Update
You can find the latest Skype/Lync standards documents here:
https://technet.microsoft.com/en-us/office/dn788953
The Skype Hardware Certification Specifications version 5.0 recommends imatest for sharpness testing.
You can find us mentioned on pagees 23, 85, 86
For Acuity testing, Skype recommends our SFRplus test chart, 24X40″, 5X7, semi-gloss, black&white, 2-tone
For >1.5m depth of field testing, Skype recommends our SFRplus test chart, 40X60″, 5X7, semi-gloss, black&white, 2-tone
The skype certification test charts are available for purchase in the Imatest Store.