Alternate Text

Graphs
Complex Data Tables
Charts
Diagrams
Comparing Complex Objects
Flow Chart
Complex Flow Charts
Bar Graph
Scatter Plot

We have compiled multiple resources; for more examples, review Image Description Guidelines.

Overview

Alternate text is best used when MathML is not an option. Students who are blind or low vision may require the use of tactile graphics. It is important to determine what the student learning outcomes are for a given project, and in cases where the answer might be in the alternate text, it might be necessary to rewrite the question differently.

Alternate text is best used with MathML is not an option. Students who are blind or low vision may require the use of tactile graphics. It is important to determine what the student learning outcomes are for a given project, and in cases where the answer might be in the alternate text, it might be necessary to rewrite the question differently. The University of Washington has provided an informational guide on Making Science Labs Accessible to Students with Disabilities.

Goal: This page provides several alternate text samples. After reviewing this page, participants will be able to write a complex alternate text for images based on samples provided.

Image Description Principles

While the content of an image description will depend on the image itself and the item in which it resides, there are some guiding principles to keep in mind when writing image descriptions as a whole.

Validity

Determine if the image needs to be described. In instances where a description does not lend clarity to answer a question or where the surrounding text explains the image, it might suffice to simply state that there is an image (e.g., “There is an image of a car.”) without providing detail.

Brevity

Provide the necessary information for the student to be able to answer the question. Avoid unnecessary long descriptions that do not appear essential to the item and require greater short-term memory effort.

Clarity

Focus on making the image description as clear and straightforward as possible. If the student needs to listen to the description several times because it is presented confusingly, then the image description is not accessible. Always read the whole item to ensure that the image description ties in seamlessly with the rest of the item.

Language Complexity

Use simple, grade-appropriate, subject-related language. Where possible, use language that appears in the item itself and emphasizes the tactile quality of what is depicted in an image.

Drill-Down Organization

Use a drill-down organization when describing an image. Start with the title, give a summary of the image, and then provide specific data or descriptions if necessary.

Graphs

Example of an image containing a graph as an inset. Refer to "Description" below the image for a detailed description of the image.

Adapted from the Diagram Center

Guidelines:

Give a brief overview of the picture, i.e., a basic illustration with an embedded graph, and then provide the detail.
Avoid describing extraneous visual information, ex., one lizard is perched on a rock, there are six lamps on a beam.
Determine if the graph can be sufficiently summarized in a sentence or two. If not, provide the data in a table with row and column headings.
- There are numbers in parentheses that are not explained in the caption or the surrounding text in the graph. They should not be ignored in the description. Include them but do not guess at or assume their meaning.

Description:

A drawing shows two lizards in a confined space. One lizard stands in a shadow, and the other lizard stands beneath a heat lamp. Above the lizards is a multiple line graph. The horizontal X-axis is labeled “time (days).” The vertical Y-axis is labeled “% survived.” There are five separate lines labeled by temperature ranging from 34°C to 42°C and followed by another number in parenthesis in the graph. The following table represents the graph. All data are approximate.

Degrees Celcius	1 Day	2 Days	3 Days	4 Days	5 Days	6 Days	7 Days
42°C (24)	100%	95%	95%	90%	85%	80%	75%
40°C (12)	85%	77%	73%	65%	65%	65%	65%
38°C (36)	60%	40%	35%	30%	25%	25%	25%
36°C (12)	30%	30%	25%	25%	25%	25%	25%
30°C (12)	10%	5%	0%	0%	0%	0%	0%

Complex Data Tables

Complex table sample. Description is below

Guidelines:

While this table is complex with several headings layers, it can be broken into three separate tables under the headings: Motor vehicle traffic, Firearm suicide, and Firearm homicides.
Providing three separate tables will aid in navigation and comprehension.
The table includes two reference notations: a hyphen representing Quantity zero and a superscript, one indicating that SE stands for standard error. To avoid confusion in the tables below, the superscript one and the hyphen were simply replaced with the words “Quantity zero” and “standard error.” This is an example of providing greater clarity as opposed to mimicking the exact visuals of the table.
If desirable, this complex table may also be replicated exactly through proper HTML coding.

