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Lossless Compression explained simply

What is “Lossless Compression”?

Reducing file size in a way that lets the original stored data be recovered exactly.

  1. 01Original data
  2. 02Compact storage
  3. 03Same recovered data
Visual reminder: Original data → Compact storage → Same recovered data. The illustration is a learning aid; use the practical exercise below to see the effect in a real photograph.

How do you use Lossless Compression practically?

A small exercise

Save a suitable image with a supported lossless option and reopen it. Compare the image data and file size within your workflow.

  1. Make a starting version and keep it so you can compare fairly.
  2. Try the change in the exercise. Keep unrelated choices steady where the exercise allows.
  3. Compare the result at the size your viewer will actually see. Write down what changed and whether it helped.

How does Lossless Compression solve a problem?

It saves storage without discarding the information the chosen format holds.

What can go wrong?

Lossless does not mean every earlier step was lossless. Converting a JPEG to PNG does not restore lost detail.

How do you turn the idea into a useful solution?

Start with the specific problem in your image or brief, try the exercise, and keep the version that meets that need. If the result is worse, return to the starting version and change one choice at a time.

Quick check: can you explain the three ideas in the diagram?

Original data → Compact storage → Same recovered data. Explain how each relates to the exercise. Then compare the starting version with your result and choose the one that meets your brief.

Related video lesson

File formats — Canon

This related lesson gives wider context for the topic. Camera menus and software versions may differ from yours.

Loading the player connects to YouTube. You can also watch the lesson on YouTube.

Keep exploring

Try the idea in a studio shoot

Planning a portrait or product session? Use the glossary with our practical shoot guides, then check the studio facilities and send your confirmed requirements with an availability enquiry.