Illustrator Crash Course

If you haven't seen this already, check it out. Four weeks worth of lessons will introduce you to the tools & basic tricks of Adobe Illustrator CS3.

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Letterpress Step 2: Prepping Files for Photopolymer Plates

In the first post of this series we turned a regular photo into a two-color computer illustration. For the next step, we need to get this image ready for printmaking. For those of you familiar with prepping files for offset printing some parts of this process will come naturally and others will be counterintuitive.

Most of today's letterpress printing of images/illustrations is done using photopolymer plates. Photopolymer plates are light sensitive plates onto which light "burns" a negative of your desired image. The area that light touches remains raised and the rest is washed away, leaving you with a surface akin to linoleum or wood carvings (in the sense that the raised part represents a flipped image). I'll talk about the process of making plates a little in my next post.

I think it's safe to say that most letterpress printers do not have access to plate-making equipment, but rather order their plates. One of the most notable photopolymer plate-makers is Boxcar Press here in New York state. Other businesses who offer letterpress parts & supplies sometimes process plates as well, like NA Graphics in Colorado.

Let's get our illustrations ready for new plates!





Step 1: When deciding on an illustration to use for letterpress, you need to make sure that it fits the limitations that letterpress presents. If you are designing your first project for letterpress, take a look at Boxcar Press' "Seven Easy Steps to Photopolymer Perfection" for some tips. I've outlined a few of their more general tips above.

The major reason that letterpress printers ask you to use Pantone colors is because letterpress printing doesn't work in the way that offset printing does – a 4-color [layered] process using CMYK cannot be applied the same way. Pantone inks used in offset printing can also be used for letterpress printing, so custom printers will have them on hand. They can often find your ink color on their shelves or get it mixed for you. An unspecified color would have to be matched to a Pantone color or in some cases, hand-mixed. Each different color, even different screens of Pantone colors that you would consider a single color in offset printing, are a unique pass through the letterpress. This leads us to the next step...




Step 2: Looking at my illustration of the holly, I have two distinct colors Pantone 1805 (the red) and Pantone 4625 (the brown). If I had originally had more colors than this, this could have been the time to simplify the illustration. An example of simplification could be changing Pantone screens into 100% color or white to eliminate the need for more colors. Each distinct color requires its own photopolmer plate & a unique pass through the letterpress, so the fewer colors the better.

Getting the files ready for making plates takes a little bit of pre-press work. In off-set printing many of the following decisions are made for you by the printer's pre-press department, but when you're making plates you need to decide how to treat your files. Registration (or the alignment of multiple colors) is tough in letterpress & takes a lot of time to get right. That's why you'll see many designs that avoid perfect registration by not having objects overlapping or intersecting. I designed this illustration early on and hadn't considered the difficulty of printing it.

The following are some pre-press methods for separating your colors....


Knockout: Knockout creates a white hole underneath the object on top. This way colors that appear to the eye to be overlapping are both being printed directly on the paper rather than one on top of the other, each showing its truest possible color.



Knockout Problems: The problem with knockout is that it doesn't give you any margin of error in registration. If registration is the slightest bit off then white space will show up between the two objects that are supposed to appear to be overlapping. This problem was inescapable for me with the Christmas cards since I chose this method of preparation. In the end, I really enjoyed the off-kilter effect, but that's not to say you will in your work.



Overprint: Overprinting can create some really cool effects in letterpress (which I look forward to exploring myself in the future), although it's not always fun if you don't mean for it to happen. Rather than creating a white space beneath the top object, overprinting does exactly what it sounds like it'd do: one pass of ink goes right over the other. Click on the picture above for more detail and you'll see the darkened areas that result on the berries because of the red ink combining with the brown ink.


Trapping: Trapping can sometimes combine the best of both worlds by creating a margin of error for the knockout method. By slightly increasing the size of the object on top, it is able to move slightly from perfect registration without exposing any white below. At the same time, you'll have a tiny bit of overprint effect on the edges where the colors overlap (overprinting is exaggerated above for visibility).


Step 3: For my image, I've decided this time to overprint the brown ends on the berry and use trapping to make sure branches & berries meet. Step 3 involves separating the two colors. What I do is draw an outlining box or create crop marks to remind myself later how the two images align (this can be very important when trying to get things lined up on the press). Sometimes it's even required by plate-makers or letterpress printers who'll be using your custom artwork for printing.

Once you have an outline around the whole image you can copy & paste so you have two identical images. I chose one image to represent the plate that will have the brown ink, so I convert all the red berries in that image to white. Then I did the opposite with the "red plate" image. Now I have two images that represent the two plates I'll need to "reassemble" for the final letterpress product.


Step 4: Aside from the color separations & initial considerations for your image, getting your files to your printer or plate-maker doesn't differ greatly from what you need to do for offset printing. Each printer may ask for different things, but I've put a few common requests above. If you're a letterpress printer looking to make plates for home, or if you're just curious about the process, check out Boxcar Press' tips on preparing your files (including an elaboration of some of the tips in Step 1) or their pricing & turnaround info here.

If anything needs clarification or correction, please let me know!

Letterpress Step 1: Make an illustration from your favorite photo

For me, the first step to a new letterpress card is the illustration. I keep an "idea notebook" of sketches, and most of my illustration is done by scanning sketches & tweaking on the computer, or by using my photographs as the basis for a new design. Over the course of several posts, I'll be showing you all the steps from idea to final product for the latter.

