Gmail – How to mark some but not all emails in Gmail as read

There are two ways:

1. Perform a search to find all the messages you want to select. (You can use is:unread too)
2. Click select all
3. You will see that above the first item in the list there is a banner that says something like: All 50 conversations on this page are selected. Select all # conversations in "..."; click that link.

You can also do this with a filter, by creating the filter, choosing to mark the messages as read, and then choosing to apply the filter to the matching conversations. Then simply delete the filter.

You can't as of now. Sorry!

There is one option though .. Go in Google Labs (once you are logged in on Gmail) .. then enable Mark Unread From Here and try!!

Description of what it does .. *

Adds a new option to each individual message's drop-down menu that will set that message and all following messages as unread, so when you come back to the conversation later you can pick up reading where you left off. Click the button with the triangle icon in the corner of the specific message you want to start reading from later, then select "Mark unread from here"

*

Hope it helps.