Image and style editing with G'MIC

Let's look at G'MIC, the open-source image processing toolkit!

I think we all benefit from a broad awareness of the powerful changes you can make with classic image processing tools like G'MIC. Nobody needs to resort to generative AI as their first port of call for graphical editing.

G'MIC is available as a plug-in for Affinity, Krita, Photoshop, GIMP, etc, or as a standalone tool. Its huge library of "filters" implement and combine classic image processing algorithms. You can get it at https://gmic.eu/gmic300/ 

I'm going to focus on the most drastic and completely transformative adjustments you can use G'MIC for, showing some of my favourite effects. I'll mostly skip the subtler filters as well as the tools that modern image processing programs usually have built in; suffice to say that G'MIC covers those too.

I'm going to use one input image throughout, to demonstrate various effects. I'll use the following collage that covers a bunch of areas: photographic, cartoon, lineart, discrete object, watercolour, stylisation, realism, areas of light and dark, areas of high and low contrast, hard and soft edges, etc.

Image credits: Fisktak (https://fisktak.itch.io). Publisher’s Choice Quality Stock Art © Rick Hershey / Publisher’s Choice Stock Art (https://patreon.com/StockArt). Adobe Stock.

This is going to be an image-heavy blogpost, as I showcase the outputs of tons of different G'MIC filters on this collage. In some cases, you'll see that a filter works better in one part of the image than in others.

In other cases, the filter will unify all parts of the collage into a single aesthetic. I'm particularly interested in that. When working with stock art and licensed art, it's very helpful to be able to take a bunch of disparate graphical elements from different artists, and adjust them to create a unified style. That confers a stronger sense of an overall project aesthetic and identity.

Combining G'MIC filters with consideration of palette, recurring motifs, proportion, and so on, means that you can pick out assets for a design and not care that they're variously a photo, a watercolour painting, and a vector graphic. You have the tools to translate them into a single visual style.

Let's look at some filters! 

Changing art style

You can use G'MIC to recreate an image as if with traditional media like pens or paintbrushes.

Marker drawing filter:

Sketch filter:

Brushify filter: 

Angoisse anguish filter: 

Changing style: Black & white

Some of G'MIC's filters imitate black-and-white traditional media. These can be quite striking.

Charcoal filter:

Engrave filter:

Lineart filter:

Pencil portrait filter:

Changing style: Flat areas 

There are lots more art styles G'MIC can mimic, including ones with large areas of colour.

Cartoon filter: 

Vector painting filter:

Comic book filter: 

Cubism ['Cubisme B'] filter:

 

Experimental lines

We can change an image's style even more dramatically by using G'MIC to redraw its lines in abstract ways.

Stringify filter:

Black crayon graffiti filter:

Filaments filter: 

Experimental colours

G'MIC also has lots of filters that dramatically change a picture's colours, for various high-contrast effects. The following three are from various contributors' experimental filters.

Frequency representation filter:

Neon filter: 

Hallucinogen filter:

 

Adding effects

We can use filters to overlay all sorts of visual effects on top of an image.

Bokeh filter:

Rain & snow filter:

Random waves filter:

 

Water drops ['drop water'] filter: 

 

Position in space 

There are hundreds of G'MIC filters that re-render the image in different spaces, or that warp its 2D shape in various ways. I've spent a lot of time just turning pictures into abstract art by fiddling with the 3D filters. Many of these could be useful for futuristic settings, backgrounds, and visualisations.

Loose photos filter: 

3D blocks filter: 

3D elevation filter (with Phong lighting): 

 

Glitch effects

There are some good glitch filters in G'MIC. Very useful for science fiction and futuristic edits. I won't show 'Self Glitching' here because it doesn't work as well with the collage but I love it: you can just pop an image in and hit randomise and you'll get something great within a few runs.

Huffman glitch filter:

Shredder filter:

Superstreak filter:

VHS filter:

 

Quantisation

G'MIC has lots of filters that create mosaics, partition or rearrange the image, find and reinforce edges, and so on. Here are some for making a picture into a grid of tiles or other pattern.

Smoothelate filter:

Tiled form filter:

Coloured ellipses ['Ellipses Colorees'] filter:

Hexagonal grid filter: 

Oldschool 8bits filter:

Ascii art filter: 

Weave filter:

Some of the mosaic effects are deeply transformative.

Squares lines ['Carres Lignes'] filter:

Little boxy things filter:

Mineral mosaic filter: 

 

 

Pack ellipses filter:

 

I should finally note that I haven't done G'MIC any favours by using a collage as input. The image has high variability across multiple axes, local clusters of complexity, etc, which really put the filters through their paces. As a result, sometimes an area of the image ends up with disproportionate 'attention'. In a few cases, part disappears completely.

Unless you're using G'MIC as the final stage in compositing, you'll almost certainly get a better result by dialling in some settings you like, then applying the filter to your images separately. To ensure consistency you can copy-paste settings from the plug-in, or process your images as a batch from the command line.

Where G'MIC really shines is when one of the filters is an exact match for the aesthetic of your project. For example, if you need to create a 90s VHS look, then you'll be putting the G'MIC VHS filter on every single image. Similarly for filters like ghost, Dorure Gilding, CRT phosphors, stained glass, oldschool 8bits, wiremap, old photograph, and so on.

Where it becomes really powerful is when you use masks and blend modes to combine the filtered image with the original image for more nuance. You can blend spatially into just the part of an image that should be affected, or blend selectively by value or hue, for some really interesting results. These are approaches I'm still experimenting with, and I think hold a lot of promise.

Tools beyond imagining

G'MIC has close to a thousand filters, including some entire categories I haven't mentioned! For example, you can use G'MIC to procedurally generate and render entirely new images.

Here are some I made by just plugging random values into the parameters of the Chirikov-Taylor, neon lightning, organic fibers, spline spirograph, and Hitomezashi stitching filters.

You can find G'MIC and instructions for using it at https://gmic.eu/gmic300/ .