How to Modify Header for Custom Title Tag with Image.php

In order to have customized image hosting attachment pages (WP’s internal gallery), I have created an image.php file and somewhat customized it, but am having troubles customizing header.php file to give image.php custom title tag (title that’s in the head of the page). I would like the title tag to display the title of an attached image, but am lost as to how to do it and search across the interweb has landed me with zero support. Can anyone help?