Question how to get 'Secondary Title of Painting' populated in Gravity Forms

please see http://www.peter-test3.co.uk/art-portfolio-item/brown-vase/ page. I am trying to get gravity forms to pre-populate the painting enquiry form. I have got the first field (title of painting) to populate by using {embed_post:post_title} in the gravity form. What i am trying to achieve is to also pre-populate the secondary title of the painting field with the text ” Brown vase with Flowers by Jill Bathorpe” . This is currently set using the Special Heading element but I need to know the description filed of where it is stored. i.e Where and how in the WordPress database is saved that text. Could you help me please.