Description:Figure 9 is a table titled “Average annual weighted number of deaths and percent distribution of deaths by body region of injury, for motor vehicle traffic accidents, firearm suicides, and firearm homicides: the United States 2003-2004.” For better navigation, the table has been separated into three tables:

*Table 1: Motor Vehicle Traffic*
Body region	Number of deaths	Percent distribution	Standard Error (percent)
Total	43,386	100.0	Quantity Zero
Head and neck	13,862	32.0	0.3
Torso	7,382	17.0	0.3
Other specified	911	2.1	0.3
Spine, upper back	492	1.1	0.3
Extremities	410	1.0	0.3
Unclassifiable by body region	14,691	33.9	0.3
Unspecified	6,540	15.1	0.3

*Table 2: Firearm Suicide*
Body region	Number of deaths	Percent distribution	Standard Error (percent)
Total	16,829	100.0	Quantity Zero
Head and neck	12,428	73.9	0.3
Torso	2,211	13.1	0.5
Other specified	28	0.2	0.5
Spine, upper back	13	0.1	0.5
Extremities	14	0.1	0.5
Unclassifiable by body region	67	0.4	0.5
Unspecified	2,094	12.4	0.5

*Table 3: Firearm Homicide*
Body region	Number of deaths	Percent distribution	Standard Error (percent)
Total	11,772	100.0	Quantity Zero
Head and neck	3,714	31.5	0.5
Torso	4,005	34.0	0.5
Other specified	397	3.4	0.6
Spine, upper back	33	0.3	0.7
Extremities	363	3.1	0.6
Unclassifiable by body region	2,685	22.8	0.6
Unspecified	972	8.3	0.6

Diagram Sample

Guidelines:

Break the information into a bulleted list for easier navigation.
Spell out abbreviated units for clearer audio pronunciation.
Describe the parts of the image rather than explain the concept. That is done in the surrounding text.

Description:

Two diagrams show vectors on a number line. Diagram A shows a number line that goes from 0, the start, to 6, the finish. A vector arrow goes from 0 to 4 and is labeled 4 kilometers. Another vector arrow goes from 4 to 6 in the same direction and is labeled 2 kilometers. The diagram represents the equation: 4 kilometers plus 2 kilometers equals 6 kilometers.
Diagram B shows a number line that goes from 0, the start, to 4. In the middle of the number line, 2 is the finish. A vector arrow goes from 0 to 4 and is labeled 4 kilometers. Another vector arrow goes from 4 to 2 in the opposite direction and is labeled 2 kilometers. The diagram represents the equation: 4 kilometers minus 2 kilometers equals 2 kilometers.

This image in context:

The diagram is used after the concept is introduced.
Captions explain the concept very clearly.

Comparing Complex Objects

A diagram depicting the differences of ten different birds

Guidelines:

The various relationships between the finches can be replicated in a table.
This is a case in which the table requires more work to discern the relationships than the illustration. A b/vi person would have to review the table several times to establish the sighted person's patterns almost instantly. However, the table does allow for a quick review of data that a narrative-style description would not.
This table, like all tables, can be rendered differently. In this case, the alternate would be to have the categories run down the left-hand column instead of across the top row.
If the finches’ feathers' colors are important, an additional column can be added to the table.

Description:

An illustration showing 10 different finches and their variations is depicted in the following table.

Adaptive Radiation: Darwin’s Finches

Name	Finch	Bill	Food
Vegetarian tree finch	Tree finches	Parrot-like bills	Fruit eaters
Large insectivorous tree finch	Tree finches	Grasping bills	Insect eaters
Small insectivorous tree finch	Tree finches	Grasping bills	Insect eaters
Woodpecker Finch	Tree finches	Probing bills	Insect eaters
Warbler finch	Warbler finch	Probing bills	Insect eaters
Cactus ground finch	Ground finches	Probing bills	Cactus eaters
Sharp-beaked ground finch	Ground finches	Crushing bills	Seedeaters
Small ground finch	Ground finches	Crushing bills	Seedeaters
Medium ground finch	Ground finches	Crushing bills	Seedeaters
Large ground finches	Ground finches	Crushing bills	Seedeaters

Flow Chart

Guidelines:

Flow charts are a common method of presenting information and one of the most difficult images to describe.
Simple flow charts can be converted into nested lists with good results. Present the “boxes” as numbers and the possible transitions as sub-bullets.
For some people, combining descriptions with a tactile version of a flow chart facilitates comprehension.
It is not necessary to describe the charts' visual attributes, e.g., yellow boxes, curved arrows, etc. unless there is an explicit need such as an exam question referring to these attributes.

Description:

The figure is a flow chart with eight labeled boxes linked by arrows. The chart is multi-directional. At each step, arrows point forward to one or more boxes and back to the previous box or boxes. Here the flow chart is described as lists in which the possible next steps are listed beneath each box label.

