How-to guide · how to set up a plot style table ctb
How to set up a plot style table (CTB) in AutoCAD
By Sumana Kumar · Published 9 Apr 2023 · Updated 23 Mar 2026
A CTB — a colour-dependent plot style table — is the file that decides how every colour in your drawing prints. It maps each of AutoCAD's index colours to a printed line weight, a screening percentage and an output colour, so the thick walls, thin grid lines and grey hatching you expect all come from one controlled file rather than from settings scattered through the drawing.
This guide creates a CTB from scratch, assigns line weights colour by colour, and attaches it to a layout so it actually takes effect at plot time. Once you have a CTB tuned to your office standard, every drawing that uses it plots with consistent line weights, which is the single biggest factor in a drawing looking professional.
Understand what a CTB controls
In a colour-dependent workflow, the on-screen colour of an object is the key to how it prints. Red might plot at 0.25 mm, blue at 0.50 mm, and a particular grey colour at 0.13 mm and 50 percent screen for hatching. The CTB holds 255 rows, one per AutoCAD index colour, and each row sets the printed line weight, line type, screening, and whether that colour prints in its own colour or in black.
This is different from the alternative STB (named) system, where a plot style is a named property applied to a layer or object regardless of colour. CTB is the older and still most common convention in shared drawings, which is why getting comfortable with it matters.
Step 1 — Open the Plot Style Manager
Type STYLESMANAGER and press Enter, or go to the application menu under Print > Manage Plot Styles. A Windows folder opens containing the existing plot style tables and a 'Add-A-Plot Style Table' wizard. This folder is where AutoCAD stores every CTB and STB available to your drawings.
You will see standard files like acad.ctb and monochrome.ctb already there. You can copy one of these as a starting point, or run the wizard to build a fresh table. Starting from monochrome.ctb is handy when your office prints everything in black and you only need to vary line weights.
Step 2 — Create a new CTB with the wizard
Double-click 'Add-A-Plot Style Table'. Choose 'Start from scratch', then 'Color-Dependent Plot Style Table' (this is what makes it a CTB rather than an STB). Give the table a clear name — your company name or a project standard works well — and finish the wizard. The new .ctb file lands in the Plot Styles folder.
Tick 'Plot Style Table Editor' on the final wizard page, or open the new CTB later by double-clicking it, to start assigning line weights. This editor is where the actual mapping happens.
Step 3 — Assign line weights colour by colour
In the Plot Style Table Editor, open the 'Form View' tab. The left column lists Color 1 through Color 255. Select a colour, then on the right set its 'Lineweight' to the printed thickness you want — a typical hierarchy runs thin grid and dimension lines around 0.13–0.18 mm, general linework around 0.25 mm, and bold outlines and cut lines around 0.50–0.70 mm.
Set 'Color' to Black if you want that index colour to print black regardless of its screen appearance — the usual choice for a monochrome set. Leave it 'Use object color' for a colour plot. Use 'Screening' (a percentage) to lighten a colour for hatching or background information without changing its line weight. Select several colours at once with Ctrl or Shift to apply the same setting in one go.
Step 4 — Save and attach the CTB to a layout
Click 'Save & Close' in the editor. The CTB now exists, but a drawing will not use it until you assign it. Open a layout, press Ctrl+P, and under 'Plot style table (pen assignments)' choose your new CTB. AutoCAD asks whether to apply it to the current layout or all layouts — choose all layouts to keep a sheet set consistent.
You can also bake the CTB into a Page Setup so it is the default for every plot. Once attached, run a Preview to confirm the line weights look right before you commit a full plot or PDF.
Editing and sharing a CTB across a team
A CTB is a single portable file. To share an office standard, copy the .ctb into each machine's Plot Styles folder (reachable via STYLESMANAGER), or point AutoCAD's plot-style search path at a shared network folder under Options. When you tweak a line weight in the editor, every drawing that references that CTB picks up the change at the next plot — no need to touch the drawings themselves.
Keep your colour-to-weight scheme documented somewhere the team can see it, because the whole CTB system rests on everyone drawing the right things in the right colours. A wall on the wrong colour will plot at the wrong weight, and the fix is in the drawing, not the CTB.
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Questions
Frequently asked
What's the difference between a CTB and an STB?+
A CTB (colour-dependent) maps print settings to each of the 255 AutoCAD colours, so an object's colour controls how it plots. An STB (named) assigns named plot styles to layers or objects independently of colour. A drawing uses one system or the other, not both.
Where are CTB files stored on my computer?+
In the Plot Styles folder, which you can open directly by typing STYLESMANAGER in AutoCAD. Copying a .ctb into that folder on another machine makes it available there too.
How do I make my whole drawing print in black?+
Use monochrome.ctb, or in your own CTB select all 255 colours and set 'Color' to Black. Line weights still vary by colour, but every line prints solid black instead of in its screen colour.
Why didn't my line weights change after editing the CTB?+
The CTB has to be attached to the layout you are plotting. Open the Plot dialog and confirm your CTB is selected under 'Plot style table (pen assignments)'. Editing the file alone does nothing until a layout references it.
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