In response to several requests for more technical information to be provided as part of Canberra Photographic Society activities, we have started a new technical session to be conducted at the start of each Workshop evening. Members will take it in turns to spend 15-20 minutes talking about a technical aspect of photography or image processing. I kicked off the series with a demonstration of a workflow (using Bridge and Photoshop) that I used to process one of my images from Bermagui.
I chose this image because it has some short-comings and I wanted to demonstrate how I could overcome some of these with processing. Obviously it is not possible, nor desirable, to “fix” bad images with processing, but I wanted to illustrate a couple of points. I find the image inherently amusing but the background is a bit distracting as it has a lot of color, structure and light areas. Also, there is a pelican in the foreground that could be seen as a distraction, so I am going to demonstrate how to “clone it out.” I want to draw attention to the main subject – namely the fish in the pelican’s beak.
Below is the original raw file that has been opened in Bridge. I have made some adjustments to the exposure and reduced the contrast. In Bridge I almost always go into the Lens Corrections tab (6th from left) and enable lens profile corrections (in the profile sub-tab) and tick remove chromatic aberration (in the color sub-tab). Most of the other adjustments (such as noise removal) I leave on the default values.
Once I am happy with the raw processing in Bridge I click on the “Open Image” button at the bottom and this opens the image in Photoshop.
Above you can see what the base layer looks like without all the adjustment layers (only the bottom layer has an eye symbol to its left). To illustrate my workflow I am going to step through turning on each layer so you can see the effect that it has on the image.
The first layer (above) corrects the color balance. I used the color picker tool (a pencil with a plus sign) and select an area that should be white or neutral grey. I then use a curves layer and adjust each of the colors so that the values for red, green and blue are the same. If they are 255,255,255 then I have adjusted the spot (and the highlights) to white – if the value is less then the spot is grey and I have adjusted the high mid-tones. You can see that this adjustment has removed a magenta cast from the image.
In this layer (above) I have removed the pelican on the left. I used the lasso tool to draw a rough outline around it and then went to the Edit tab at the top of the page and select Fill then Content-Aware to give a rough fill. I then used the clone tool to tidy up the fill, making sure that there are no repeated structures evident. I also built up the tip of the remaining pelican’s wing.
I then have several curves layers where I have progressively darkened the background and lightened the birds. I do this in steps so it gives a more subtle result and I use a different mask for each layer. I use a soft brush to make my masks and usually feather each mask also.
You can see here (above) the mask that I used to darken the background while not changing the birds. You can visualise the mask by going to the channels tab and clicking on the bottom channel, which is usually the mask. Don’t forget to turn the mask channel off before returning to the layers menu (unless you want to see the mask to make fine adjustments to it).
In this layer (above) I am working to give more emphasis to the pelican beaks. I start by changing the color balance and shifting it slightly to the magenta and red (from cyan and green respectively). The rest of the image is masked out so the changes only apply to the beaks. I then apply a hue-saturation layer where I gently increase the saturation in the reds and magentas. I almost always make saturation adjustments selectively and usually avoid increasing the global saturation. I have a second saturation adjustment layer where I have reduced the saturation in the blue and cyan. This often corrects a consequence of darkening (particularly for skies) as Photoshop has the unfortunate tendency to make darkened skies too saturated. Here I am removing color from the water to bring emphasis back to the pelican beaks. Often removing saturation in some colors is a more effective way of emphasising the remaining colors than just increasing those colors’ saturation.
In the next few layers I have lightened the black feathers in the wings to bring some structure back there. I also have a few more layers to reduce the contrast in the water even further. I now want to add more contrast and emphasis to the plumage of the birds. Here I am using a technique for adding structure called HiRaLoam. This is basically a sharpening tool, so I need to work on committed pixels. Most of my layers so far (except for the cloning layer) have been adjustment layers that are basically a set of instructions that tell photoshop what to do with the information from the layers below. A useful shortcut that I use when I need a committed layer (a requirement for sharpening) is to hold down the Control-Shift-Alt-E keys simultaneously. You will see a lot of other ways of doing this, but I have found this to be the quickest and simplest.
To perform the HiRaLoam adjustment I go to the Filter tab at the top of the page, select Sharpen, then Unsharp Mask. Then I use a high radius and a low amount (Amount 30, radius 30, threshold 2). There is nothing magical about these numbers and it sometimes takes a bit of trial and error to get the desired effect. Be sparing with this as it can produce halos (as can all sharpening techniques). I usually start with a black mask, and only add the effect sparingly where I want it, taking care to avoid any obvious edges.
Finally I have a couple more curves layers to get the overall brightness and contrast correct – sometimes it is useful just to use the Auto setting on the curves layer to see where photoshop thinks you should be. You can accept or reject or modify this at your discretion.
Obviously you want to be saving your photoshop file frequently as you go along. If you need to produce a small jpg version of your file my last step is to resize the image. Because photoshop doesn’t retain the detail in the masks at high resolution when it resizes, it is desirable to flatten your image before resizing. Note that this will compress all your workings and discard any layers that aren’t visible. You need to be very careful NOT to save this version of the photoshop file as you will then lose all your working. To resize the flattened image go to the Image tab at the top of the page and then Image Size. Enter the desired values and then save your file AS A JPG. When closing the file photoshop will ask if you want to save it – now say NO to avoid ending up with a low resolution, layerless .psd file. Below if the final version of the image (top). It isn’t markedly different from the original (below) as I like to keep a fairly light touch with photoshop work, but I leave you to judge if it is an improvement.