running words around
design education and visual communication
authored by chris m hughes

Intuitive Grids in Illustrator

Saturday, 18 September 2010

Swiss graphic designers Karl Gerstner and Joseph Müller-Brockmann formalised the use of modular grid layouts - consistent horizontal divisions from top to bottom in addition to vertical divisions from left to right. The overall aim was to create well-proportioned designs where the layout could be controlled to maximise legibility and cohesion.

Their work pioneered a new way of controlling the placement and cropping of images as well as the alignment and spacing options for text. Today, grids are the foundation of both print and web layout design.

InDesign and Illustrator
Many students are happy enough to use guides and grids for their layouts when they work in InDesign. InDesign is brilliant for spreads and multi-page documents, controlling columned type, and features powerful grid and guide tools.

But when it comes to Illustrator, it's very easy to have blocks of text, objects and images randomly floating around on the artboard, in a permanent state of 'nearly' being in the right position. All sorts of arbitrary decisions and tweaks are needed to move these elements into a 'good-looking' position during the final composition.

This is because Illustrator is more about experimentation. It doesn't support page spreads, but is better for stand-alone pieces (e.g. posters, packaging), and for creating original vector graphics (logos and complex type). With its multiple artboards and almost endless canvas space, Illustrator is like a huge digital workbench.

So students are somewhat mystified when we start encouraging them to use grids in Illustrator. The emphasis on precision seems counter to the looser creative processes the tool encourages. And they aren't keen on the maths involved.

But of course, they are already working within the constraints of the grid, they just don't realise it. Their intuitive decision-making about element placement is derived from simple laws which are found in nature, and which are hotwired into our visual senses. These laws are the Golden Ratio and the Rule of Thirds. Both laws are based on aesthetic proportions first documented in antiquity by the Egyptians and the Greeks.

The good news is that if we incorporate these laws into a grid, composition becomes easier to control, the decision process is simplified, and visual communication becomes more effective.

The downside is that creating a grid like this in Illustrator can be complicated, because Illustrator lacks some of the more user-friendly tools of InDesign, such as margin guides and the baseline grid.

Intuitive Grids
As a starting point, it's simple to create an 'intuitive' grid. It requires little or no maths - you can round up some of the more awkward measurements - and the result is a robust grid which can be customised for any stand-alone print solution. The grid is a mixture of three kinds of fundamental guides:

1. Margins
2. Baseline Grid
3. Rule of Thirds

In the following example, we are creating an A4 poster grid in Illustrator CS4.  Firstly we need to create a guide layer to on top of all the artwork.  Then create the margins on that layer.

A4 is 210mm by 297mm, so using the 6% rule, my side margins will be 12.6mm each, and the top/bottom will be 17.8.  To create this, draw a rectangle on the artboard and (1) align it to the artboard. Then (2) make the centre of the rectangle the reference point. Now (3) in the dimension measurements, just type in the minus values of each axis.

Setting Margins

Your rectangle will now reduce in size to the margin boundary of your artboard. No need to drag any guides.  You can convert this shape to guides if you wish, using view > guides > make.  But before you do, you may want to add the baseline grid.

Baseline Grid
A baseline grid allows you to align type (and images or shapes) so that regardless of size, you retain proportional spacings down the page. This is called 'vertical rhythm'.

This grid will use the smallest unit of type that will be in your design - 12pt is a typical standard value. The measurement is then twofold - the pointsize plus the leading. To create this, first right-click on your rulers and change the units from Millimetres to Points.

Ruler Units to Points

Next, select the rectangle and go Object > Path > Split Into Grid. The Split dialogue box appears. Note that the default gutter size is 12pt - this is our leading. Now just click on the row numbers until your pointsize is as close as possible to 12pt. In this example, at 32 rows it reaches 12.03. Edit that value to exactly 12.

Intuitive Row Count

Now go Object >  Group. The baseline grid is complete. Doubleclick the layer and convert it to a template. This locks the layer at 50% opacity.

Rule of Thirds
Regardless of page size, rule of thirds creates nicely proportioned modular units that also include the visual centre rule and (through further divisions) the golden proportion. It's a 3 X 3 grid, with four junctions or 'hotspots' where the visual power of a placed element is at its greatest.

Create a new layer and then go to the line tool. Expand the tool options - one of them is rectangular grid tool. Click once on the artboard and set the horizontal and vertical divisions to 2. You'll need a 0.5pt stroke with no fill. Now drag from the top lefthand corner of the artboard to create the 3 X 3 grid. Ignore the margins - we want this grid to encompass all of the printed page.

3 X 3 Grid

Finally, using the direct select tool, compensate (remember we rounded up the margin size and rounded down the pointsize) by nudging the central horizontal rule of thirds lines onto their closet baselines.


Once the grid is complete, you can test it. A good exercise is to simply place some lines of text in your layout. Make sure the pointsize and, more importantly, the leading are multiples of the 12pt unit. If you then set one line of text flush to any baseline, all the other lines sit flush to their corresponding baseline. This gives you perfect vertical rhythm on the page.

In this example, we have 72/60 in Old Sans Black (a freely available variation of Aksidenz Grotesk):

Baseline flushed

You can now experiment by adding further grid layers. For example, a 6 or 12 column grid will divide your rule of thirds up to create a flexible set of grid modules. You can include gutter sizes in the split option as well. Additional divisions will depend on the layout you have in mind - an intuitive call on behalf of the designer.

If your design features diagonal elements, two extra steps allow you to create a diagonal baseline grid:

1) Set the margin rectangle, then make a copy of it. Set the baseline grid into the copy, and then rotate it to the exact angle you plan to use. Drag the sides of the baseline grid out to cover the whole canvas. You should now have a margin guide, a rule of thirds guide, and your diagonal baseline grid.

2) Go to Preferences >  General and set the Constraint Angle to the value of your baseline grid. Now when you type on the page, or drawn any shape, it automatically displays at the angle your want. You can then place these elements flush to a baseline for perfect angled vertical rhythm.

Diagonal Grid

The Grid System
Complex Grids @ whattype
Thinking with Type/Grids