Cambridge International AS & A Level Cambridge International AS & A Level
COMPUTER SCIENCE 9618/12
Paper 1 Theory Fundamentals May/June 2026
MARK SCHEME
Maximum Mark: 75
*
COMPUTER SCIENCE 9618/12
Paper 1 Theory Fundamentals May/June 2026 Published
1 hour 30 minutes
You must answer on the question paper.
This mark scheme contains the instructions and marking guidance that our examiners used to mark
No additional materials are needed. candidate responses for this component.
*
Before they start marking, examiners complete a standardisation process. They review a range of candidate
INSTRUCTIONS responses and discuss the mark scheme in detail to agree which answers can and cannot be accepted.
● Answer all questions. Examiners award marks where it is clear that candidate responses have met the requirements of the mark
● Use a black or dark blue pen. scheme. These requirements may vary between different components or different versions of the same
● Write your name, centre number and candidate number in the boxes at the top of the page. component, depending on the exact requirements of the question and the candidate responses seen during
● Write your answer to each question in the space provided. the standardisation process.
● Do not use an erasable pen. Do not use correction fluid or tape.
Sometimes, our mark schemes may allow marks to be awarded to responses which contain elements that
● Do not write on any bar codes. are factually incorrect or for content not covered by the syllabus. We do this in response to the demands of a
● You may use an HB pencil for any diagrams, graphs or rough working. specific question to support candidates and make sure that our assessments are fair. However, these
● Calculators must not be used in this paper. allowances should not be used as a guide for teaching and learning.
We cannot discuss the mark scheme with schools, and we recommend that schools read the mark scheme
INFORMATION together with the assessment material and the Principal Examiner Report for Teachers.
● The total mark for this paper is 75.
● The number of marks for each question or part question is shown in brackets [ ].
● No marks will be awarded for using brand names of software packages or hardware.
This document has 16 pages. Any blank pages are indicated.
DC (WW/JG) 379966/4 This document consists of 17 printed pages.
Cambridge University Press & Assessment 2026 [Turn over
Cambridge University Press & Assessment 2026 [Turn over
, 9618/12 Cambridge International AS & A Level – Mark Scheme May/June 2026
2 PUBLISHED
General marking principles
1 (a) Tick (3) one box to identify the correct definition of a pixel in a bitmap image.
All examiners must apply these marking principles when marking candidate responses.
a colour in an image
1 Examiners must award marks for each response in line with:
a row of consecutive identical colours in an image
• the specific content defined in the mark scheme
the binary code for one colour in an image • the specific skills defined in the mark scheme or in the level descriptions
• the standard of response required as exemplified by the standardisation scripts.
the smallest element of an image that can be one colour
[1] 2 Examiners must award whole marks (not half marks, or other fractions).
3 Examiners must award marks positively. This means that:
(b) Describe the difference between the terms image resolution and screen resolution.
• marks are not deducted for errors or omissions
................................................................................................................................................... • marks are awarded for correct/valid answers as defined in the mark scheme and also for other valid answers which go beyond the
scope of the syllabus and mark scheme referring to your team leader as appropriate
................................................................................................................................................... • the quality of spelling, punctuation and grammar are judged only when the mark scheme indicates that these features are specifically
assessed in the question. However, the meaning of all responses must be unambiguous.
...................................................................................................................................................
4 Examiners must consistently apply the requirements of the mark scheme and any rules for what to do when candidates have not followed
............................................................................................................................................. [2] instructions correctly.
5 Examiners must use the full range of marks defined in the mark scheme, unless limited by the quality of the candidate responses seen.
Two items in a bitmap image file header are the resolution and colour depth.
6 Examiners must award marks according to the mark scheme and must not award marks with grade thresholds or grade descriptions in
Identify one other item included in the file header of a bitmap image. mind.
...................................................................................................................................................
............................................................................................................................................. [1]
Cambridge University Press & Assessment 2026 Page 2 of 17
Cambridge University Press & Assessment 2026 9618/12/M/J/26
, 9618/12 Cambridge International AS & A Level – Mark Scheme May/June 2026
3 PUBLISHED
Annotations guidance for centres
(d) The following bitmap image is created. Each letter represents a colour: R is red, W is white,
B is blue. Examiners use a system of annotations as a shorthand for communicating their marking decisions to one another. Examiners are trained during the
standardisation process on how and when to use annotations. The purpose of annotations is to inform the standardisation and monitoring
processes and guide the supervising examiners when they are checking the work of examiners within their team. The meaning of annotations and
R R W W W W how they are used is specific to each component and is understood by all examiners who mark the component.
B B R R W W We publish annotations in our mark schemes to help centres understand the annotations they may see on copies of scripts. Note that there may
not be a direct correlation between the number of annotations on a script and the mark awarded. Similarly, the use of an annotation may not be an
indication of the quality of the response.
W W W R R R
The annotations listed below were available to examiners marking this component in this series.
W W W W R R
Annotations
W W R R R R
Annotation Meaning
R R R R R B Correct
B B B B B B Incorrect
(i) Identify the smallest bit depth that can be used for the image shown. To indicate where a key word/phrase/code is missing.
..................................................................................................................................... [1]
Not relevant or used to separate parts of an answer.
(ii) Explain how the image shown can be compressed using lossless compression.
Indicates a part of the answer that is incorrect.
...........................................................................................................................................
Highlighter To draw attention to a particular aspect or to indicate where parts of an answer have been combined.
...........................................................................................................................................
Too vague.
...........................................................................................................................................
Repetition
...........................................................................................................................................
No examples or not enough.
...........................................................................................................................................
