Open rate is an important figure to show the performance of your campaign. Our system tracks the action by an invisible image. When recipients open the email with the image, the action is tracked . Unfortunately, the blank image might not be opened spontaneously due to security setting. Recipient would need to allow images to be displayed in order to have the open rate recorded.
Click rate of a campaign refers to the clicking of a link included in the email. Every click of recipient is recorded and that shows you how much attention the link gained from the target. The report could be found under Campaign.
Would there be NO open rate but click rate more than zero?
Yes, this case occurs when a recipient doesn't allow images displayed in email, therefore, the open is not recorded. The clicking of link would still be tracked and this leads to a zero open rate but valid click rate.