Standards
1. forward to Theme
Theme
1. back to Standards
2. forward to Goals/Objectives
Goals/Objectives
1. back to Theme
2. forward to Performance Assessment
Performance Assessment (Interpersonal – Interpretive – Presentational)
1. back to Goals/Objectives
2. forward to Structures/Functions
3. forward to Vocabulary
4. forward to Resources
Structures/Functions
1. back to Performance Assessment
2. lateral to Vocabulary
3. forward to Instructional Strategies
Vocabulary
1. back to Performance Assessment
2. lateral to Structures/Functions
3. lateral to Resources
4. forward to Instructional Strategies
Resources
1. back to Performance Assessment
2. lateral to Vocabulary
3. forward to Instructional Strategies
Instructional Strategies
1. back to Structures/Functions
2. back to Vocabulary
3. back to Resources

Complex Flow Chart

A diagram of the photosynthesis process showing the steps in two cycles. The content is further explained below

Guidelines:

This illustration shows a process. One way to make this accessible is to lay out the steps in a list, similar to the recommendation for flow charts.
Again, the illustration itself is colorful and visually interesting, but it doesn’t provide additional information beyond the data.

Description:

The Krebs Cycle is depicted as a linear reaction that leads down into a cyclical reaction. Here, the steps of the reactions are presented as lists.

Linear Reaction
- Pyruvic acid, a 3-carbon compound.
- One carbon molecule is lost as part of a CO2 molecule.
- A NAD-positive molecule enters the reaction, then leaves as NADH.
- A 2-carbon acetyl group remains.
- Coenzyme A, or CoA, joins the 2-carbon acetyl group to form Acetyl CoA.
- CoA leaves the reaction as it delivers the acetyl group to the circular reaction.
Circular Reaction
- The two-carbon acetyl group joins a four-carbon compound to form a 6-carbon compound, citric acid.
- Carbon is lost as CO2.
- NAD-positive enters, then leaves as NADH.
- A 5-carbon compound remains.
- Another carbon is lost as CO2.
- NAD-positive comes in and leaves as NADH.
- ADP comes in and leaves as ATP.
- A four-carbon compound remains.
- FAD comes in and leaves as FADH2.
- NAD-positive comes in and leaves as NADH.
- At the top of the circular reaction, a two-carbon acetyl group from the linear reaction enters, forming the 6-carbon citric acid at the beginning of the cycle.

Bar Graphs

An example of a vertical Bar Graph. The content is explained in this section.

Guidelines:

Bar graphs should be converted into accessible tables.
Briefly describe the graph and give a summary if one is immediately apparent.
Provide the title and axis labels.
It is not necessary to describe the bars' visual attributes, e.g., dark blue, light blue unless there is an explicit need such as an exam question referring to the colors.

Description:

Figure 1 is a bar graph that measures vaccination coverage percentage in five states over one year, from Q3 2006 to Q2 2007. In each state, the coverage increases over time. The data are summarized in the following table. All data are approximate.

*First dose rotavirus vaccination coverage among children aged 3 months, by a quarter – immunization information system (IIS) sentinel sites, United States, 2006-2007.*
blank space	Arizona	District of Columbia	Michigan	Minnesota	Montana	Oregon
Q3 2006	35%	10%	5%	0%	15%	20%
Q4 2006	45%	30%	33%	25%	27%	27%
Q1 2007	50%	45%	42%	35%	37%	45%
Q2 2007	65%	48%	50%	41%	40%	44%

Scatter Plots

A scatter plot graph that shows the relationship between annual rainfall and plant tissue growth

Guidelines:

Scatter plots are among the more difficult graphs to describe, especially if there is a need to make specific data points accessible.
Provide the title and axis labels.
Identify the image as a scatter plot and focus on the change of concentration.
If it is necessary to be more specific, convert the data into an accessible table.

Description:

The graph is a scatter plot entitled “Rainfall and Plant Growth.”The horizontal X-axis shows Average Rainfall ranging from zero to four thousand, in units of millimeters per year, in increments of one thousand. The vertical Y-axis shows Plant Tissue Production in units of grams per meter squared per year, ranging from zero to three thousand, in increments of five hundred. The graph has approximately 85 points scattered in a pattern beginning in the lower-left corner where Plant Tissue Production and Average Rainfall are the lowest. The pattern extends toward the upper-right corner where Plant Tissue Production and Average Rainfall are the highest. The majority of points are concentrated in the lower-left corner and diminish in concentration as the pattern extends toward the upper-right corner.

Updated 4.22.2025