Why do checkmarks appear in different colors?

[Accessibility UTA]

In Adobe Acrobat Pro, the checkmarks in check boxes appear black.  If the same file is opened in a browser (Sharepoint or Teams), the checkmarks appear as orange - which fails the minimum color contrast required by WCAG 2.1 AA.

How do I force the checkmarks to always appear as black, no matter how the document is viewed?

[MikelKlink]

PDF viewers, when showing form fields, can display them using a custom appearance. This custom appearance actually is not defined by the PDF specification but really custom, it is based on some hints in the PDF but not fully defined by them. Furthermore, PDF files can contain a complete appearance for each form field which the PDF viewers can also use.

What you observe, therefore, is a situation in which the appearances the different PDF viewers show differ greatly.

If you are lucky, the orange checkmark appearance is the appearance (or derived from appearance hints) from inside your PDF because in this case you can update your PDF to contain a good appearance (or good appearance hints).

If on the other hand it's the custom appearance generated by the viewer, it is not under your control but may depend on the viewer configuration.

Ah, if your files contain hybrid form definitions (AcroForm and XFA), that's another possible cause for your observation. Some viewers then display the form as described using AcroForm objects while others display it using the XFA XML data. And these form definitions may differ considerably.

As you did share an example PDF to illustrate the issue, I can just name some possible causes but I cannot tell you which it is in your case.

[Thom Parker]

I think what Mike means to say is that it should not happen. The appearance of those checks is explicitly defined in the PDF, which is what PDF is all about. By definition, a PDF file should look exactly the same in all viewers on all platforms.

If it is not displayed the same, then that viewer is non-compliant piece of crap and you should avoid using it.   

[Accessibility UTA]

My co-worker and I open the same PDF. The PDF was created originally in InDesign. When she opens the file, the checkmarks are black. When I open the file, the checkmarks are orange. We are both using Adobe Acrobat Pro. I have the same orange experience on Mac and Windows machines.

[Thom Parker]

Is the checkmark itself orange? or is the bacground of the checkbox orange?

If it is the check, then te checkmark you see is called the "Appearance", which, in this case is a vector graphic of the checkmark. There is also a set of parameters in the PDF that define how the vector graphic should be drawn. It is possible that InDesign created the checkmark Appearance one way, but didn't set the drawing parameters. In this case Acrobat may  recreate the Appearance. If it does, then it uses the (default) drawing parameters, which would result in a different appearance than the one created by InDesign.  I've seen a similar problem many times, many years ago. The InDesign team provided more appearances of form fields than were actually creatable through the form field drawing parameters. Whenever certain things change on the form field, Acrobat redraws the form field appearance. You have to think the InDesign team never actually tested this feature before releasing it.  

This of couse is speculation.  If you really want to know you'll need to prove a sample file and more specific information.