Images Flashcards
How are graphics displayed on a screen?
They are displayed with pixels (picture elements)
How do you make an image look better or higher resolution?
Using a higher number of pixels per inch (ppi) will increase the resolution of the image and make it look clearer.
What are the drawbacks of using more pixels?
The file sizes of the images will increase dramatically and fewer images will be able to be stored.
What are the two different types of images?
Bitmaps and Vectors
What are bitmaps?
Bitmaps are organised as a grid of coloured squares called pixels.
What happens when zooming in on a bitmap?
When zooming in the pixels are stretched and made into larger blocks. This is why bitmap images look worse when enlarged too much.
How are different colours represented on bitmap images?
They are represented with a binary number.
What is colour depth?
Colour depth is the number of bits an image is measured in. Number of bits = the number of colours that can be displayed.
How many bits are needed for black and white images?
1 bit is needed for black and white images. A colour depth of 1.
How many bits are needed for four colours in an image?
2 bits are needed (colour depth of 2).
How do you work out the number of colours available in each colour depth?
Do 2 to the power of the colour depth to get the number of colours available.
What is the colour depth of most images on the internet?
24 bit (16 million colours)
How to work out the filesize of an image?
Width x height x depth = filesize/volume in bits
