How to get items of a selected type using get_records()

I'm struggling over an hour with the following problem:

I need to display items, that have a specified Item Type ('Picture') and have specified text (let's say 'mytext') in the field 'Creator'. I'm using the following code:

$items = get_records('item', array( 'advanced' => array( array('element_id' => 'Creator', 'type' => 'is exactly', 'terms' => 'mytext' )) , 'type' => 'Picture' ));

This returns nothing (the items with the conditions above exist in my archive - I checked id with advanced search form).
I tried different condition types but only 'type' => 'does not contain' returns results (but not the desired ones).

What am I doing wrong?
Is there any documentation for the get_records() function parameters?


You mentioned it but I'm not totally clear: Does an advanced search with the conditions you specify work?

In general, get_records for Items and the item advanced search will return identical results because they use the same filters.

Yes, the advanced search works with the conditions.

When I modify the code, putting ... array('element_id' => 39, 'type'... it returns results properly.
Is it possible to use the metadata field name directly?