Introduction to Graphics

Lesson objectives

By the end of the week, learners should be able to:

1. Identify at least five bitmap graphics formats and tell which is common on phones.
2. Explain the difference between raster and vector graphics.
3. Name three drawing tasks a graphics package can perform.
4. Create a symmetric artwork using a graphics package template.
5. Export a saved image into another format for reuse.

Key vocabulary

• Bitmap: a grid of coloured pixels arranged to form an image.
• Pixel: one tiny square of colour in a bitmap.
• Raster: another name for bitmap graphics.
• Vector: shapes defined by mathematical equations rather than pixels.
• Resolution: the number of pixels in an image.
• Symmetry: mirroring half of an artwork to make a balanced whole.
• Format: the file extension describing how an image is stored.

Common misconceptions

• "Photographs are always best for a logo." Vector logos scale without losing clarity, making them better for brand marks.
• "Higher resolution always looks better." Higher resolution increases file size and slows editing for small screens.
• "Vector cannot include photos." Vector artists use photographs as reference layers beneath vector shapes.

Teacher activities

1. Starter: display two identical logos, one bitmap and one vector; ask which looks sharper when enlarged.
2. Define raster and vector and compare them with one concrete example each.
3. Present five bitmap formats and rank them by common phone use, showing examples from device cameras.
4. Model symmetric artwork creation on a template and enlarge the canvas a few times.
5. Demonstrate exporting an image to a different format and choosing quality settings.
6. Run the creation task and close with each learner naming one format on their phone camera.

Student activities

1. Choose the sharper logo from the starter display and explain why.
2. Copy the raster versus vector definitions and give one advantage and disadvantage each.
3. Rank five bitmap formats and explain which is common on mobile phones.
4. Create symmetric artwork on the graphics template and compare it at two scales.
5. Export the saved image to a different format and check the file size change.
6. Answer the exit question comparing raster scaling behaviour.

Practical / learning evidence

A symmetric artwork saved in two formats, the original and a copied format, plus a one-page comparison table of raster versus vector showing advantages, disadvantages and uses. Both images must open independently.

Resources and preparation

Computers with a graphics package, a symmetric template image, sample format files and a phone photograph set. Offline route: paper symmetry drawing and format comparison table, no device needed. Keep cameras out of the laboratory unless supervised.

Assessment for learning

Inspect the two saved images and verify the format change altered size and clarity appropriately. Ask two learners to explain the tradeoff between higher resolution and smaller screen viewing. Mark the comparison table for equal treatment of both sides.

Inclusion and homework

Provide the symmetric template preprinted so learners focus on colours rather than layout. Allow a learner with low vision to increase canvas size before creating the artwork. Extend confident learners by asking how vector art handles resolution changes without losing clarity. Homework: take five phone photos in one colour group and save them in one bitmap format to observe file size differences.