Why do my PDF colors look different in WebViewer?

If you load a PDF and the colors look different in WebViewer compared to other PDF viewers (e.g. low color saturation) this is because "color management" is disabled without the use of the full API.

You can pass fullAPI: true to the WebViewer constructor to fix this and the colors should appear accurate.

If you don't want to use the full API you can also try disabling overprint which may make the colors appear closer to other viewers.

const { documentViewer } = instance.Core;

documentViewer.addEventListener('documentLoaded', () => {
  const doc = documentViewer.getDocument();
  doc.setOverprintPreviewMode(instance.Core.OverprintPreviewMode.OFF);
});

A color management system (CMS) is used to produce accurate conversions between different color spaces (examples including CMYK and RGB) and ICC color profiles.

For many documents and users this level of accuracy is not necessary and color management can be disabled in order to reduce the performance costs of accurate color conversions.

That said, for customers in the prepress industry or when Overprint support is needed we recommend enabling color management to deliver the high color accuracy that would be required for such applications.