📑 On This Page
🖨️ What Are Plot Styles?
When AutoCAD sends your drawing to a printer or PDF, it doesn't just print lines as-is. A plot style controls exactly how each line looks on paper: its lineweight (thickness), color (black vs. colour vs. screened grey), linetype, fill style, and even end-cap shape. Without a plot style, what you see on screen is not necessarily what you get on paper.
Plot styles are stored in Plot Style Table files — small data files that AutoCAD attaches to each layout tab. There are two completely separate file formats:
CTB .ctb
Color-Dependent Plot Style Table
- Each of AutoCAD's 255 index colours maps to a lineweight and print colour
- You control lineweight by choosing what colour you draw in
- Industry standard for most architectural and civil practices
- Simple to learn — change a colour, change a lineweight
- One CTB file applies universally; no per-object settings needed
- All objects on the same colour always print identically
STB .stb
Named Plot Style Table
- You create named styles (e.g., "Heavy", "Hidden", "Screened") and assign them to objects or layers directly
- Lineweight is attached to the object or layer, not its colour
- Two objects with the same colour can print at different weights
- More flexible for complex multi-discipline drawings
- Requires more setup and is harder to retrofit to existing drawings
- Used widely in BIM-adjacent workflows and some engineering offices
⚠ You cannot mix CTB and STB in the same drawing. The drawing either uses one type or the other, controlled by the PSTYLEMODE system variable. Switching types requires running CONVERTSTYLES.
⚖️ CTB vs STB: Which Should You Use?
For the vast majority of drafting work — especially in architectural, engineering, and civil utility environments — CTB is the right choice. Here's why:
| Factor | CTB ✅ Recommended | STB |
|---|---|---|
| Learning curve | Low — just match colour to lineweight | Higher — must set up named styles and assign them |
| New drawings | Works immediately with default acad.ctb | Requires setup before drawing |
| Shared files (clients, contractors) | CTB is universal — almost everyone uses it | STB tables may not transfer with the drawing |
| Retrofitting existing drawings | Instant — just swap the CTB file | Requires assigning plot styles to every layer/object |
| Multi-colour output | Possible — set each colour to print as itself | Possible — named styles can carry colour overrides |
| Objects same colour, different weight | Not possible | Yes — assign different named styles |
| Template/standard compatibility | Industry templates almost always use CTB | Some BIM and structural templates use STB |
Bottom line: Start with CTB. Use the same colour-to-lineweight mapping across all your drawings. Only move to STB if you have a specific reason — such as a client or firm standard that requires it, or a drawing where two objects share a colour but need different lineweights.
🎨 How CTB Works
A CTB file is a lookup table. AutoCAD reads the colour of each object and checks the table to find out what lineweight and print colour to use. The colour you draw in on screen is just a key — it doesn't have to be the printed colour.
The typical professional approach:
- ▸ Red (colour 1) → 0.05 mm (hairline — for dimension lines, hatching, notes)
- ▸ Yellow (colour 2) → 0.09 mm (extra fine — text, small details)
- ▸ Green (colour 3) → 0.13 mm (fine — standard annotation)
- ▸ Cyan (colour 4) → 0.18 mm (medium fine — secondary objects)
- ▸ Blue (colour 5) → 0.25 mm (medium — general linework)
- ▸ Magenta (colour 6) → 0.35 mm (medium heavy — important elements)
- ▸ White/Black (colour 7) → 0.50 mm (heavy — walls, outlines, borders)
- ▸ Grey (colour 8 or 9) → 0.70 mm (extra heavy — site boundaries, section cuts)
Everything prints as black regardless of screen colour, unless you specifically configure a colour to print in colour.
💡 The key insight: With CTB you're never really drawing in "red" — you're drawing at hairline weight. Colour is just a visual code for lineweight. Senior drafters develop muscle memory: dimension lines go on a red layer, walls go on a white/heavy layer, etc.
