How to add noise to a drawing (and why to do it)

How to add noise to a drawing

Leggi in italiano

In this post I will explain a simple way to make your drawings less flat and avoid the “cartoon” effect that in my opinion is not good for any style. For example, in my cartoon-style portraits, which are not too realistic but not too stylized, I always add a “noise” level to avoid too homogeneous areas. But what does it mean? How you do it? And is it always necessary? Continue reading to get answers to these questions.
When I was a child I liked to paint my designs perfectly evenly. And I felt frustrated when I could not. Teachers, on the other hand, seem to have the mission of teaching children to color without ever changing direction and leaving no white space, as well as remaining in the margins (habit that returns useful when learning to write). A simple and effective way to nip in the bust any artistic ability. At a late age I found that in many cases the uniform layer of color, which is very easy to get with digital tools, is not always pleasing to the eye. Or rather, sometimes add some grain effect, also known as noise, improves the drawing. If you think about it for the same reason that old photographs, especially if in black and white, have some charm. In short, the classic “film effect” is normally pleasing.
That is why I decided to explain the process I follow to borrow a similar effect on my drawings.
Note: for simplicity I refer to Photoshop CS3 commands, but you can easily find by yourself the homologues GIMP, Krita or other graphics programs.
Find in the following the step-by-step procedure.

1. Create a new gray level

The first step is to select the subject’s shape, create a new layer, rename it appropriately (e.g. “noise”) and fill it with a medium gray. Using a gray color means that the RGB values – ​​visible when you click on the color palette – are all the same. Since these values ​​can vary from 0 to 255, a good choice is setting Red = Green = Blue = 128. It is important that you use gray because in this way you will not change the color of the underlying levels, but you will only change the brightness. To fill in the selection with the foreground color, in Photoshop just press CTRL+BACKSPACE buttons.
Here is the shape of my Prince drawing I used as an example in the tutorial Lineart extraction made simple:
Sagoma grigia disegno di Prince.

2. Add noise

Selecting Filter->Noise->Add noise… you can add the actual noise. Choose an uniform or Gaussian distribution and adjust with the help of the preview to get the desired level. You will get something like this:
Sagoma di un disegno con rumore aggiunto

3. Blur the noise

Now you have to blur the noise you just added to make it more natural. To do this, select Filter-> Blur->Gaussian Blur and, as before, adjust the intensity as you prefer, but always cum grano salis (= with common sense)
Here is the result:
Sagoma di un disegno digitale con rumore aggiunto blurrato.

4. Change the noise layer blending method

The noise layer is below the lineart and above all others layers.
Change the blending method from “normal” to “overlay” (sorry, no traslation from italian menu in the picture).

cambio metodo di fusione livello da "normale" a "sovrapponi"

5. Adjust opacity

The last step is to decrease the opacity value of the noise level, for example 70%, or whatever the value you are most comfortable with, and…that’s it! Here is a detail that shows the final result.

Dettaglio disegno di Prince con e senza rumore aggiunto. Prince drawing with & without added noise.

The drawingis now less flat. You can also tune the effect making it stronger into some areas of the image, for example where there is skin, and lighter in others, for example on clothing, or vice versa.
Photoshop, like all graphics programs, offers many other possibilities for this kind of effect, from ad hoc brushes to grain filter. If you are curious about learning other similar techniques you only have to spend some time with Google, who in these cases is always your best friend.


Adding noise to a digital drawing is quick and easy. Doing this allows you to make the drawing more interesting and realistic , especially if it represents a person. I prefer to draw pseudo-portraits, so I add noise, especially on the skin, to make the effect of porosity. This trick also allows to give the “fabric” effect to the clothes.

In the case of less detailed drawings with fine lines and few shades, it is usually better to use a uniform color, but there are no rigid rules.

Well, I hope these tips will be useful for you.

Stay tuned!

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