# How to plot a matrix as an image (greyscale)

**URL:** <https://discourse.julialang.org/t/how-to-plot-a-matrix-as-an-image-greyscale/34147>\
**Category:** Visualization\
**Created:** [February 4, 2020, 6:26am UTC](https://discourse.julialang.org/t/how-to-plot-a-matrix-as-an-image-greyscale/34147 "2020-02-04T06:26:11Z")\
**Posts on this page:** 5\
**Page:** 1

<div class="post-metadata">

**Author:** ![Ujku\_KU](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/ujku_ku/32/13159_2.png) [@Ujku\_KU](https://discourse.julialang.org/u/Ujku_KU)\
**Post date:** [February 4, 2020, 6:26am UTC](https://discourse.julialang.org/t/how-to-plot-a-matrix-as-an-image-greyscale/34147/1 "2020-02-04T06:26:11Z")

</div>

Hi guys, my question is how to plot a matrix as an image in greyscale?

I saw the version with ‘Gadfly’ and worked for me but it was in bluescale.

Thank you very much in advance for your support.

Cheers.

Ergnoor

---

<div class="post-metadata">

**Author:** ![mkborregaard](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/mkborregaard/32/556_2.png) [@mkborregaard](https://discourse.julialang.org/u/mkborregaard)\
**Post date:** [February 4, 2020, 6:57am UTC](https://discourse.julialang.org/t/how-to-plot-a-matrix-as-an-image-greyscale/34147/2 "2020-02-04T06:57:51Z")

</div>

With Plots, e.g., you’d do

```julia
using Colors, Plots
plot(Gray.(mymatrix))

```

or

```julia
using Plots
heatmap(mymatrix, color = :greys) #which will also give you a color legend

```

Most plotting packages should do something similar

---

<div class="post-metadata">

**Author:** ![Ujku\_KU](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/ujku_ku/32/13159_2.png) [@Ujku\_KU](https://discourse.julialang.org/u/Ujku_KU)\
**Post date:** [February 4, 2020, 7:12am UTC](https://discourse.julialang.org/t/how-to-plot-a-matrix-as-an-image-greyscale/34147/3 "2020-02-04T07:12:01Z")

</div>

@mkborregaard Hi Michael and thank you very much. Cheers. Ergnoor

---

<div class="post-metadata">

**Author:** ![mbaz](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/mbaz/32/17295_2.png) [@mbaz](https://discourse.julialang.org/u/mbaz)\
**Post date:** [February 4, 2020, 7:57pm UTC](https://discourse.julialang.org/t/how-to-plot-a-matrix-as-an-image-greyscale/34147/4 "2020-02-04T19:57:59Z")

</div>

Just for completeness… in [Gaston](https://github.com/mbaz/Gaston.jl) you can do:

```julia
using Gaston
M = [1 2 3 ; 3 2 1; 4 8 2];
set(palette="gray")
imagesc(M)
```

---

<div class="post-metadata">

**Author:** ![e3c6](https://avatars.discourse-cdn.com/v4/letter/e/e79b87/32.png) [@e3c6](https://discourse.julialang.org/u/e3c6)\
**Post date:** [September 2, 2021, 12:21pm UTC](https://discourse.julialang.org/t/how-to-plot-a-matrix-as-an-image-greyscale/34147/5 "2021-09-02T12:21:05Z")

</div>

Here you assume that `mymatrix` has values between 0 and 1?