📁 Standard CTB Files Included with AutoCAD
AutoCAD ships with several ready-made CTB files. You can use them as-is or copy and customise them. They live at:
C:\Users\[username]\AppData\Roaming\Autodesk\AutoCAD 2024\R24.3\enu\Plotters\Plot Styles\
| File | What It Does | When to Use |
|---|---|---|
acad.ctb |
Default table — all colours print as black with a default lineweight (usually 0.25 mm). No per-colour mapping configured. | Starting point only. You should customise a copy for your office standard. |
monochrome.ctb |
All 255 colours print as solid black at the object's own lineweight property. | When lineweights are stored on the layers/objects themselves rather than via colour mapping. |
Screening 100%.ctb |
Prints colours at full intensity (essentially colour output). | Colour PDF output — presentations, GIS overlays, utility colouring. |
Screening 75%.ctbScreening 50%.ctbScreening 25%.ctb |
Reduces all colours to screened grey at the named percentage. | Printing background/reference drawings at a lighter weight to distinguish from active drawing content. |
grayscale.ctb |
Converts all screen colours to equivalent greyscale values. | Greyscale PDF output while preserving visual colour differentiation. |
Fill Patterns.ctb |
Maps colours to fill patterns (dithered). | Rarely used in modern workflows — legacy pen plotter patterns. |
Best practice: Copy
acad.ctb, rename it to your firm's standard (e.g., NV5_Standard.ctb), and set up your colour-to-lineweight mapping once. Store it in a shared network folder and point all workstations to it via Options → Files → Plot Style Table Search Path.✏️ Recommended CTB Lineweight Mapping
This is the mapping used in standard Australian/metric architectural and civil drawing practice. ISO lineweights are used. All colours print as black unless noted.
| ACI Colour | Colour Name | Printed Weight | Typical Use | Print Colour |
|---|---|---|---|---|
| 1 | Red | 0.05 mm | Dimension lines, hatch borders, leaders, revision clouds | Black |
| 2 | Yellow | 0.09 mm | Text (small), grid numbers, sheet key marks | Black |
| 3 | Green | 0.13 mm | General annotation, door/window tags, room names | Black |
| 4 | Cyan | 0.18 mm | Minor linework, medium-detail objects, section indicators | Black |
| 5 | Blue | 0.25 mm | Standard object lines, furniture, fittings | Black |
| 6 | Magenta | 0.35 mm | Important objects, property lines, services | Black |
| 7 | White | 0.50 mm | Walls (plan), primary outlines, building footprints, borders | Black |
| 8 | Dark Grey | 0.70 mm | Site boundaries, section cut lines, main title borders | Black |
| 9 | Light Grey | 0.13 mm (screened 40%) | Background grids, existing structures, demolished elements | Grey (screened) |
| 10–18 | Shades of red | 0.05 mm | Supplementary drawing marks | Black |
| 150–165 | Medium blue range | 0.18 mm (colour) | Water/hydraulic utility linework (keep in colour for colour PDFs) | Blue (colour) |
| 30 | Orange | 0.35 mm (colour) | Gas utility / communications (colour output) | Orange (colour) |
| 250–255 | Near-white/near-black | 0.25 mm | General use, xref content | Black |
Note: ISO standard lineweights are: 0.13, 0.18, 0.25, 0.35, 0.50, 0.70, 1.00, 1.40, 2.00 mm. Stick to these values for professional results. Non-standard values like 0.15 mm or 0.4 mm can look inconsistent across different plotters.
⚙️ Creating & Editing a CTB File
Open the Plot Style Table Editor
There are three ways to get there:
A
From the command lineType
STYLESMANAGER → Enter. Windows Explorer opens showing the Plot Styles folder. Double-click any .ctb file to open the editor.B
From the Plot dialogOpen Plot dialog (
PLOT) → click the small button next to the Plot Style Table dropdown → select Edit. Or choose a table then click the edit icon (pencil).C
From Page SetupType
PAGESETUP → select a layout → click Modify → use the Plot Style Table dropdown and edit button.Create a new CTB from scratch
1
Type STYLESMANAGER and press EnterThe Plot Styles folder opens in Windows Explorer.
2
Double-click "Add-A-Plot-Style-Table-Wizard"The wizard launches. Click Next.
3
Choose "Start from scratch" → NextOther options let you import from a PCP/PC2 file or copy an existing table.
