Image Processing Techniques

1. Photography and Digital
Manipulation
Chris Bailey
1
Image Processing and Techniques

2. Pixelation

3. What could cause this to occur?
When an image is cropped down or are shot in a low resolution the
pixels that make up the image can begin to appear and make the
image look low quality. Low resolution sensors are on a lot of mobile
phones and older digital cameras, although most are capable now of
creating now visual pixilation in the main image (before cropping).
What preventable measures are there?
If images are shot in a higher resolution the image will show less
pixilation than one shot in low resolution. If the editor crops the
image less there will be less pixilation than if it is cropped a lot. The
photographer can also use a telephoto lens to get closer to the
subject rather than cropping into the image in post or using digital
zoom on a camera.
Finally, how could you fix it?
The pixelated image can be smoothened down in Photoshop using the
bicubic smoother to make the image look less harsh with its bold
pixels. This can be achieved by image > image size > bottom drop
down menu.

4. Colour Casts

5. What could cause this to occur?
Sometimes the photographer will set the cameras white balance to
automatic, which allows the photographer to leave the white balance
options for the camera to decide. But sometimes the camera can be wrong,
certain colours hit a blind spot in the cameras algorithm for detecting white
balances, which cause it to choose the wrong one and give an image a
strange unrealistic tone.
What preventable measures are there?
The photographer can take test shots with different white balances in order
to see which one makes the image look the most realistic. Or they can shoot
in RAW files which store no specific white balance options and don’t
compress the image meaning they can edit the image in post.
Finally, how could you fix it?
It can be fixed in post production by counter acting the image tones, such as
a warm orange tone can be counter acted with a cooler blue tone. Or vice
versa.

6. Picture Damage 1

7. Damaged Image 2

8. What could cause this to occur?
An image being left for a long period of time with an object on top of it or in
a creased position could end up losing some of the print from the image
making it look badly damaged. Image damage overall, not just physical
image damage, can be be due to many causes. For example sensor damage,
memory loss, broken elements and glass on lens, file corruption and
irreparable edits that ruin an image.
What preventable measures are there?
Keep images flat in a hardback album in order to keep the images protected.
This will prevent them from being creased, water damaged, stained and
ruined. The images can also be backed up on an external hard-drive to
ensure that there is always a second copy of them.
Finally, how could you fix it?
The image can be scanned and put into an editing software such as
Photoshop, and using some preset tools such as the spot healer the editor
can remove the creases and damage in the image. Memory loss can make
some images irreplaceable but some software's search for left over data in
order to retrieve the image again.

9. Over or Underexposed Images

10. What could cause this to occur?
The photographer may have settings chosen that do not let enough
light into the sensor, such as a shutter speed to fast, an aperture too
narrow, or an ISO too low. These all make an image darker which in
some cases have to be corrected in post production.
What preventable measures are there?
Usually a camera will counter act the settings in order to make an
image correctly exposed, such as if the photographer is on shutter
priority with a 1/5000ths the camera will widen the aperture to f/3.5
in order to balance the exposure. The photographer could also set
the ISO to auto in order to balance the settings automatically.
Finally, how could you fix it?
It is very simple to fix exposure problems in Photoshop, by simply
choosing the exposure option and dragging a slider from the middle,
to the left (darken) or the right (brighten). This gives the editor
simple but effective controls over the exposure in post production.

11. Panorama
Pre-Edit
Post-Edit
Edit: Basic levels +
Dodging &
Burning.

12. 12
Planorama

13. 13
Edited
Planorama:
This planorama has had
multiple edits in order to
make it more appealing
to the eye. For example
the lighting and contrast
have been altered in
order to make the image
brighter and to increase
the level of contrast.
There have also been
more technical edits such
as fixing the path and the
alignment of the
benches, also the tree
trunk that was out of
line.

14. Evaluation
How did you create your image?
I took a series of images and compiled them using Photoshop ‘PhotoMerge’
which let Photoshop stitch the images together to make a panorama. After that
I checked for any issues with the image, once it was clear of problems (instantly)
I saved it as a jpeg. The edits were a mix of basic lighting and contrast,
alongside the more technical spot healing, lasso selection, and clone stamp tool.
I used to lighting and contrast to make the image easier on the eye, and the
clone, lasso and spot healer to fix the issues in the image such as misalignment.
What would you improve if you did it again?
I would create an exposure that keeps the whole image decently exposed,
because the hill in the centre of my image is underexposed quite badly which
isn’t very attractive.
After Edit: After editing my image I realised that it would have been better to
take my image using a tripod as a lot of parts of the image were out of line, such
as 2 tree trunks, benches and branches. Which were not easy to edit.

15. Hockney Joiner

16. Evaluation
How did you create your image?
I took 21 photographs of a tree and stacked them using Photoshop
‘Photomerge’ but unlike the panorama, I selected for the images not
to be blended as I wanted to keep the messy stack look. I then
selected each of the 21 images individually and changed the hue,
saturation, contrast and colour balance in order to make them all
different.
What would you improve if you did it again?
If I were to do it again I would start taking photos starting lower
down, including more of the ground in the image as it could have
looked good. I would also take more shots to make the individual
boxes of colour smaller, making the colour differences smaller but
giving it more of a random look.

17. Photo Montage Photomontage:
1
2
3

18. Evaluation
How did you create your image? (Image No.2)
I used the quick selection tool to remove the background sky, and place in
an image of a sky painting. But to keep the brightness similar I placed the
original sky underneath the new one, and increased the opacity of the new
one, allowing the brightness of the original to seep through. I then placed a
ghost busters image in, and deleted its surroundings so that only the main
subject was visible, I then created a new layer and increased its opacity to
create its reflection on the water.
What would you improve if you did it again?
If I did it again I would put more detail onto the reflection of the monster, and
the water within its close vicinity. Such as ripples around the monsters feet or
splashes, so show the movement, rather than it just hovering above the
water.

19. Colourised Image

20. Colourised Image

21. Evaluation
What tools did you use to create your images?
I mainly used the magic wand tool, and the colour range options to
select certain areas and colour them. I also used the quick selection
tool on some parts of my image, this gave me more control over
what was selected. For full control I used the lasso tool, this gave me
complete control over what was selected, although it was not easy to
use. I definitely preferred using the magic wand tool.
How did you utilise file formats?
I used put the normal JPEG files into Photoshop and edited them as I
needed to, but saved a copy as a PSD and a JPEG. I did this so that I
have more control over the edits if I have to change anything using
the PSD rather than using the new JPEG which has been compressed
to a new image already.

22. Evaluation
Was there any ethical issues?
The image of the cars could be potentially an issue when colourised.
This is due to the colour of the real cars being unknown, they might
represent the states or families the drivers are racing for, but I do not
know what colour they are and have had to guess.
What would you improve if you did it again?
I would select the trees in both images with more detail using a new
technique that I learnt after completing it. The trees have been
slightly coloured into the sky which has created a strange outline on
them. This doesn’t effect the image too much although it does look
un-natural.