Exam practice

• i.Brightness multiplies all three numbers (red, green, blue) by the same amount: more than 1 to lighten, less than 1 to darken.
• ii.Contrast pushes the numbers away from the middle, 128: numbers above it go up and numbers below it go down, so light gets lighter and dark darker. Less contrast pulls them towards 128, towards gray.
• iii.Saturation pushes a pixel’s three numbers apart from each other (away from the gray they average to), so colors get stronger; at zero, the three numbers become equal and the pixel is gray.
• iv.Warmth (white balance) raises red and lowers blue, to warm a photo that came out too blue, or the other way round to cool one that came out too orange.

Clipping happens when an edit (or the camera, with too much light) pushes pixels’ numbers past 255 or below 0. The numbers stop at 255 or 0, so pixels that were slightly different all become the same, flat white or flat black, and the detail between them is lost.
It can’t be undone because the edited photo no longer holds the differences: making it darker turns all those pixels the same gray, not back into their old values.
To avoid it: don’t push the sliders too far, watch the histogram for a spike at either end, take photos with less bright sky in them or tap to focus on bright parts, and keep the original so you can start again.

The size in pixels (resolution) is how many pixels it has across and down; it sets how much detail it can show. The file size is how many bytes the saved file takes; it sets how long it takes to send and how much space it uses. They are linked (more pixels usually means a bigger file), but compression and quality also change the file size.
In the form, 600 × 600 pixels is the size in pixels, and under 200 KB is the file size.

• i.3,000 × 2,000 = 6,000,000 pixels × 3 = 18,000,000 bytes. 18,000,000 ÷ 1,024 ÷ 1,024 ≈ 17.2 MB.
• ii.The width is divided by 3,000 ÷ 750 = 4, so the height is 2,000 ÷ 4 = 500 pixels. Pixels: 750 × 500 = 375,000, which is 375,000 ÷ 6,000,000 = 1/16 of them (a quarter across times a quarter down).
• iii.375,000 × 3 = 1,125,000 bytes ÷ 1,024 ≈ 1,099 KB (about 1.1 MB). Saved as a JPEG it would be much smaller still.

1. Read exactly what the form asks for: format, size in pixels, file size, background.
2. Keep the original, and work on a copy.
3. Crop it to the shape asked for, cutting away what isn’t needed.
4. Resize it: to the pixels asked for, or about 1,000 to 1,600 pixels across if none are given. This removes most of the bytes.
5. Save it as a JPEG at about quality 80, and check the file size.
6. If it is still over 200 KB, lower the quality a little at a time, checking each time.
7. Zoom in and look: the face or the writing must still be clear, with no blocks or smudges.

Lossless compression stores the file in fewer bytes without losing anything: uncompressed, it is exactly the original. Example: PNG, best for screenshots, diagrams and pictures with text or sharp edges.
Lossy compression throws away detail that people hardly notice, so its files are much smaller, but the lost detail can never be got back. Examples: JPEG for photos, MP3 for sound, MP4 for video.

• i.JPEG: made for photos, small, and accepted by almost every form.
• ii.PDF: keeps the page exactly as it was laid out and prints the same on any computer.
• iii.MP3 (or M4A): sound only, small, plays on every phone.
• iv.PNG: lossless, so the small text in the screenshot stays sharp.

Any five, for example:

1. Record in a quiet room: noise from a fan or a road makes the voice hard to hear.
2. Choose a room with soft things (curtains, bedding): they soak up echo; bare walls bounce it back.
3. Hold the phone 15–20 cm from the speaker’s mouth: the voice is strong at the microphone, much stronger than the room’s noise, which stays the same wherever the phone is.
4. Keep the phone a little to the side of the mouth: the puffs of air from “p” and “b” go past, not into the microphone as thumps.
5. Keep the phone still on a cloth, and don’t cover the microphone: handling noise is loud to it.
6. Turn on Do Not Disturb or airplane mode: a call or a message sound would spoil the recording.
7. Test first, listening with earphones, which show up hum and echo.
8. Record a few seconds of silence, for noise reduction later.

1. People who are deaf or hard of hearing can follow it.
2. Many people watch with the sound off: in a bus, in a class, at night.
3. People who understand written words better than speech (in Nepali or English) can follow, and can read a word they didn’t catch.

(Also: the speaker’s words can be found by searching, and captions help when the sound is poor.)

• i.Too little contrast: white letters vanish against the bright sky. Put a dark band or a dark shadow behind them, or move them to a darker, calmer part of the photo.
• ii.Too small to read on a phone, and in the corner, where the screen’s rounded corners and the app’s buttons cover it. Make it big and keep it away from the edges.
• iii.It is dishonest: it promises something the video doesn’t have. Viewers who feel tricked stop trusting the channel. Use an honest title and a clear photo from the event.

CC BY (CC BY 4.0): anyone may use it for anything, as long as they credit you. (CC BY-SA would also be accepted by Wikipedia, if you want changed versions shared the same way.)
Not CC BY-NC, because Wikipedia and Wikimedia Commons accept only work that may also be used to make money; an NC photo can’t go there, and many other good uses would be ruled out.
Under the photo: “© . Shared under CC BY 4.0.”

Any four, for example:

1. Fairness to the maker: being named is how photographers and musicians get known and find work. Example: a Nepali singer’s song reposted without credit sends the listeners and the money from views to someone else.
2. Honesty: credit shows which parts you made. Example: a project that uses a classmate’s drawing without their name passes it off as yours, which is plagiarism.
3. Checking: credit lets others find and check the original. Example: a viewer can follow a photo’s credit to see where and when it was really taken.
4. It keeps sharing going: people share under Creative Commons because others keep its condition of credit. Example: if photographers on Wikimedia Commons saw their photos used without names, fewer would share.
5. The law: copyright laws, such as Nepal’s Copyright Act, 2059 (2002), protect creators and their right to be named. Example: using code without keeping its license notice breaks the license, so the use is no longer allowed.