Over the centuries, our view of light has changed dramatically.
The first real theories about light came from the ancient Greeks. Many of these
theories sought to describe light as a ray -- a straight line
moving from one point to another. Pythagoras, best known for the theorem of the
right-angled triangle, proposed that vision resulted from light rays emerging
from a person's eye and striking an object Light is part of the
electromagnetic spectrum, which ranges from radio waves to gamma rays.
Electromagnetic radiation waves, as their names suggest are fluctuations of
electric and magnetic fields, which can transport energy from one location to
another. Visible light is not inherently different from the other parts of the
electromagnetic spectrum with the exception that the human eye can detect
visible waves. Electromagnetic radiation can also be described in terms of a
stream of photons which are mass less particles each travelling with wavelike
properties at the speed of light. A photon is the smallest quantity (quantum)
of energy which can be transported and it was the realization that light
travelled in discrete quanta that was the origins of Quantum Theory. It’s a
kind of energy called “electromagnetic (EM) radiation” (but this kind of
radiation is not harmful, except for occasional sunburn). There are other kinds
of EM radiation too (radio waves, microwaves, x-rays, etc.), but light is the
part we can see, the part makes the rainbow.
Saturday 28 June 2014
Friday 13 June 2014
Selection Tools in Photoshop
Lasso Tool
The Lasso Tool is 100% freeform. Simply grab it and start drawing with your mouse or track pad to make a selection. Obviously, the result is going to be rudimentary at best and even tends to be quite sloppy.
The Lasso Tool is 100% freeform. Simply grab it and start drawing with your mouse or track pad to make a selection. Obviously, the result is going to be rudimentary at best and even tends to be quite sloppy.
Polygonal Lasso Tool
The Polygonal Lasso Tool allows you to click from point to point to gradually build a selection. Selections made with this tool are purely comprised of straight edges. If you don’t mind some tedious clicking, you can pull off a primitive curve, but for the most part you’ll definitely want to stick to hard edges.
The Polygonal Lasso Tool allows you to click from point to point to gradually build a selection. Selections made with this tool are purely comprised of straight edges. If you don’t mind some tedious clicking, you can pull off a primitive curve, but for the most part you’ll definitely want to stick to hard edges.
Magnetic Lasso Tool
The Magnetic Lasso Tool is a lot like a cross between the Polygonal Lasso Tool and the Magic Wand Tool. It allows you to build your selection incrementally, but in a fairly automatic fashion. Simply move your mouse along an edge and the MLT will give its best guess for outlining that edge. You can let the tool build your points automatically or manually click if there’s a specific point that you think needs to be dropped.
The Magnetic Lasso Tool is a lot like a cross between the Polygonal Lasso Tool and the Magic Wand Tool. It allows you to build your selection incrementally, but in a fairly automatic fashion. Simply move your mouse along an edge and the MLT will give its best guess for outlining that edge. You can let the tool build your points automatically or manually click if there’s a specific point that you think needs to be dropped.
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