The affordance of a door is that you can open it. You know it by your conceptual model of how works a door. But without signifier, you don't know where and how to open it. Affordance: is what a product/object can do. Signifier: perceivable cues are signs indicating what you can do.

1. Signifier: perceivable cues are signs
indicating what you can do
Affordance: is what a product/object can do
Note:
The perceivable part of an affordance is a signifier.
A "signifier" is, a sign that guide people to successfully interact with the design.
Signifiers are signals, communication devices.
These signs tell you about the possible actions; what to do, and where to do it
Handle (signifier)
1
This is a door.
The affordance of a door is that
you can open it.
You know it by your conceptual
model of how works a door.
But without signifier you don t
know where and how to open it
INTERACTION DESIGN
Massimo N. Marrazzo - 2017Frozen food Doors

2. INTERACTION DESIGN
Design should always disclosure the signifier
How can I open this door?
Is there an hidden handle or is it
an automatic door?What is wrong?
No signifier for these doors
Suggestion
Massimo N. Marrazzo - 2017Frozen food Doors
Handles or some colored sign
on the frame
2

3. INTERACTION DESIGN
The same supermarket decided to add classical handles
Good news
Massimo N. Marrazzo - 2017Frozen food Doors
Handles are glued
on the doors
3
March 2017 UPDATE
BEFORE
AFTER