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IT & Tech Intermediate

Colour Contrast & Accessibility Math: WCAG Contrast Ratios & Relative Luminance

Hex to RGB, sRGB linearisation, relative luminance, contrast ratios, AA/AAA for normal and large text, darkening a failing brand colour, a full palette contrast matrix with highlighting and a contrast report with a chart: 8 graded labs on one fictional design studio.

8 lessons 8 labs 1.9 h Certificate

  • One-time payment
  • 14-day money-back guarantee
  • Secure checkout with Stripe

What you'll build

What you will be able to do

Each lab ends with a concrete result that you build yourself and the checker confirms, cell by cell.

  • Split Fernhill Studio's brand colours from hex codes into red, green and blue values, and build hex codes from RGB values.
  • Turn 8-bit channel values into the linear light values that WCAG's luminance formula needs.
  • Calculate the relative luminance of Fernhill's eight palette colours and choose black or white text for each.
  • Calculate WCAG contrast ratios for eight text/background pairs, label them as "x.xx:1" and find the darkest background white text can use.
  • Decide which of eight website elements count as large text and whether each passes WCAG level AA and AAA.
  • Fernhill's Apricot fails on white. You darken it in 5% steps, recalculate luminance and contrast, and find the smallest change that passes AA.
  • Build the full 6 × 6 contrast matrix of Fernhill's palette with one formula, count the usable pairs and highlight every pair that passes AA.
  • Turn Fernhill's audit of eight UI elements into a report: target, status, shortfall, pass rate and a chart that shows which ratios miss the bar.

About this course

Contrast checkers give a verdict, but this course shows you how that verdict is calculated, so you can fix a palette instead of guessing. You convert hex colours to RGB and back, then linearise sRGB values with the piecewise gamma formula. From linear values you compute relative luminance and the contrast ratio between two colours. Pass and fail rules for AA and AAA are applied to normal and large text. You darken a failing colour step by step until it passes, build a contrast matrix for a full brand palette with highlighting and finish with a report showing pass rate and shortfalls. For UI designers, front-end developers and accessibility specialists.

Curriculum

Course content

8 lessons · 8 labs · 1.9 h · final exam

  1. Hex Colours to RGB and Back: HEX2DEC, MID & DEC2HEXLab12 min3 checked tasks
    Unlocked when you buy the course
  2. sRGB to Linear Light: the Piecewise IF with ^2.4Lab13 min4 checked tasks
    Unlocked when you buy the course
  3. Relative Luminance: 0.2126 R + 0.7152 G + 0.0722 BLab15 min3 checked tasks
    Unlocked when you buy the course
  4. Contrast Ratio: (L1 + 0.05) / (L2 + 0.05)Lab13 min3 checked tasks
    Unlocked when you buy the course
  5. AA & AAA: Pass/Fail for Normal and Large TextLab15 min4 checked tasks
    Unlocked when you buy the course
  6. Fixing a Palette: Darken Step by Step Until It PassesLab16 min4 checked tasks
    Unlocked when you buy the course
  7. Contrast Matrix for a Brand Palette: Mixed References & HighlightingLab16 min4 checked tasks
    Unlocked when you buy the course
  8. Contrast Report: Pass Rate, Shortfalls & a Chart of Ratios vs TargetsLab15 min4 checked tasks
    Unlocked when you buy the course
  9. Final exam12 questions, 75% to pass, unlimited retries.

Certificate

Finish with a certificate you can verify

Complete every lesson and pass the final exam to receive a certificate of completion for this course, with a unique credential ID and a public verification page.

  • Names the course, your score and the date of issue
  • A verification link for your CV or LinkedIn profile
  • 12 questions, 75% to pass, unlimited retries.

A Tutorvo certificate confirms that you completed a course. It is not an official or professional qualification.

Illustration. Your certificate shows your own name, course and credential ID.

Before you buy

Questions about this course

Is this a subscription?

No. You pay $9.99 once for this course. There is no subscription and nothing renews automatically. Prices are in US dollars; taxes may be added where required.

What exactly do I get?

All lessons and labs of this course, the final exam and the certificate, including later updates to the course, for as long as Tutorvo offers it. Access is personal and tied to your account.

Can I get a refund?

Yes. If you are not satisfied, email hello@tutorvo.com within 14 days of buying and we refund the course in full via Stripe. The guarantee does not apply once a certificate for the course has been issued to you, or where there are signs of abuse.

When can I start?

Right after payment. Access starts immediately at your request; for consumers in the EU/EEA the statutory right of withdrawal therefore ends once access has begun, while our 14-day money-back guarantee applies regardless.

Do I need Excel or other software?

No. The labs run in a spreadsheet inside your browser on a laptop, tablet or phone. Function names and syntax follow Excel.

Is the certificate an official qualification?

No. It confirms that you completed all lessons of the course and passed its final exam. It is not an official, state-recognised or professional qualification. The name is taken from your profile when the certificate is issued.

Full details are in our Terms · hello@tutorvo.com

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