The toolbar is the funky thing that looks like this:
The top tool (the one that looks like a magnifying glass) is the Zooming tool. The bottom tool is called the Rectangle Selection tool, but we'll learn more about that in a little bit.
Click on the Zooming tool to select it. Bring the mouse over the digital image (the picture). Zoom in a spot in the picture by clicking with the left mouse button.
Each time you click with the left mouse button on the picture, the Zooming tool will magnify the image. You'll eventually start to see the pixels as individual squares, each having their own color.
Continue to Zoom in to the picture. Something should eventually happen.
What happened when you zoomed in?
What eventually happens when you zoom in is that the Pixel Calculator shows the pixel numbers or Gray Values. This is how the computer actually stores the color of the pixels in the image.
Unfortunately the computer can't store all of the different shades of gray (that would take too many number!) Instead it does as best as it can with values from 0 to 255.
Look around the zoomed in image and answer these questions. (You have to see the numbers for these questions)
What is one of the smallest gray values you see on the screen?
What is the color of that pixel? Black Dark Gray Medium Gray Light Gray White
What is one of the largest gray values you see on the screen?
What color do you think a pixel with a gray value of 0 would be? Black Dark Gray Medium Gray Light Gray White
What color do you think a pixel with a gray value of 255 would be? Black Dark Gray Medium Gray Light Gray White
(Factoids are little facts that you can impress your friends with)
How does can a picture get inside the computer anyway? Typically a pictures are brought into the computer using special devices called digital cameras or digital scanner.
A digital camera looks a lot like a fancy camera you might even own, but instead of taking picture on film, it translates the picture into something the computer can understand.
A digital scanner looks a lot like a photocopying machine, but instead of putting the copy on another piece of paper, it puts the copy into a format that the computer can understand.
Well since we showed you how to Zoom in to see the pixel values, we thought we'd show you how to Zoom out again.
Click on the Zooming tool to make sure its selected. Bring the mouse over the digital image (the picture). Zoom out from a spot in the picture by clicking with the right mouse button.
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