Hello, GIMP developers:
In January 2018, I conducted a user test on GIMP v2.8, as part of a
class project. User testing is the process of having representative
users from your user personas do a task designed by the interviewer.
The interviewer then records breakdowns, situations in which the
test participant is able to follow a sequence of steps toward the
final goal, but got stuck at some point, failing to complete the
task.
I wrote a lot in the original report, but that was not a good way
of communicating. In this email, I will summarize the report.
I interviewed 5 people. Two of them are part-time photographers who
have 60k+ followers on social media. The other three are STEM
students who occasionally edit images for class projects. I will
name them A, B, C, D, E, respectively.
Task: consider the photo of a paper cup stack. Select the cup stack
and turn it black-and-white. A rough selection is ok.
====================
Issue 1: sub-windows
====================
All test participants expressed their confusion regarding the
sub-windows in GIMP v2.8. One of them wondered if they belonged to
different programs. Despite this, all participants started doing the
task without changing the default window layout. At the end, I asked
each of them to find an existing option that “turns everything
into one window,” but nobody found it. Participant A looked into
the preferences dialog, did not find the option, and started
browsing all the menubar items. He even opened the “window”
menu, but did not recognize the option.
Does the user think of the right thing at the right time
(conceptual model)?
No. participant C does not understand the default window layout.
Yes. When instructed, participants want to adjust a program state
to accommodate their preferences.
Is the action visible?
Yes. You can see it in the “window” menu.
Does the user recognize the action, even if the label is on
screen?
No. All test participants fail to discover this action. They expect
this action to be in “preferences.”
Will the user understand the feedback?
Yes, I believe participants will know the action works as they
expect, but they prefer to have “single-window mode” activated
by default.
Analysis – why does the breakdown happen?
Quoting my textbook [1], default values:
- are the initial state of the program.
- are the best values, reflecting the most common use cases you
observe. (Users don’t need to change them.)
Many users don’t change them.
Being completely new to the software, participants did not change
the default values. Default values did not reflect their
expectation.
Propose a solution!
GIMP should be in single-window mode “by default.”
Quote your participants!
- “Don’t have two windows. Use one window for the whole
program.”
- “When you open the software, you want to focus on the software.
You don’t want to see gaps everywhere.”
================================
Issue 2: accepting invalid input
================================
When finding the pen tool, participants D and E first looked at the
brush and texture panel, though it is not required for the task. In
GIMP, it is important to define a selection before using the brush
and texture panel. The panel is active when a path is in the process
of being drawn. A participant interacted with the panel without a
well-defined region, but this action did not change anything in the
image, or change the property of the tool.
Does the user think of the right thing at the right time?
No. The panel lacks a clear title. The participant thinks the panel
is some kind of filter.
Does the user understand the feedback?
No. The panel shows an option is selected, but the option does not
make sense in the current mode. The user expects a grayed-out panel.
Analysis – why does the breakdown happen?
No signifier: the panel (or tab) lacks a title.
No constraint: GIMP accepts input that does not make sense in the
current mode.
Propose a solution!
Give each tab a visible title, in addition to the hover text. You
can say: brush, texture, gradient.
Gray out options that do not make sense in the current mode. When a
path is still being drawn, gray out the brush, texture and gradient
panels.
==================================
Issue 3: deviation from convention
==================================
* By convention, I mean the previous knowledge which the user has
acquired by using other similar software.
Participant D could not close the path to form an area. She clicked
on the first vertex, but the path did not close. She then dragged
the vertices, hoping to make them “stick” together, but the path
did not close. Getting stuck, she was given a hint to right-click.
Following the hint, she converted the path to a closed region.
Does the user think of the right thing at the right time?
Yes. She wants to turn a closed loop into a region.
Is the action visible?
Yes. The action to make a closed region is in the “tool
options.”
Does the user recognize the action, even if the label is on
screen?
No. The participant tried to close the region by double-clicking
and dragging the vertices, later got stuck and asked for a hint.
Does the user understand the feedback?
Yes.
Analysis – why does the breakdown happen?
The participant uses what she learned somewhere else. The action of
clicking on the first vertex, or bringing two vertices closer, can
be used to close a path in other programs, such as Inkscape and
Photoshop.
Propose a solution!
- Show a “four-side arrow” when the cursor hovers on a vertex.
- Leverage what the user has previously learned! Implement a
double-click handler that closes the loop, since dragging on an
existing vertex moves it.
- Make two vertices “stick” together when they are brought
close.
=================================
Issue 4: lacking error prevention
=================================
Participant A makes high-quality selection, but GIMP removes his
region when he clicks on tool to see what it says.
Propose a solution!
- When appropriate, show a confirmation dialog before deleting the
user’s selection.
- When another tool kicks in, delete the selection only after the
user clicks on the canvas with the tool.
Quote your participants!
(Pre-interview) “When I have 300 photos, I don’t have 300 hours
to edit them. I apply filters and move on. Sometimes I use
pre-recorded settings.”
==================================================
Issue 5: non-descriptive names and lack of presets
==================================================
Participant C cannot tell the difference between “invert” and
“value invert,” until he reads the tooltip text. He cannot
understand what “colorize” and “colorify” mean until he
opens the dialog.
“Colorize” controls the hue, saturation and brightness. He
could have achieve the black-and-white effect by turning down the
saturation, but he adjusted the hue first, and he was not satisfied
with the result. He expanded the dropdown for presets, but there
wasn’t any preset.
Propose a solution!
Rephrase the options. For value invert, how about “brightness
invert,” as said in the tooltip description.
Value invert ==> Brightness invert
Colorize ==> Hue, Saturation, Brightness
Colorify ==> Colored-glass
Don’t leave out the presets. You can start with making simple
presets, like “desaturate”.
==========
References
==========
[1] Ko, A. (n.d.). “How to design user interfaces”
