Web Profiles

Capture mode and timing

How much of the page is captured, how long the browser waits, and how many pixels each CSS pixel becomes. Several of these fields switch themselves off depending on the rest of the profile.

Viewport or full page

These settings are in the Capture behaviour section of the Web Profile form. Capture mode has two buttons:

ValueMeaning
View PortOnly what fits in the window — the part of the page a visitor sees before scrolling. Fast, small, and consistent in size. A new profile starts on it.
Full PageThe whole document, top to bottom. The browser scrolls through it and stitches the result, so the image is as tall as the page.

Full page is not always the better answer

A viewport capture of a home page is a comparable, fixed-size record you can flick through. A full-page capture of the same URL varies in height every time the page changes, which makes a sequence of them harder to scan and much larger to store.

Auto height

Grow to the full page height applies only to a desktop image profile in full-page mode, and it switches itself on when you choose Full Page. On, the capture grows to whatever the page needs. Off, you type the ceiling in the box beside the switch.

FieldTypeDefaultDescription
Grow to the full page heightSwitchOn for Full PageLet the capture grow to the page's own height.
Maximum heightRequiredNumber100000250 to 100,000 pixels. Required when the switch is off; the capture stops at this height however long the page is. WebP and JPG have their own encoder limits (16,383 and 65,500 pixels, divided by the device scale factor); the form tells you the exact ceiling.

Infinite scroll will happily fill 100,000 pixels

A feed that loads more content as it scrolls has no natural bottom. A ceiling keeps one runaway page from producing an enormous file every single run.

Timeouts and delays

FieldTypeDefaultDescription
Page timeout (ms)RequiredNumber30000How long the browser waits for the page to load before capturing what it has. Up to 60,000 ms.
Scrolling delay (ms)RequiredNumber2000How long to pause at each step while scrolling a full-page capture, giving lazy-loaded images time to appear. Up to 10,000 ms. Full page only.

These two fix most of the captures people report as “blank” or “half loaded”. A heavy page that needs longer than thirty seconds wants a bigger Page timeout. A page whose images appear as you scroll past them wants a bigger Scrolling delay.

Longer delays cost capture time, not capture volume

A slower profile does not use more of your plan. It does mean each run occupies the renderer for longer, which is worth knowing if you are capturing hundreds of pages on the same cadence.

Scale and zoom

FieldTypeDefaultDescription
Device scale factorRequiredNumber1.001.00 to 3.00, to two decimals. The retina multiplier: at 2.00 a 1920-wide window produces a 3840-wide image with the layout unchanged. Desktop image profiles only, and only at or below 2560 × 1440.
Zoom (%)RequiredNumber10050 to 100. Zooms the page out so more of it fits in the window. Desktop video profiles only.

Scale factor and resolution are not the same thing

Raising the resolution gives the page a bigger window, so the layout changes and more content fits. Raising the scale factor keeps the same window and renders it at higher density — the layout is identical, the image is simply sharper.

Why a field is greyed out

Four fields on this section switch themselves off, and the form says why underneath each one. In full:

ValueMeaning
Scrolling delayEnabled only when Capture mode is Full Page. There is nothing to scroll in a viewport capture.
Grow to the full page heightEnabled only for Desktop + Image + Full Page.
Device scale factorEnabled only for Desktop + Image, and only at or below 2560 × 1440. An emulated device brings its own pixel density.
Zoom (%)Enabled only for Desktop + Video.
  • Nothing is broken when a field is grey — it simply does not apply to the profile you are building.
  • Change the media type or the capture mode and the relevant fields come back.

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