What "ignoring" a colour does
ZeroCount runs every drawing through some image processing before detection. By default, every colour on the drawing contributes to the working image. Ignored Colours lets you say "treat everything in this colour as background — don't look for symbols there".
It's a precision tool. Use it when:
- The drawing has coloured shading (zoned floor plans where each zone has a tinted fill) and Stage 1 is picking up false matches inside the shading.
- The drawing has revision clouds in a specific colour that you don't want to count.
- A colour-coded layer has been left on the PDF and is interfering with symbol matching.
Ignoring a colour doesn't change the underlying PDF — it just changes the working image the detection pipeline sees.
For broad-stroke background suppression, use Remove Background instead — that targets large background regions without you having to pick specific colours.
Where the controls live
In Stage 2, open the Ignore Colours & Remove Background dropdown at the top of the sidebar's marker list toolbar.
Inside the dropdown:
- Remove Background — toggle covered separately.
- Ignore Colours — the section this article covers.
The section shows an Add button labelled "Pick colour group to ignore" and a list of currently-ignored colours. Empty state: "No Ignored Colours".
Adding a colour to ignore
- 1
Click the + button ("Pick colour group to ignore").
- 2
On the drawing, click on a pixel of the colour you want to ignore. ZeroCount samples the colour at that position.
- 3
The selected colour appears as a swatch in the Colour Groups list inside the dropdown.
- 4
The drawing's working image re-processes — the canvas re-renders with that colour suppressed.
You can ignore several colours — pick the + again and click another spot.
Removing an ignored colour
- 1
Hover the colour swatch in the Colour Groups list. A trash overlay appears.
- 2
Click the swatch. The tooltip reads "Click to remove colour group".
- 3
The colour comes back into the working image immediately. The canvas re-renders.
Workflow tips
- Sample from a clean area. When clicking to ignore a colour, click on a part of the drawing that's clearly just that colour — not on an edge where two colours meet.
- Apply before running Stage 1. Ignoring colours after detection has already run doesn't change the existing markers — it only affects future detection. Apply at the start, then Submit.
- Combine with Remove Background. If a drawing has both a coloured shading layer and a textured background, turn on Remove Background and add specific colours to Ignore Colours. They stack.
What about groups of similar colours?
Ignoring a single colour also catches near-matches — slight variations in tone count as the same group. If you find that doesn't catch everything (the drawing has gradients, or several distinct shades of a similar colour), use Ignore Colour Groups — see Ignore colour groups.