Cut and Paste – Frank Thomson

On Monday 13th Feb, I tried to demonstrate cutting and pasting. This proved more difficult to present in the time available than I had anticipated, so I have modified part of the demo to show more clearly what was happening.

The objective was to:-

Use an image of the National Museum of Art in Washington DC which I took on Kodachrome with a Zeiss Ikon Contaflex in 1959.

Washington DC National Gallery of Art

Cut out 2 characters from a photograph taken at a Folk Festival in Switzerland in June 2011 with a Canon 40D,

Swiss Folk Festival characters

And paste into the first image

Take me to your fine art museum

The idea was to depict two aliens seeking for the Fine Art Museum rather than “Your Leader”

As a first step open both images in Adobe Photoshop CS5, and then drag the character image onto the background, where it automatically becomes a layer. Next select the characters using the Quick Selection Tool, and, to improve the selection, use the Refine Edge option. The last stage is to use a scale transform to make the characters of a suitable size and move them to the desired position. As the light is coming from behind the photographer, the result looks reasonably “realistic” without the need for further work creating shadows.

To demonstrate more clearly the various aspects of the Quick Selection tool and Refine Selection Edge option, I am going to make the cut-out on a small area with some fairly sharp edges, some fine hairs, some coarser fur and some colours in the foreground very similar to the background, which makes it more difficult for the selecting algorithms.

Ready to start quick selection

I clicked on the Quick Selection Tool from the toolbar, and ticked Auto-Enhance. I checked that the Sample All Layers option was not ticked, as I want to concentrate on the one layer.

Result of quick selection

I have used a blue coloured Quick Mask (the bottom button on the toolbar) to show the result of a first pass with a larger brush, and a second one with a small brush to refine the smaller areas. Pressing the Alt key changes to an un-select brush, so unwanted selections in the first pass can be removed by brushing over them. The aim is not to select the hairs etc at this stage, to allow Refine Edge to do its stuff in selecting the finer detail.

I am now ready to use Refine Edge. This is to the right of the Auto-Enhance in options bar. This tool looks rather complicated, and it is certainly true that I have had to experiment with the various settings to get the desired effect.

Start of cut and paste

First choose the View Mode. Press the F key to cycle through the 7 options to choose the current best one. The On White one shows that my quick selection is lacking fine detail. Now decide on the width of the edge to be detected. This is called the Radius. A large radius is good for hairy detail, a small one for simple edges, so Adobe provide a Smart Radius facility that automatically adjusts the width of the radius for hard and soft edges in the border region.

There are various options to use to get closer to the desired result:

1. Smooth reduces the hills and valleys of the selection border to create a smoother outline. While this is good for the simpler edges,I did not want much of this as I did not want to smooth the hairs.

2. Feather blurs the transition between the selection and the surrounding pixels border and the smoother outline, so in this example I did not want much.

3. Contrast With increasing contrast, soft-edged transitions along the selection border become more abrupt. I suspect I used too much, and would have been better with the Refine Radius tool.

4. Shift Edge moves soft-edged borders inward (negative) or outward (positive). It can help to remove unwanted background colour from selection edges. I did not uses this control

The button on the left below the move tool is the Refine Radius tool. Brush over soft areas to add fine detail to the selection. This is very useful for fine tuning the selection by brushing over the hairy regions. (Press ALT and brush to use the Erase Refinements tool to back out).

With 'show radius' turned off

When painting with the Refine Radius tool on a Black background, I could see the effect of each brush stroke and if there was any colour fringing with background colours.

Decontaminate colours gets rid of any residual colour showing through from the red and blue striped shirt in the background.

Output can become a selection or a mask on a new layer or document. I wanted my output to be the original character image with a layer mask. This meant that I could modify odd bits where too much was showing, by painting with black on the layer mask.

Layers showing layer mask

Note that it is also possible to apply Mask Edge to refine the edges of a layer mask, but that is for another time.

Now to see the cut out characters’ fur pasted onto the 1959 background.

Final demo cutout

I suspect that I could improve on this with a bit more experimentation, but then is there enough time in life for this?

Adobe offer a video at

http://tv.adobe.com/watch/learn-photoshop-cs5/using-improved-selecting-and-masking/

which shows to process of selecting a model with flowing hair from a plain background. It lasts about 12 minutes.

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One response to “Cut and Paste – Frank Thomson

  1. I think Topaz Re-Mask or OnOne software’s Perfect Mask does it easier.

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