..................................................................................................................................... [3]
Cambridge University Press & Assessment 2026 Page 3 of 17
Cambridge University Press & Assessment 2026 9618/12/M/J/26 [Turn over
COMPUTER SCIENCE 9618/12
Paper 1 Theory Fundamentals May/June 2026
MARK SCHEME
Maximum Mark: 75
*
COMPUTER SCIENCE 9618/12
Paper 1 Theory Fundamentals May/June 2026 Published
1 hour 30 minutes
You must answer on the question paper.
This mark scheme contains the instructions and marking guidance that our examiners used to mark
No additional materials are needed. candidate responses for this component.
*
Before they start marking, examiners complete a standardisation process. They review a range of candidate
INSTRUCTIONS responses and discuss the mark scheme in detail to agree which answers can and cannot be accepted.
● Answer all questions. Examiners award marks where it is clear that candidate responses have met the requirements of the mark
● Use a black or dark blue pen. scheme. These requirements may vary between different components or different versions of the same
● Write your name, centre number and candidate number in the boxes at the top of the page. component, depending on the exact requirements of the question and the candidate responses seen during
● Write your answer to each question in the space provided. the standardisation process.
● Do not use an erasable pen. Do not use correction fluid or tape.
Sometimes, our mark schemes may allow marks to be awarded to responses which contain elements that
● Do not write on any bar codes. are factually incorrect or for content not covered by the syllabus. We do this in response to the demands of a
● You may use an HB pencil for any diagrams, graphs or rough working. specific question to support candidates and make sure that our assessments are fair. However, these
● Calculators must not be used in this paper. allowances should not be used as a guide for teaching and learning.
We cannot discuss the mark scheme with schools, and we recommend that schools read the mark scheme
INFORMATION together with the assessment material and the Principal Examiner Report for Teachers.
● The total mark for this paper is 75.
● The number of marks for each question or part question is shown in brackets [ ].
● No marks will be awarded for using brand names of software packages or hardware.
This document has 16 pages. Any blank pages are indicated.
DC (WW/JG) 379966/4 This document consists of 17 printed pages.
Cambridge University Press & Assessment 2026 [Turn over
Cambridge University Press & Assessment 2026 [Turn over
, 9618/12 Cambridge International AS & A Level – Mark Scheme May/June 2026
2 PUBLISHED
General marking principles
1 (a) Tick (3) one box to identify the correct definition of a pixel in a bitmap image.
All examiners must apply these marking principles when marking candidate responses.
a colour in an image
1 Examiners must award marks for each response in line with:
a row of consecutive identical colours in an image
• the specific content defined in the mark scheme
the binary code for one colour in an image • the specific skills defined in the mark scheme or in the level descriptions
• the standard of response required as exemplified by the standardisation scripts.
the smallest element of an image that can be one colour
[1] 2 Examiners must award whole marks (not half marks, or other fractions).
3 Examiners must award marks positively. This means that:
(b) Describe the difference between the terms image resolution and screen resolution.
• marks are not deducted for errors or omissions
................................................................................................................................................... • marks are awarded for correct/valid answers as defined in the mark scheme and also for other valid answers which go beyond the
scope of the syllabus and mark scheme referring to your team leader as appropriate
................................................................................................................................................... • the quality of spelling, punctuation and grammar are judged only when the mark scheme indicates that these features are specifically
assessed in the question. However, the meaning of all responses must be unambiguous.
...................................................................................................................................................
4 Examiners must consistently apply the requirements of the mark scheme and any rules for what to do when candidates have not followed
............................................................................................................................................. [2] instructions correctly.
5 Examiners must use the full range of marks defined in the mark scheme, unless limited by the quality of the candidate responses seen.
Two items in a bitmap image file header are the resolution and colour depth.
6 Examiners must award marks according to the mark scheme and must not award marks with grade thresholds or grade descriptions in
Identify one other item included in the file header of a bitmap image. mind.
...................................................................................................................................................
............................................................................................................................................. [1]
Cambridge University Press & Assessment 2026 Page 2 of 17
Cambridge University Press & Assessment 2026 9618/12/M/J/26
, 9618/12 Cambridge International AS & A Level – Mark Scheme May/June 2026
3 PUBLISHED
Annotations guidance for centres
(d) The following bitmap image is created. Each letter represents a colour: R is red, W is white,
B is blue. Examiners use a system of annotations as a shorthand for communicating their marking decisions to one another. Examiners are trained during the
standardisation process on how and when to use annotations. The purpose of annotations is to inform the standardisation and monitoring
processes and guide the supervising examiners when they are checking the work of examiners within their team. The meaning of annotations and
R R W W W W how they are used is specific to each component and is understood by all examiners who mark the component.
B B R R W W We publish annotations in our mark schemes to help centres understand the annotations they may see on copies of scripts. Note that there may
not be a direct correlation between the number of annotations on a script and the mark awarded. Similarly, the use of an annotation may not be an
indication of the quality of the response.
W W W R R R
The annotations listed below were available to examiners marking this component in this series.
W W W W R R
Annotations
W W R R R R
Annotation Meaning
R R R R R B Correct
B B B B B B Incorrect
(i) Identify the smallest bit depth that can be used for the image shown. To indicate where a key word/phrase/code is missing.
..................................................................................................................................... [1]
Not relevant or used to separate parts of an answer.
(ii) Explain how the image shown can be compressed using lossless compression.
Indicates a part of the answer that is incorrect.
...........................................................................................................................................
Highlighter To draw attention to a particular aspect or to indicate where parts of an answer have been combined.
...........................................................................................................................................
Too vague.
...........................................................................................................................................
Repetition
...........................................................................................................................................
No examples or not enough.
...........................................................................................................................................
..................................................................................................................................... [3]
Cambridge University Press & Assessment 2026 Page 3 of 17
Cambridge University Press & Assessment 2026 9618/12/M/J/26 [Turn over
