Plot Styles & Lineweights Guide
If your drawing looks right on screen but prints with the wrong colors or line thicknesses, plot styles are often the reason. CTB and STB files tell CAD how objects should look on the final PDF or paper sheet, while lineweights add the visible hierarchy that makes a technical drawing readable.
If your drawing looks right on screen but prints with the wrong colors or line thicknesses, plot styles are often the reason. CTB and STB files tell CAD how objects should look on the final PDF or paper sheet, while lineweights add the visible hierarchy that makes a technical drawing readable.
Start here — what you are going to do
Your goal: Make the PDF or paper use the intended colors, black/white output and line thicknesses.
Where to go: AutoCAD Layout > Output > Plot > Page Setup Manager > Modify > Plot Style Table.
Beginner rule: Change one thing at a time. After each important change, use Preview or create one test PDF/print before continuing.
Step by step — follow this in order
Step 1 — Open the Layout and its Page Setup
Where: Layout tab > Output > Plot > Page Setup Manager > select setup > Modify.
Do this: Do not start by editing object colors. First check which plot style is assigned to the Layout.
Check: The Page Setup dialog should show a Plot Style Table field.
Step 2 — Check whether you are using CTB or STB
Where: Page Setup dialog > Plot Style Table list.
Do this: If you see .ctb choices, the drawing uses color-dependent plot styles. If it uses named styles, work with STB.
Check: You should know which system controls this drawing before editing anything.
Step 3 — Choose the intended style table
Where: Plot Style Table list.
Do this: Select the approved CTB/STB. For monochrome output, use the approved monochrome CTB if that is your office standard.
Check: The selected style should remain assigned to the Page Setup.
Step 4 — Make sure plot styles and lineweights are enabled
Where: Page Setup dialog > Plot Options.
Do this: Enable the options required by your standard, such as plotting with plot styles and plotting object lineweights.
Check: Plot Preview should begin reflecting the intended thickness/color rules.
Step 5 — Preview one known object
Where: Click Preview from Plot.
Do this: Pick one wall, border or other known line and compare it with the expected lineweight.
Check: If only one object is wrong, check its layer/object override before changing the whole CTB/STB.
Step 6 — Test with a small lineweight ladder
Where: Use a calibration DWG or create a small group of lines with known lineweights.
Do this: Plot the test to PDF and, if needed, to the physical plotter.
Check: The hierarchy should be clear: thin lines remain thin and heavy lines remain visibly stronger.
A simple example
CTB office standard
A color-dependent office standard might reserve specific indexed colors for thin, medium and heavy plotted weights. The CTB then maps those colors to the approved output properties. If users bypass the color convention with arbitrary object colors or overrides, the same CTB no longer guarantees the same hierarchy.
STB office standard
An STB workflow can let display color vary independently from plotted style. That is useful when the team wants named styles such as Thin, Medium or Existing instead of encoding output behavior in indexed colors, but every participating drawing must follow the same named-style logic.
The parts that control printed appearance
CTB mode
Color-dependent plot styles map indexed colors to plotted properties. The drawing must be in CTB mode to list CTB tables.
STB mode
Named plot styles assign named styles to objects/layers independently of their display color.
Where lineweight comes from
Lineweight can come from object properties, layer properties and plot-style overrides. Diagnose the source before changing values.
Screening / lighter output
Screening reduces plotted intensity and is commonly used for backgrounds, existing conditions and secondary information.
Where the job is printed from
The same nominal lineweight can look different across PDF viewers, laser printers and large-format inkjet devices, so standards need output tests.
How plot styles become printed linework
CTB is a standard, not a magic fix
A CTB only works predictably when layer colors are assigned according to the office standard. If users use arbitrary True Color values or per-object overrides, a color-dependent mapping may not produce the intended hierarchy.
STB decouples style from color
Named plot styles allow display color and plotted style to be managed separately. That can be powerful for standards, but it requires disciplined named-style assignments and compatibility awareness when exchanging DWG files with teams using CTB.
Lineweight ladders
Before defining “best” lineweights, plot a ladder containing representative geometry from roughly hairline through heavy border weights, plus text, hatches and screened objects. Evaluate it on the actual target devices.
Conversion caution
CTB/STB conversion is possible, but a conversion command does not automatically redesign a poor plotting standard. check resulting layer/object assignments and issue-set output after conversion.
Common problems and what to check first
| What you see | What may be causing it | Check this first |
|---|---|---|
| CTB not listed | Drawing is STB-based or CTB is outside Plot Styles path. | Check drawing mode before copying files repeatedly. |
| Everything prints same thickness | Lineweights are not assigned/applied, or CTB maps colors identically. | Trace one test object from layer/object property through plot style. |
| Color prints instead of black | Wrong CTB/STB or plot styles not active. | Verify the selected table and Page Setup options. |
| Thin lines disappear | Device resolution, screening, raster output or too-light weight. | Test a controlled lineweight ladder on the actual device. |
| PDF differs from paper | Driver/viewer/device alters rendering. | Treat PDF and physical output as separate verification stages. |
For office-wide graphic standards
An office standard should clearly say whether drawings are CTB- or STB-based, where the style files live, which layer/object lineweights are allowed and how screened or grayscale output is handled. Test the standard with a lineweight/color sample sheet.
Official references
Frequently asked questions
What is the main difference between CTB and STB?
CTB uses indexed drawing colors to control plotted properties. STB applies named plot styles that are not inherently tied to object color.
Why is my CTB file not listed?
The drawing may use named plot styles, the file may be outside the configured Plot Styles folder, or the expected support path may differ between computers.
Do lineweights come only from CTB files?
No. Objects and layers can have explicit lineweights, and plot styles can override or modify how those properties are printed.
Why can two drawings using the same CTB still look different?
The drawings may use different layer colors, object overrides, lineweights, transparency or Page Setup options. A CTB is only one layer in the plotted result.