Along the way I'll include some links to similar tutorials & tips that I've found very helpful as I've learned how to use the computer to draw. Some of the tutorials use Adobe Photoshop and others use Adobe Illustrator. I am more familiar with using Illustrator, so that will be my reference here.




Step 1: The first step is to select a photo that you find visually interesting. It's good to remember that not all great photos make great illustrations and some truly mediocre photos make perfect illustrations – the more you use photos to draw, the better feeling you'll get for it. In general you want to look for a photo that is simple with high contrast. I also try to choose one that presents an iconic view of the subject; a photo that is straight-on or more shallow in it's depth will be easier to convert and the final result will be easily recognizable. In letterpress, each unique color is a separate run through the press so I try to use as few colors as possible.

My love of photography is what segued into design & now letterpress, so I have a stockpile of photos. This particular photo is of deciduous holly growing in central Minnesota. It wasn't taken with such a great lens, so you'll see some chromatic aberrations. The great thing about converting to an illustration is that those kind of flaws disappear. If you can't find any photos in your own library there are public domain photos & illustrations you can find on the internet and some really great ones you can buy at sites like iStockPhoto.



Step 2: This step is pretty straight forward and incorporates the same tips from Step 1. You don't necessarily want to use the entire picture, so choose the best part. Crop your photo according to your taste and save a copy in an easy to find place on your computer.



Step 3 (click for more detail): In this step it's time to bring your photo into your illustration program, in my case Adobe Illustrator. Create a new layer for your tracing or lock the photo onto the art board; you don't want it moving around during the process. Make sure to keep saving throughout the process, I've had more than one illustration eaten by my computer.

For the tracing process I always choose a bright colored line with no fill. This way I can see what I've done and not miss any of the remaining details. Mentally break up your image into smaller manageable parts. In this case, I'll do each berry separately, the brown end of each berry separately, and the branch in several pieces.

Since I am using my computer's mouse as my drawing tool, the Illustrator pen tool (circled above) makes the most sense. The automatic Bezier curves (see in action above) also help keep things looking natural and not ragged. To utilize the Bezier curves, click your first point and then click a second. On the second point do not release your finger while moving your mouse a little away from the point. You'll see the curve appear. Move your mouse around to get it just right. The next point you make will take lead from this curve, hopefully helping to create a natural line. If you don't want the next point to follow it's lead click once on the point before proceeding (you'll see the control handle & tangent/directional line disappear on the active side). Keep making points until you are able to close the object (meaning last point & first point meet) – this is very important if you want to fill your object with color later on.

This type of illustration took me a while to get used to, so don't be disheartened by your first attempts. Try as much as possible to use the Bezier curves to your advantage – they can really help your drawing look natural. Single points strung together without any curves can end up looking jagged; this was my issue when I started drawing this way.

Depending on your level of expertise, here are a few good tutorials to get going in vector illustration, with more details & tips than I've provided here:

Mike's Sketchpad: The Anatomy of a Vector Illustration
This tutorial is perfect for beginners & intermediate illustrators using different programs. Mike takes the time to introduce all the tools & definitions for you in a very digestible way.

Lemontea: Definitive Vector Guide
Beginner/intermediate with a focus on Photoshop.

Adobe Illustrator Techniques: Imitating a Scanner Darkly
Advanced Adobe Illustrator tutorial for converting a photo into a piece of art, in the style of the movies A Scanner Darkly and Waking Life.

Melissa Clifton: Turn Photos of People into Line Art
Melissa has a lot of great tutorials, but I'm especially impressed with this advanced Photoshop tutorial. I frequented her site when I was just getting started. Even though her focus is on Photoshop, many of the ideas can be transfered to Illustrator.

Please feel free to add other pertinent links to the comments section.



Step 4: This last step is a lot of fun because you get to see everything come together. Click on any finished shape (or multiple shapes that need to be the same color) and choose a new color for line & fill. You can even use the eyedropper tool to pick up a color from your original photograph.

Making sure everything is layered correctly can be tricky. This is why illustrators dealing with complicated images will use multiple layers in the beginning to separate out bottom, mid & top layers & even different colors. If you did everything in one layer, just select objects and move them as needed. For example, I would select one of the brown seed ends and go to Object menu>Arrange>Bring to Front so it's on the very top where it can be seen. Check out the short cuts in the Arrange menu and it'll make it a lot faster.



Step 5: This step may not be necessary. I like to simplify certain aspects (like the bumpy, out-of-place berry) or in my recent asparagus illustration I actually stretched the asparagus to be wider. Follow your artistic instincts.



Step 6: Now your image is ready to be used for design projects you may have. Above is one of the roughs for the Christmas card (slightly scaled) that my husband & I used last year. The other is a business card, just as an example. Notice that I decided to rotate the branch for these uses.

Getting this image ready for use in letterpress is another step that I'll go through in a another post very soon. Do let me know if you have any questions! :-)

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As a last note, here are a couple of other transformations from photo to illustration that I've done. The first is of my cat, Ushi. The second is of asparagus I expressly bought from the store for this purpose. I put the asparagus on a sheet of lined paper and quickly snapped the picture without much concern for lighting, but I'm quite happy with the final product. Enjoy, and happy drawing! :-)