4
Select "Color-Dependent Plot Style Table" → NextThis creates a .ctb file. Choose "Named Plot Style Table" for .stb.
5
Enter a filename (e.g., "Office_Standard") → NextThe file will be saved as Office_Standard.ctb
6
Click "Plot Style Table Editor" → FinishThe editor opens immediately so you can configure your colour mappings.
Configure lineweights in the editor
Plot Style Table Editor — Office_Standard.ctb
✕
Plot styles:
Color_1
Color_2
Color_3
Color_4
Color_5
Color_6
Color_7
Properties for Color_1 (Red):
Color:Black
Dither:On
Grayscale:Off
Pen #:Automatic
Screening:100
Linetype:Use object linetype
Lineweight:0.0500 mm
Line end style:Use object end style
Fill style:Use object fill style
Click each colour in the left list and set its properties in the right panel. The key fields are:
| Property | Recommended Setting | Notes |
|---|---|---|
| Color | Black | Set to "Black" for all standard linework. Set to a specific colour only for colour output (e.g., utility mains). |
| Lineweight | ISO value per colour | Use the ISO series: 0.05, 0.09, 0.13, 0.18, 0.25, 0.35, 0.50, 0.70 mm. Select from the dropdown — don't type arbitrary values. |
| Screening | 100 (unless screened) | 100 = full. 50 = 50% grey screen. Use for existing/background elements. |
| Linetype | Use object linetype | Leave as "Use object linetype" — let the layer control this. |
| Fill style | Use object fill style | Leave as default. |
Bulk edit tip: Hold
Ctrl or Shift and click multiple colours in the left panel. Any property change then applies to all selected colours at once — great for setting all 255 colours to "Black" in one click.🏷️ How STB Works
In a drawing set to use STB, each object and layer has a Plot Style property (visible in the Properties panel and Layer Manager). This property points to a named style in the attached STB file. The named style then defines how that object prints.
Example STB named styles:
Style: Heavy
- Colour: Black
- Lineweight: 0.50 mm
- Screening: 100%
- Used on: WALL, BORDER layers
Style: Hairline
- Colour: Black
- Lineweight: 0.05 mm
- Screening: 100%
- Used on: DIM, HATCH layers
Style: Screened-50
- Colour: Black
- Lineweight: 0.13 mm
- Screening: 50%
- Used on: XREF, EXIST layers
Style: Normal
- Colour: Use object colour
- Lineweight: Use object lineweight
- Screening: 100%
- Default style — prints as-is
STB key difference: In STB mode, the layer colour is purely visual — it has no effect on lineweight or print colour. You can draw everything in white, and as long as the correct named plot style is assigned, it will print correctly.
⚙️ Creating & Editing an STB File
The process mirrors CTB creation, but you'll be adding named styles instead of configuring colours.
1
Type STYLESMANAGER → EnterPlot Styles folder opens.
2
Double-click "Add-A-Plot-Style-Table-Wizard" → NextSelect "Start from scratch" → Next.
3
Select "Named Plot Style Table" → NextThis creates an .stb file.
4
Enter a filename → click "Plot Style Table Editor"The editor opens. You'll see one default style: "Normal".
5
Click "Add Style" for each named style you needName them clearly: Heavy, Medium, Fine, Hairline, Screened-50, etc. Set properties for each.
6
Save & CloseAssign the STB to your layout via PAGESETUP, then assign named styles to layers in the Layer Manager.
Assigning styles to layers: After attaching an STB, open the Layer Manager. You'll see a new "Plot Style" column. Click the style name for each layer and choose the correct named style. Without this step, everything defaults to "Normal" and prints at the object's own lineweight.
📄 Assigning a Plot Style Table to a Layout
A CTB or STB file is assigned per layout tab — not to the whole drawing. The Model tab rarely needs a plot style (it's for working, not printing). Each paper space layout should have the correct table assigned.
Method 1: Page Setup Manager (recommended)
1
Right-click a layout tab → "Page Setup Manager"Or type
PAGESETUP at the command line.2
Select the layout → click "Modify"The Page Setup dialog opens.
3
Find the "Plot Style Table (pen assignments)" sectionIt's in the upper-right area of the dialog. Click the dropdown.
