While I don't know what baseline you're comparing it to, 12% does not seem like a high open rate.
In my experience, cold sales emails should hover around 20-30%, so opted-in lists should at least perform on par with that.
Exceptional newsletters like The Hustle average ~50% opens (with over one million subscribers).
Also, you have to be careful with your image to text ratio.
Excessive images are often not helpful for deliverability as spammers have historically tried to embed images with spam text (where it's more difficult for the ESP to parse) versus actually including it as body text.
Comments
While I don't know what baseline you're comparing it to, 12% does not seem like a high open rate.
In my experience, cold sales emails should hover around 20-30%, so opted-in lists should at least perform on par with that.
Exceptional newsletters like The Hustle average ~50% opens (with over one million subscribers).
Also, you have to be careful with your image to text ratio.
Excessive images are often not helpful for deliverability as spammers have historically tried to embed images with spam text (where it's more difficult for the ESP to parse) versus actually including it as body text.