Quick and Easy Canvas Extension

August 2nd, 2010 by Richard Peters

This week we're running a series of workflow tips by pro photographer Richard Peters.  Check back each day for a new tip!

Ever had one of those shots that ‘almost’ worked but the framing was just off? Or you wanted to clone out a small distraction near the edge of the frame but there was too much detail to try and match with the clone stamp? Well here is a very quick and neat way to add in some extra canvas, and fill it with original picture information so it matches the rest of the image perfectly. It takes 30 seconds and requires no fiddling with the clone stamp and paint brush – which also makes this technique ideal for Photoshop beginners as well as more advanced users.

Before and After canvas extension

Before and After canvas extension

Ok, so the base image I am using for this demonstration is a little tight in the frame but it’s nice enough and serves as a good image to do this quick tutorial with. It’s a simple duck swimming across the water, however, I ran out of room to pan and so caught the duck too far to the right of frame so the composition isn’t ideal. The image would of course look better if the duck had a little more room in front of it than behind. The way a lot of people would tackle this is to extend the canvas and use the clone stamp and paint brush to try and put some detail back in the shot. This method is fine if you only want to touch up a plain area, but, as soon as you start needing to add in area’s that have some detail or a variation in light/colour change etc…well, things can start to get fiddly and time consuming as you try to match the old canvas with the new…but without having duplicate area’s of detail or patches of light and dark that don’t flow together well – the tell tell sign of a rushed clone job.

With this image there are some texture/ripples in the water and although they are quite simple I don’t really want to have to spend time trying to clone them. So, let’s see how I quickly gave the duck a little more space to swim in to, whilst still retaining the original texture and ripples in the water just in front of the duck.

Original Image

Original Image

Step 1: Extend the canvas
The first thing I want to do is extend the canvas so I have some room to work with. Originally I suggested the old method of going to Image – Canvas Sizeand entering the new measurement in the Canvas Size box as per the image below.

Adding Canvas

Adding Canvas

However, I have since been told about a faster way that I didn’t know about (many thanks). So now I will do it this way, first select the crop tool and make sure the dimensions boxes for it are blank as per the diagram below.

Blank the Crop dimension boxes

Blank the Crop dimension boxes

Then, draw a box around the outside of the image…

Draw a box over the whole image with the crop tool

Draw a box over the whole image with the crop tool

Then, simply grab the far right, middle anchor point (little square box) and drag it across to the right as far as I want my new canvas to extend.

Drag the far right anchor point as far as you need

Drag the far right anchor point as far as you need

I finally hit enter and I have an image that looks like the one below. It’s the original image with a nice big black bar at the end (it could also be white, it doesn’t matter what colour you choose when you extend the canvas). This is usually the point when you might think about heading for the clone stamp tool…instead, here is the clever bit to this method…

Image with new canvas

Image with new canvas

Step 2: Make your selection
Instead of cloning some of the image on to the new bit of canvas, we are simply going to use some of what is already there and stretch it across a little. To do this I need to first make a selection of the area I want to extend across, and I will do this with the Marquee tool – which looks like a square made up of dotted lines. It can be found top left of your tool palette in Photoshop.

The Marquee tool

The Marquee tool

Now, what I have done is highlighted the area I want to stretch, there isn’t much space to play with as the duck is so near the edge of the frame, but there is just enough to make a usable selection.

Top Tip: The bigger the area you can select to stretch the better as if you stretch a section of image too far it will start to pixelate, so keep an eye out that you don’t take things too far.

Making the selection

Making the selection

Now I want to copy that selection and paste it in to a new layer, so I hit CTRL C on the keyboard to copy, followed by CONTROL V to paste it on to a new layer. It will appear in exactly the same place on the image so at first glance you might think there is nothing there, but a quick look at the layers palette will confirm it is.

TOP TIP: Hitting CNTRL J on your selected area will automatically copy and paste to a new layer for you, if you want to speed things up even more!

Selection in own layer

Selection in own layer

Step 3: Extending the selection
Ok, so now I have made the selection and copied it to it’s own layer. Next I want to stretch it by going to Edit – Free Transform in the drop down menu at the top of the screen or by hitting CTRL T on the keyboard.

Transform menu

Transform menu

The selected area now has six little boxes around it, these allow me to drag the selected area in any direction. I want to click and hold on the right hand side middle one and pull it across to the right – not too far but just enough to give the duck space to swim in to.

Top Tip: You can drag the box in any direction using the little squares, so you can stretch your selection in diagonals too if you need, not just in straight lines.

Selection ready to stretch

Selection ready to stretch

Once I have stretched as far as I need, I hit enter to confirm the transformation and turn the transform function off.

Selection stretched

Selection stretched

And that’s it, all done! Now all I need to do is flatten the image (Layer – Flatten Image) and crop to taste. The whole process takes about 30 seconds from start to finish and gives a much cleaner look than cloning does as you’re using picture information that is already there so it looks natural.

Finished Image

Finished Image

Another Example
In the image below of a Great Spotted Woodpecker. The background went to a dark green above the woodpeckers head and even after I cropped in a little I was left with a small, distracting line at the top of the frame – as you can see on the left image. Rather than crop in even tighter or mask the tree out and try to clone over the dark area, I simple extended the canvas up a little and stretched the section just below the dark patch. It was only a small change but the result is a cleaner looking image. This is the only decent image I have to date of a GSW so I was happy making this small change, until I take a better one.

Small upwards extension

Small upwards extension

There will always be exceptions to the rule of course when this technique does not work. However, next time you need to add some canvas or crop something small from near the edge of the frame, give it a try. Just remember, keep it fairly simple, if you have to go adding huge great chunks of canvas the chances are you should be taking the shot again! This method, like all processing, works best when only used in a subtle way.

Final Thought
I see removing elements from a photo or altering the shape of content within it, in a different way to levels/saturation etc which is just enhancing what is already there and not removing or distorting it. I don’t frown upon anyone who edits pictures in any way, each to their own. I just look upon my own images from the eyes of most of the major photography competitions rules, in which a photo edited in the way shown above would not be eligible for entry – so I don’t make a habit of doing it too often.

That said, it is a great method for saving an image for other use that might otherwise have been destined for the bin!

Learn more about Richard, read his articles and view his videos on his blog:  Richard Peters Photography Blog

Check out Richard's  YouTube channel for great video content, and follow him on Twitter.

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