4
Select your CTB or STB file from the listAll .ctb and .stb files in your Plot Styles folder will appear. If yours isn't listed, check the search path in Options → Files.
5
Tick "Display plot styles" if you want to preview on screenThis makes the viewport show approximate lineweights — useful for visual checking before printing.
6
Click OK → CloseThe layout now uses your plot style table. Repeat for each layout tab.
Method 2: From the Plot dialog
When you open PLOT, the same Plot Style Table dropdown appears at the upper right. Changing it here updates the layout's page setup for that session, but you should confirm it's saved via Page Setup Manager for consistency.
; Quick check: what plot style table is assigned to current layout?
Command: PAGESETUP
; Or check via Properties — click the layout viewport
Command: PROPERTIES
; The "Plot style table" field shows the attached CTB/STB
Template tip: Set your plot style table in your drawing template (.DWT file) so it's automatically applied to every new layout. You'll never have to set it per drawing again.
🔄 Converting CTB ↔ STB
If you receive a drawing that uses STB and you need it to use CTB (or vice versa), AutoCAD provides the CONVERTSTYLES command. CAUTION
CONVERTSTYLES is a one-way destructive operation per session. You cannot undo it after saving. Always work on a copy of the drawing. Back up before converting.
Convert STB → CTB
1
Open the drawing (work on a copy)Confirm PSTYLEMODE = 0 (the drawing uses named/STB styles).
2
Type CONVERTSTYLES → EnterAutoCAD asks you to confirm the conversion. Read the warning carefully.
3
Select a CTB file to attachAutoCAD replaces the STB assignment with the CTB you choose. Named plot style properties on layers are cleared.
4
Save the drawingPSTYLEMODE is now 1. The drawing is CTB-based.
Convert CTB → STB
The process is the same in reverse — run CONVERTSTYLES on a CTB drawing and point it to an STB file. However, the colour-based lineweights are not automatically transferred to named styles — you must manually assign plot styles to layers after conversion.
AutoCAD also ships a separate utility: CONVERTPSTYLES — this converts the plot style table format of individual page setups without changing the whole drawing mode. Less commonly needed.
⌨️ System Variables
PSTYLEMODE
0 = Named (STB) | 1 = Color-Dependent (CTB)
Read-only — shows which plot style mode the current drawing uses. Cannot be changed directly; use CONVERTSTYLES to switch.
PSTYLEPOLICY
0 = Use object's plot style | 1 = Use layer's plot style
Controls whether plot styles on individual objects or their layer take precedence. Default is 1 (layer wins). Relevant only in STB mode.
PLOTSTYLE
String (style name)
The current default plot style assigned to new objects (STB mode only). In CTB mode this is always "ByColor".
PLOTTRANSPARENCY
0 = Off | 1 = On
Controls whether AutoCAD plots object transparency values. Transparency plotting is slow — leave Off unless you specifically need it. Set to 0 in the Plot dialog to speed up PDF output.
SHOWPLOTSTYLES
0 = Off | 1 = On
When On, the viewport displays an approximation of the plot style lineweights. Useful for visual proofing, but can slow down screen performance on large drawings.
LWDISPLAY
0 = Off | 1 = On
Toggles whether layer lineweight properties are displayed on screen. Shortcut: click the LWT button in the status bar. This is the layer lineweight — separate from the plot style lineweight.
