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/ .

Graphic design again: Three book reviews

Today I report on three recent graphic design books. I'll be covering a great modern theory book, a collection of found typography, and a portfolio of New Zealand batik artwork.

Book 1:

Universal principles of design (third edition). 2023. William Lidwell, Kritina Holden, and Jill Butler

This book lays out 200 principles of design, encyclopedia-style.

Text 

This was one of the best books I read this year. The writing has an exceptional clarity at the sentence level and in its flow from one proposition to the next. Much of it is quite idea-dense and abstract, necessitating reading slowly to absorb the text.

The authors phrase things precisely and confidently. "Sound design is not the exclusive purview of a talented few" (Introduction). They expect an educated reader. "They are combined here because they are invariably combined in practice." (#151, Prototyping) If the writing has a fault, it's the occasional American-specific sports metaphor.

This is one of the only design books I've read that's not riddled with typos! Where most of the books I've been reviewing have errors on every page, I noticed just four across 400 pages, to wit: "shouild" in #107 (Legibility); "crticial" and "four-steps" in #142 (Poka-Yoke); "i.e." for "e.g." (#156, Redundancy).

Book design 

Universal principles of design is very professionally put together. The consistency of the layout lends it power, and each section is furnished with see-alsos, references, and links. There are two tables of contents with different orderings, and an index. I've died and gone to book design heaven.

If I have any complaint it's that the text is somewhat small, near the border of legibility. A typography example suggests it may be Trade Gothic set at 9 pt.

Content

The book covers 200 high-level design principles across many domains. Each concept is given with visual examples to discuss. These are elegant and minimalist, with a slight bias towards aerospace examples (one author is a NASA "human factors guru").

Some of the principles are interestingly specific, e.g., #093 (Icarus Matrix), which I could find very little outside information about, and #111 (Magic Triangle), which only applies to Muppet design(!)

I'm not a fan of changing the meanings of existing terms. #128 (Ockham's Razor) presents a concept in the design space which is analogous to, but different from, the established meaning of "Ockham's razor". Conversely, Clarke's Laws are given as a design principle, where they would have benefitted from being rephrased in a more design-specific way.

There is necessarily some overlap in the principles. The sentiment "not everything that can be counted counts, and not everything that counts can be counted" might appear half a dozen times in support of as many different-but-related concepts.

The authors have strong opinions and an evidence-based lean (although I could have done without the occasional flimsy evo-psych). They discuss how the foundational priming experiments (#144, Priming) mostly failed to replicate (albeit springing that disclaimer only after giving lots of details about it in the visual example).

They also pour cold water on the Golden Ratio and the rule of thirds, which "plays, at best, a minor role in creating aesthetic compositions but a valuable role in focusing attention." (#160, Rule of Thirds) I found the guidance useful enough to write it down:

1. If there is a strong primary element, centre it. Don't use the Rule of Thirds.

2. If there are two strong elements, balance them: position them at (especially diagonally) opposing intersections with the Rule of Thirds.

3. When there is a strong vertical or horizontal element, align it along one of the grid lines of the Rule of Thirds.

4. When there are many elements with similar visual weight, don't use the Rule of Thirds. 

I particularly enjoyed learning about Conway's Law (#040), Inverted Pyramid (#099), Poka-Yoke (#142), Visuospatial Resonance (#193), and some of the more philosophical discussion in e.g. Causal Reductionism (#023) and Root Cause (#158). The use of the Vasa warship to illustrate Feature Creep (#063) was very funny.

I'm reading design books this year because of my renewed interest in visual design, making the sections on Consistency (#035), Figure-Ground (#067), Highlighting (#091), and the von Restorff Effect (#194) interesting too. 

In summary

Universal principles of design is an absolute delight. The first time in a while that I'd like to own a shiny new copy of a book.

 

Book 2:

Look & see. 2018. Anthony Burrill

In this book, Burrill curates some of his collection of typography examples. These are reproduced reduced to black and white, with resulting grunge/distress effects. The typography is always black, never inverted or coloured, but there is simple, tasteful use of overprinted block colours for contrast.

 

 

Burrill has selected the "found typography" both for its characteristics and for its interesting provenances, which are described. The writing is somewhat amateurish, with its share of errors. It's somewhere in the triangle of poetic, banal, and twee, which I found made for a very easy read. I think it succeeds as a coffee table book, and could serve as inspiration for someone working closely with type.

The book's layout uses a fascinatingly wide typeface for body text, and is prolific with its arrows in a multiplicity of styles. Sometimes these design books have quite experimental features and I wish they'd explain them as they went!

 

In summary

Look & see is a fairly lightweight and relaxing read. I got a few ideas and laughed at a few curiosities, which is probably what you hope for out of a book like this.

Book 3:

 

An eccentric history in batik. 2025. Dinah Priestley

This new 242-page book showcases the art of Dinah Priestley and the late Tony Burton.

The text

After a rather stuffy guest foreword, the book is quite approachable.

Priestley describes her experiences with batik (traditional patterned dyeing using wax resist), as well as offering a sort of biography of her artistic life with Burton. I found myself wanting more details on the batik side.

A lot of Priestley's and Burton's art depicts parts of New Zealand history from older times into the early 21st Century, covering for example the Land Wars. With Priestley explaining the artworks, the textual content ends up comprising a mostly-unflinching look at New Zealand history.

Priestley's writing is rough and ready, but not bad. The authorial tone does sometimes dip into a sort of prim self-righteousness, e.g., trying to recast being a bad speller into an unalloyed good. But it's vivid and easy to follow. There are a few grammatical mistakes that unfortunately jump out at the most serious points (e.g., 'burnt alive' for 'burned alive').

Art

I wasn't familiar with Priestley or Burton, and enjoyed seeing their work. This book showcases hundreds of pieces, almost all in batik, but supplemented with cartoons and masks.

The art itself is wonderful. The unusual style of the artists, reminiscent of children's book illustrations newspaper cartoons and old woodcuts, is really set off by the choice of medium.

18th Century French Explorers Collecting Fauna

Annie Burnell Beauchamp

The fabulous Sir Edmund Halley 1986

1980s Wellington Stock Exchange

Layout

The book's chapters are casual, and their structure not too ordered: 'Blokes', 'Nightclubs', 'Sporty Types', 'Mistresses', etc. 'Blokes' comprises "fathers, gardeners, musicians, poets, wharfies, artists, kayak instructors, cricketers" and has the distinctive quirk of listing the ethnicity of almost every portrait subject, perhaps because the writer is from a certain time.

I liked the visual formatting. The book is laid out on a simple grid but doesn't keep to it strictly, as the batiks come in a variety of shapes and sizes (and the designer tries to set many of them to full pages). I notice that two minor variations of the 'Nikau and the Botanists' artwork are shown on pages 54 and 159, likely by mistake.

In summary

I read too few New Zealand books. I picked up An eccentric history in batik on a whim and Priestley's distinctive style really sold me. It's a visual treat.