Week 8: Lab (manipulating images using arithmetic)

Today's lecture was on light and images. The task for the lab is to open an image in Photoshop CS4 and manipulate it using filters and arithmetic. 

First I opened the file 'ch_tor.jpg' in Photoshop and rotated it so that it was the right way up. I then applied a custom filter to it.

As you can see, the custom filter made the image much sharper and very grainy. 

The high pass filter made the image look quite monotone, with a glow. I thought it was quite a nice effect.

The maximum present filter mask made the image look brighter while the minimum filter made the image look darker. They both made the image look slightly blurred. 

I experimented with several other filters to see the effects. Two of the filters that I tried were the Stylised: Find Edges filter and the Pixelate: Colour Halftone filter. 

Find Edges:

Colour Halftone:

I then created a new filter that was all zeros except for the centre value, which I made 1. After applying this filter I did not see any difference to the image.

Next I created a filter with a two by two matrix of 1s at its centre. This filter made the image significantly whiter.

Lastly I created another filter with a two by two matrix of 1s on one diagonal and -1s on the other. This made the image almost entirely black with only a very faintly visible outline.