Adobe Photoshop
 As
a professional, the power and flexibility offered by the latest versions
of Adobe Photoshop (I use Photoshop CS) make a difference in the work
I do. For most non-professionals, why pay $800 to edit an image from a
$200 digicam?
Adobe also offers Photoshop Elements.
Photoshop Elements is essentially the main elements that make up Photoshop - some
of the most commonly used features are included without the high price
tag. It is carried by most retail stores for around $50, and some digicams,
printers, and scanners even come bundled with a free copy of Photoshop Elements.
In fact, my copy of Photoshop Elements came with my ColorVision
Spyder monitor calibrator.
In this section, have used screen captures from
Photoshop 7.0 for simplicity's sake.
Step 1: Open
  We fire up the application and bring in the image
we saved from our RAW editor. Nikon Capture supports a direct transfer
to Photoshop without having to do the intermediary save. But, I do the save
so it gives me a backup copy. If I mess the image with Photoshop,
I do not need to recreate all of the work done in my RAW editor. |
Step 2: Levels
  I now open up levels: Image -> Adjustments -> Levels… At
this stage we want to make sure the histogram still looks okay, and we
want to check to see how our work has changed the histogram
characteristics.
We can fine tune levels at this point by dragging
the little triangles below the histogram. Holding the [Alt] key ([Cmd]
key on the Macintosh) while adjusting the upper and lower limits allows us
to see which areas we are clipping. |
Step 3: Horizon
   The
first thing is the photo appears to be slightly off angle - the tang seems
tilted. In order to correct this we right-click on the eyedropper
tool (hold it down on the Mac). A fly-out menu will appear and allow
us to select the measuring tool.
We then use this measuring tool to draw either a
horizontal or vertical axis on which to base the new horizon on. Here
I used it to draw a line through the long axis of the fish.
Selecting Image -> Rotate Canvas -> Arbitrary… brings up a dialog
box telling us the line we drew was 4.16º CCW from the horizontal. We
select OK and the canvas is rotated so the line is now horizontal. The fish no longer appears to be leaning to the side. |
Step 4: Crop
 We now want
to subtract out information we are not interested
in and does not contribute to the image. Select the crop tool
to do this. We leave the Width and Height blank, so the tool does not resize the image, it just chops off the
uninteresting parts as if we were working with scissors and a piece of
paper. |
Step 5: Healing Tool
  Okay,
now we get to work! We need to clean up the marine snow to get a nice clean image.
Select the healing brush, and zoom-in on
the image. Then select a brush size that is large enough to encompass the spot
and go over each spot, one-by-one. At the same time, we can clean up
scratches and minor bugs in the glass surface.
There are countless other was to address this issue,
however none of these techniques work quite as well. Think a fine hand-made Swiss watch vs. a mass produced Chinese watch.
Some other techniques:
- Dust and Despeckle: Using a radius large enough
to get the spots wipes out so much detail the end result looks like
a water painting.
- Resizing and then using Healing Brush: Yes
we will
have fewer spots because smaller spots are averaged in with neighboring
pixels. But this averaging decreases contrast and causes the
image to look washed out. It is similar
to mixing a few sprinkles of white paint in with black paint. Swirl
it around, and the white paint disappears, as it is averaged (mixed)
in with the black. But black no longer appears black, it is a bit grayish. Additionally the remaining spots become closer together and more difficult
to remove accurately with a broad brush stroke.
- Using the Blur Tool: This is the worst method. It simply takes the white specks and smears them all over the place. Not only does the detail get wiped out,
and not only is the noise averaged
in, reducing contrast, but it also changes the noise characteristics
of the image. The smooth areas resulting from the blur tool will stand
out from the slightly grainy areas where the blur tool was not applied.
This inconsistency creates a fake quality to the photograph were we
can tell something is a bit off.
|
Step 6: Clone Tool
 Now that we have a nice clean image, we can look
at the photo overall and remove some distracting elements. Here, we will
remove the Chromis viridis' tail growing out of Dory's head.
We work the tool much the same way as the healing
brush, frequently taking new sampling points so as not to create a repeating
pattern. |
Step 7: Resize
  After we are satisfied with the image, we want
to resize it for its destination. Now would be a good time to make a backup
copy in case we want the full sized image to output to a different destination. For web, we want to keep sizes down, and keeping
in mind that very few people have screens that are 3000+ pixels across,
we choose a more manageable size of 800 pixels or less in the longest
dimension. |
Step 8: Sharpen
  Notice all this time we have been working with
sharpening set to off. After resizing, we now want to apply our sharpening
so our photograph gets that extra punch and edges look crisp. Had
we sharpened prior to resizing, the resizing process would average all
those pixels and soften the image up. Sharpening, averaging, and sharpening
again causes the accumulation of artifacts and as a result we end up
with an over-sharpened looking image that lacks detail.
In the dialogue box to the right, we chose a large amount of
sharpening and see a halo around edges - this is indicative of an over
sharpened image. Click on the image to see
a side-by-side comparison for of an over sharpened and a properly
sharpened image. To sharpen, we want to bring the
level up to where we can see the halo, and back down a bit until it just
disappears as with the right image. For printed output sources over-sharpen slightly.
Radius - is the number of pixels the algorithm uses
for edge contrast enhancement.
Threshold - affects the noise characteristics of the image.
Increase this
value if the image is noisy. |
Step 9: Convert to sRGB
  We
have been working this entire time in aRGB. Since we want to output to
web, we need to convert the profile to sRGB so colors are displayed
properly in web browsers. Select Image -> Mode -> Convert to Profile… and select sRGB in Destination Space. |
Step 10: Mode
 Remember JPEGs are 8bpp images and
we have been working with a
16bpp image. As such, we need to change to 8bpp before we can save a JPEG.
Select Image -> Mode -> 8 Bits/channel. |
Step 11: Save
   Save as JPEG. For the web to keep the file size small, we want to
select around Quality 10, or about 80% compression. I would not recommend
going below level 60% compression (or Quality 8) as artifacts start significantly
degrading the overall image quality we just spent all this time trying to
fine tune. |
End Result:
This photograph could have been much better if we
took the time to shoot it properly to begin with. By getting the
most out of the actual photo session, we maximize the quality of image
captured by the camera, thereby not only saving time and effort, but
getting cleaner, sharper, and more brilliant images as a result.
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