Lessons 16–17 · 2 lessons · N. I. Taylaqov (general editor), A. B. Akhmedov, M. D. Pardayeva, A. A. Abdug‘aniyev, U. M. Mirsanov. Informatics and Information Technologies, Grade 11, 1st edition. “Extremum-press”, Tashkent, 2018
17
Control work
Textbook: p. 64
GoalChecks what has been learnt about lessons 10–16 (layers, colours, channels and filters, brush and pencil, shapes, text) in control tasks.
New words
layer: a transparent sheet of a picture; layers stack · qatlamcolour systems for screens / printing / designers · RGB / CMYK / HSBchannel: one colour component; filter: processing by an algorithm · kanal va filtrthe three results of a shape tool: a vector shape, an outline, or plain pixels · Shape / Path / Pixels
Explanation
This control work covers the second half of Chapter I. The theory questions are about layers, colour systems (RGB, CMYK, HSB, Lab), channels and filters, the difference between Brush and Pencil, and working with text. The practical task is usually a small composition of several layers: a background, a cut-out object, a shape and text; you save the work as PSD and also export a JPEG copy. The calculations include the opacity formula (upper·Opacity + lower·(1 – Opacity)), the size of a 24-bit picture, a hexadecimal colour code and converting points to pixels. To prepare, repeat the key of each tool (B, U, P, T, I) and the buttons of the Layers palette, write a table of where each colour system is used, and remember how to undo mistakes (Ctrl+Z, the History palette).
Worked examples
A sample calculation: the channel is 220 in the upper layer and 60 in the lower, Opacity = 75%. Result: 0.75·220 + 0.25·60 = 165 + 15 = 180. The hexadecimal code of RGB (0, 128, 255) is #0080FF; a 600×400 RGB (24-bit) picture is 600·400·3 = 720 000 bytes.
A sample practical task: create a new 1200×800 pixel file; give the background a gradient (or one colour); place a cut-out picture on a new layer and copy it at 60% opacity as a shadow; add an ellipse shape and 36 pt text; save “work.psd” and “work.jpg”.
Class activity
“Question bank”: each group writes 6 questions (2 theory, 2 calculation, 2 practical) from lessons 10–16 of Chapter I and prepares an answer key; groups swap and solve them.
Practice
1
The channel is 220 in the upper layer and 60 in the lower, Opacity = 75%. What is the result?
180
2
What is the hexadecimal code of RGB (0, 128, 255)?
#0080FF
3
Match colour systems to their roles: screen, print, a designer-friendly angle-based system.