Blue and grey ticks question from non-iPhone user

[wd88]

Hi there.
I am an Android user and a bit puzzled with when the two ticks become blue and when they don't with messages I send to iPhone users in WhatsApp.
Let's take an example, I send a message to an iPhone user at 9am, the two grey ticks appear at 9.30am, the last seen status of that person doesn't show a new time, though, shows any time before 9am, next day I talk to that iPhone user and they know the content of that message and have obviously read it, but no blue ticks ever appeared. Another day at, say, 10.30am I send that same person a message, I see one grey tick appear, at 12am I see two blue ticks and the last seen status shows 12am as well. In both cases the iPhone user has read the message, but one time it shows two grey ticks, another two blue ones.
Now as far as I know, all sorts of messages pop up on the screen of iPhones even when locked, might it be that the ticks appear in grey when that message is seen on the screen, but the person doesn't access WhatsApp to view it, and the two blue ticks only appear when the person actually opens WhatsApp and the conversation with me?
Just curious.
Thanks,
wd88

 

[knighty2112]

The first grey tick is after you send the message. The next grey tick is when it has reached the recipients phone. These the both go blue when the message has been read by the recipient.

 

[knighty2112]

The first grey tick is after you send the message. The next grey tick is when it has reached the recipients phone. These then both go blue when the message has been read by the recipient.

Edited for mistake.

 

[wd88]

Thanks for the answer.
Thing is, one time the person had read the message (we talked about it, so he obviously had), but the ticks never went blue. What I'm looking to know is, do the two ticks appear in grey when the person reads the message on the screen, but not in the app, so that effectively the person has read the message, but never entered the app which is why the ticks don't go blue?

 

[knighty2112]

All I can say is that mostly it works like I described, but there can be glitches in it. I too get times when I know the other person has read it, but the ticks don't go blue until later on. Not sure why.