hair

Selecting round a complex picture with hair

The problem set this week was to remove the background from a photo of a composite picture.
Whereas most of the outline was straight lines, there were somecurves, some of the picture was difficult to distinguish from the background and some consisted of woolly hair.
This meant that a single approach would probably not work, so ...

• Duplicate the Background layer and then hide it, work on the new Layer 1 (Ctrl + J).
• Filter | Extract
• Use the highlighter to draw round the edge where you want to mark the limits of the extraction. Try to straddle all areas of the interface without leaving any gaps. It is a good idea to use the smallest brush consistent with completing it in a reasonable time.

I have since noted that straddling two contrast areas, such as the boots at the bottom of the picture does confuse the automated extraction somewhat, in a later attempt I used a finer brush here with rather better results.

• Use the Fill tool (B) to fill the part of the picture you want to keep.
• Click on OK

This will be a partial success, but if some touching up is required, use the History brush

• Make sure the History brush icon is on the LHS of the Open in the History palette. This is where the History brush will collect pixels from in the next step.

• Use the History brush (Y) to tidy up round the edges, painting in the original content of the picture.

Note: as with all brushes and erasers (including the extract filter above); click on a point, hold down the Shift key and click on a second point paints a straight line.

At this stage, don't worry too much if you are a bit over enthusiastic. Now to do the final tidying up, but in a non-destructive mode so that it is easy to keep correcting any slight errors.

• Click on the Layer Mask button at the bottom of the Layers palette to apply a (clear) layer mask.
• Select the Eraser tool (E) with a round hard edged brush
• Make sure the Default colours are selected (D)
• Erase where you have gone over the edge.
• If you over correct, Swap the foreground and background colours (X) and paint the back again.

Note: you can use either the Eraser or the Brush tool to do this.

• With the Brush tool Black foreground masks (hides) the picture and White unmasks (reveals) the picture.
• With the Eraser tool White foreground masks (hides) the picture and Black unmasks (reveals) the picture.

Note: When working with Masks; check you are actually working on the mask! Look the mask icon in the layers palette on the right here, it has an extra line round the mask icon's corners.

Compare it with the picture below where the image icon has the extra line round its corners, if this is the case you are working on the picture not the mask.

Next month (October 21) we will re-visit April's exercise, patching up an old, torn photograph.