2 Digital Images Free Online FlashCards

How does a digital camera capture an image?

A lens focuses light onto an electronic sensor, which samples it at many locations; each sample contributes to a pixel.

What is a raster image?

A raster image is a rectangular grid of pixels, with each pixel storing a color value.

What do pixel dimensions describe?

Pixel dimensions are an image’s width and height measured in pixels; they indicate how much image detail is stored.

What does the RGB color model store for each pixel?

RGB stores a red, green, and blue value for each pixel.

How many values can an 8-bit color channel store?

Each channel can store 256 possible values.

What does PPI describe, and does changing it add detail?

PPI describes pixel density at a printed size; changing it alone does not add image detail.

About what size does a $3{,}000 \times 2{,}000$-pixel image print at 300 PPI?

It prints at about $10 \times 6.7$ inches.

What does resampling do to an image?

Resampling adds or removes pixels and can affect image quality.

What does lossless compression preserve?

Lossless compression reduces file size without discarding image data.

How does JPEG typically reduce image file size?

JPEG typically uses lossy compression to reduce file size; stronger compression can make visible artifacts more likely.

How can you protect an image’s original pixels while editing?

Keep an untouched original and edit a separate working copy; layers or adjustment layers make changes easier to revise.

How many pixels are in an image measuring $3{,}000 \times 2{,}000$ pixels?

It contains 6 million pixels.