Friday, February 25, 2011

Creating Composite Images - 24 Feb 2011

Ok, Dawn, this one's for you.  I've had a number of inquiries as to how I've created the composite images I tend to post on a semi-regular basis.  So I thought I'd prepare a detailed tutorial so that anyone can do it.  The following is my workflow, and it may be different from the way others do it, but it works for me.

First off, the reason I like to create composite images is to show a bird (usually in flight) at various positions in its flight so that I can see diagnostic wing features that a single image may not necessarily show.  With the D300 and MB-D10 battery pack I'm able to shoot 8 fps, which is great for capturing most birds-in-flight.  The camera is fast enough to capture wing positions in up and down positions, as well as fully-extended. This is important if one is looking for the patagial bars on a Red-tailed Hawk, or the black armpits of a Black-bellied Plover in basic plumage.  With my old D70 (6 fps) it was commonplace to capture 3-4 frames in a row with the bird having the same wing positions (as if it were soaring), since the bird was flapping its wings at roughly 6 fps.

So, my workflow consists of opening (in this case) 3 images of a sequence in my post-processing software (Photoshop CS4), copying the bird from 2 of the images and pasting them into the 3rd as 'Layers'.  Using the 'Move' tool the birds can be positioned next to each other so that the final image can be cropped (if necessary) to give that full-frame appearance.

Let's start with opening three images of sequence.  This Rough-legged Hawk was lifting off from its perch, so it was much easier to capture three consecutive frames as it lumbered into flight.  I'll use the left-hand image as the anchor image, as it is closest to the perch and leaves just enough room for two more birds.  I'll highlight the birds from the remaining two images at right and paste them as layers into the first image.

I'm using Photoshop CS4 to perform the following steps.  However, any imaging software that allows you to 'highlight', 'copy' and 'paste' will work.  Image Mode should be set to RGB.

In Photoshop, use the 'Magnetic Lasso' tool to highlight the hawk in the 2nd image.  This tool is great because the line will 'snap' to the edge of the bird as you 'draw' an outline of the bird so that only the bird is highlighted.  If you were to select a portion of the gray sky background and paste it into the first image, then you have to adjust contrast/brightness so that the backgrounds blend in.  The magnetic lasso tool helps eliminate this step.

Select the 'Move' Tool and place the pointer somewhere inside the highlighted area.  The arrow will change to a 'pair of scissors' indicating that you're now able to left-click w/ the mouse and 'drag' the hawk from the 2nd image into the 1st image.  Once you drop the hawk into the first image, it will be inserted as a new layer (with the 1st image now the 'background' image).  With the Move tool still selected, you can move the hawk anywhere over the background image.

Now use the Magnetic Lasso Tool to highlight the hawk in the 3rd image.  Select the Move Tool, place the cursor within the highlighted area, then click and drag the hawk into the 1st image.  It will now be a new Layer floating over the previous Layer and Background.

We now have the original (1st) image with 2 Layers.
Before we do any further editing of the composite image, we need to 'Flatten' all of the layers, or combine them into a single, editable layer.

From the menu bar, select 'Layer' then 'Flatten Image'.  We're now ready to continue editing (adjusting brightness/contrast/color, etc...).

If you look at the image at this point you notice the birds are a bit too close to the left edge of the photo.  The tree on the right makes a nice background feature, but the birds are currently 'exiting' the image, so I want to 'move' all three hawks to the right so that they are closer to the tree and centered more in the image.

First, I'll select the 'Lasso' Tool and draw a loose outline of the birds.  I'll then select the 'Move' Tool and drag the three birds to the right toward the tree.
In the process, however, I've exposed a white background that now needs to be removed.

Simple enough.  Use the 'Magic Wand' tool, and click inside one of the white areas of the background.  Hold down the [Shift] key and click on the remaining three white areas so that all of the white areas are selected.

With the white areas highlighted, select the 'Eyedropper' Tool and click on any portion of the gray sky background.  This will copy the color to the 'foreground' pallette shown at the bottom of the tool bar at left. 

Go up to the menu bar and select 'Edit', then 'Fill'. Select 'Foreground Color' from the window with Blending Mode 'Normal' and Opacity at '100%'.
Use the 'Magic Wand' Tool to deselect the now-filled highlighted areas.  The image background should now be a uniform 'gray' color.

Which leads us to our next issue: the image is still dark and a bit dull (colorwise).  No worries.  Go up to the menu bar, select 'Image' and then 'AutoTone'. The program will now auto-adjust brightness and contrast and give an image that suddenly pops!

In some cases, however, the image may show too much contrast.  So, go to 'Image', 'Adjustments', select 'Curves' and drag the diagonal line to the left just enough brighten the image. A slight drag of the bottom left corner of diagonal line will reduce contrast.  Go to 'Edit' and 'Undo' if you're not satisfied w/ your efforts, then go back to 'Curves' and try again.

Lastly, a couple of touch-ups.  Go to 'Image', 'Adjustments', select 'Hue/Saturation' and bump the Saturation slider to the right just a bit to add a bit more color to the hawks.  In this case I wish to bring out a bit more 'yellow' in the underwings that help to ID the bird as a juvenile.

Finally, lets sharpen the image to make it ready for printing or for the web.  Go to 'Filters', then 'Sharpen' and select 'Unsharpen' Mask.  This allows a bit more flexibility in sharpening images than just the 'Sharpen' or 'Sharpen Edges' Masks.  Amount is usually adjusted between 50 - 100%, and Radius is adjusted between 0.5 - 2.0.  In this case I left Amount at 50% and moved Radius to 2.0.  Too much sharpening, however, can put halos around high contrast edges, so use with care.

Save the image as a .TIF.  In this case I labeled it 'RLH.Tif'. 
Then, for posting to the web, 'downsize' the image (in this case it is 4288 x 2848 pixels) to 800x600 pixels and save as a .JPG with Compression set to 8-10 (out of 12 max).

We're done.  See First Image at beginning of article!

1 comment:

dAwN said...

Thanks Jerry! So very kind of you to post's allot of work!
I don't know if I will every have a DSLR that would allow me to take such beautiful flight shots. I suppose I could use this technique for a turtle..Hee hee..
Thanks again Jerry! I am passing this along.

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