🔧 Troubleshooting
| Problem | Likely Cause | Fix |
|---|---|---|
| Everything prints at the same lineweight | All colours are set to "Use object lineweight" in the CTB, or no CTB is assigned | Open the CTB in the editor and set explicit lineweight values per colour. Confirm a CTB is assigned in Page Setup. |
| Drawing prints in colour instead of black | CTB has colours set to "Use object color" instead of "Black" | Open the CTB editor → select all colours (Ctrl+A) → set Color to "Black" → Save. |
| Plot Style Table dropdown is empty or shows "None" | CTB/STB files are not in AutoCAD's search path, or no table is assigned | Options → Files → Plot Style Table Search Path. Add the folder containing your CTB files. Or move CTB files to the default Plotters\Plot Styles\ folder. |
| Lineweights look correct on screen but wrong when plotted | "Display plot styles" is off — screen shows object lineweights, not CTB lineweights. Or the wrong CTB is selected at plot time. | In Page Setup, tick "Display plot styles". Confirm the correct CTB is selected in the Plot dialog at print time. |
| Can't change the plot style property on a layer | Drawing is in CTB mode (PSTYLEMODE=1) — layer plot styles are fixed to "ByColor" and not editable | This is correct CTB behaviour. To use named styles, convert to STB with CONVERTSTYLES. |
| Plot styles dropdown shows .stb files instead of .ctb | The drawing was created in STB mode (PSTYLEMODE=0) | Run CONVERTSTYLES and select a CTB file. Or open a new drawing template set to CTB mode. |
| Received drawing has no lineweight on plot | Sender used monochrome.ctb with all lineweights set to "Use object lineweight" — and object lineweights are all "Default" | Assign your office CTB via Page Setup. If still wrong, set lineweights on the layers themselves in the Layer Manager. |
| PDF looks perfect but print on paper is wrong weights | PDF uses a different plot style table than the physical printer page setup | Use Page Setup Manager — create two page setups (one for PDF, one for printer) and select each appropriately when printing. |
| CTB file changes don't seem to take effect | The CTB file is cached; or you edited a different copy of the file than the one AutoCAD is using | Close and reopen the drawing. Run STYLESMANAGER to confirm which folder AutoCAD is reading from. Check Options → Files path. |
Checking what CTB is currently active
; Open Page Setup Manager for the current layout
Command: PAGESETUP
; Click Modify — the Plot Style Table field shows the active CTB/STB
; Or check via the command line (returns the path to the active plot style table) Command: _PLOT ; then look at Plot Style Table in the dialog
; Find the Plot Styles folder Command: STYLESMANAGER
; Or check via the command line (returns the path to the active plot style table) Command: _PLOT ; then look at Plot Style Table in the dialog
; Find the Plot Styles folder Command: STYLESMANAGER
Plot Style Table missing on another computer
If you send a drawing to a colleague and their PDF or print looks different, they almost certainly don't have your CTB file. CTB files are not embedded in the DWG — they're separate files that must be present on each machine.
1
Copy your .ctb file to the colleague's machinePlace it in:
C:\Users\[username]\AppData\Roaming\Autodesk\AutoCAD 2024\R24.3\enu\Plotters\Plot Styles\2
Or store CTB on a shared network pathOptions → Files → Plot Style Table Search Path → add the network folder. All staff then share one master CTB — changes instantly apply to everyone.
3
Or use ETRANSMITAutoCAD's ETRANSMIT command packages the DWG together with all dependencies including the CTB file — ready to send to a client or contractor.
✅ Best Practices
1. Standardise on one CTB file for your office. Name it after your firm or project standard (e.g.,
NV5_Standard.ctb). Store it in a shared network location. Never use acad.ctb as your production table — it's a generic default, not a controlled standard.
2. Map colours to ISO lineweights. Colours 1–9 map to ISO weights 0.05 → 0.70 mm. This is the unwritten industry standard. Anyone who opens your drawing and knows CTB conventions instantly understands your layer colour coding.
3. Set the CTB in your DWT template. Open your template, set the plot style in Page Setup, save. Every new drawing will inherit the correct plot style from day one.
4. Use "Display plot styles" in Page Setup. Tick this so your screen reflects actual print output. Visual proofing before printing catches lineweight problems immediately.
5. Never rely on object lineweights with CTB. In CTB mode, lineweight comes from the CTB — not from the layer or object's lineweight property. Set all layer lineweights to "Default" to avoid confusion.
6. For colour PDFs (utility work): Set specific high-use utility colours (water = blue ACI 150, gas = orange ACI 30, comms = green ACI 82) to print in their respective colours in the CTB. Everything else stays black. This gives you one CTB that handles both B&W structural sheets and colour utility sheets.
7. Never send drawings without your CTB. Always use ETRANSMIT when sending to clients or contractors. A drawing without its CTB will print at random lineweights on the recipient's machine.