How to reduce EPS file size

27. November 2009, 01:47 Illustrator

Sometimes it happens to everyone – you create a really cool vector illustration and want it to submit and sell on microstock, but you found, that the exported EPS file is too big. What can you do, to make the EPS file smaller? Here you will find several tips and tricks for reducing the EPS file size.

Sell it as bitmap

Well this is not the right answer (there are better in this article), but sometimes there is no another option. If your illustration is too complicated and uses transparency and special effects (blur, shadows, blending modes) and you don't want to simplify it, you can only generate big JPG version and sell it in bitmap format for example on Shutterstock, Dreamstime, Fotolia (read more about selling graphics on microstock sites).

Make it more simple

The main reasons, why the EPS files are so big are:

• using transparency or blending modes (overlay, screen,…) with gradients
• too complicated objects (traced objects from photos, etc)
• raster images in illustration

If you use transparency on gradients, just remove the gradients or the transparency and the size should be much smaller.

Sometimes the illustration contains a lot of small overlapping objects with same color – like the blades of grass, snowflakes on the ground and others. The solution is merging of such shapes into one shape (use the first Shape Mode in Pathfinder palette). Here is my example, how I save several kilobytes on the snowflake illustration.

The snowflake has a simple shape with complicated brush. So first of all, I just expanded the brush and then I joined all the objects. You can see it on the image:

1. Original snowflake
2. Stroke is expanded
3. All objects merged into one

There is also a tool for simplifying paths – just select the object, that you want simplify and use Object / Path / Simplify…. You should check the Preview option in the dialog, to see the updated version of the object and also to see how many points you will remove.

You can check the result on my snowflake here (and try to find all 2487 differences):

This tool just tries to remove some unnecessary points and try to simplify the illustration. You should check the updated version and compare to original version to see, if the illustration is still usable, if it doesn't lost important details.

Here are file sizes of the EPS file in each step:

Action	EPS file size	Difference
Original version	498 kB	0 kB
Expanded stroke	486 kB	12 kB
Merge	349 kB	137 kB
Path simplify	287 kB	62 kB
Total saved		211 kB

So we saved 211 kB on this one snowflake! And now imagine, if there is 20 such snowflakes on the illustration!

Delete unused palette items

In the EPS file, which was exported from Adobe Illustrator, is a lot of unused rubbish – for example all items from your brushes, symbols, graphic styles and swatches palettes. If you want to save some space, just remove the unused items from those palettes and save around 383 kB!

If you want to remove unused items just from one palette, display the palette (for example brushes) – use menu item Window/Brushes or keybord shortcut F5. Click with left mouse button on small arrow in upper right corner, which will display small menu, where you select Select All Unused item.

This will select all items from the palette, that weren't use in the illustration. Now just click on the small bin icon in the bottom right corner of the palette (or drag and drop selected items to this icon).

If you want to delete all unused items from all palettes, you can use special action for it. Display the Actions palette (menu item Window/Actions) and there select and run action called Delete Unused Panel Items.

How much space you will save? We can check it on this simple illustration:

Here are the results:

Operation	File size	Difference
Original EPS file	661 kB	0 kB
Brush palette clean out	500 kB	161 kB
Symbols clean out	500 kB	0 kB
Graphic Styles clean out	389 kB	111 kB
Swatches clean out	278 kB	111 kB
Total saved		383 kB

So you can save around 383 kB on each illustration – it doesn't depend on the original illustration size, complexity and your illustration didn't lost any details!

Scaling the illustration

It sounds a bit weird, but scaling vector illustration can make the final EPS file smaller! Vector graphic is made from geometrical primitives such as points, lines, curves, and shapes or polygon(s), which are all based on mathematical equations (definition from Wikipedia). EPS file is a normal text file, where all the information are saved – if you open it with some text editor (like Notepad in Windows), you will see commands for drawing lines and points + a lot of coordinates. And with scaling the image you can save some data in coordinates – instead of the coordinate 1254.1234 you can have just 85.5467, which will save you 2 bytes.

Small example from the part of the EPS file:

/BBAccumRotation (0.099254) XT
353.0381 585.3188 m
359.7197 542.3628 342.5811 534.6782 V
361.3486 541.8042 356.7959 584.6499 356.877 585.5068 c
356.9561 586.3647 353.0381 585.3188 y

The same part after scaling:

/BBAccumRotation (0.099254) XT
18.8721 197.2852 m
22.0313 176.9746 13.9277 173.3408 V
22.8018 176.71 20.6494 196.9688 20.6875 197.373 c
20.7246 197.7793 18.8721 197.2852 y

Saving on this short part of EPS file is 10 characters (10 bytes). Saving on the whole sample illustration was 15 kB (it is too simple illustration, to save more space). Here is the example illustration before and after scaling:

All parts of the illustration should be in the positive part of the art board (otherwise the minus sign will occupy one byte for each coordinate).

Raster image in vector

Sometimes is your illustration too big and you can't find the reason. Maybe you just forgot some bitmap image there – sometimes I use photo as a template and later, when I don't need it, I just hide or lock the layer. At the end of the work I forgot it there and then I'm surprised how big the final EPS file is. Here is simple procedure, how to find and select all raster graphics in your vector illustration:

1. Unlock all objects – Object / Unlock All or Ctrl+Alt+2
2. Show all hidden objects – Object / Show All or Ctrl+Alt+3
3. Select all raster objects – Select / Object / Raster Art – you must have Select Menu plugin installed to have such option in your Illustrator (or some newer versions of Adobe Illustrator have it already).

Other possibilities

Some people recommends to import illustration into Corel Draw or Inkscape and save it as EPS – such files are much smaller (I don't have any of those two applications, so I didn't try it).

Some other tips (mostly about saving in the EPS format) were mentioned in the article How to prepare vector illustration for microstock sale.

Do you know about any other way, how to make the EPS files smaller?