In this tutorial I'd like to share with you how to use Adobe Illustrator to complete a design for the particular purpose of being printed on a piece of clothing. I'll be sharing tips and tricks I've learned during my time designing for apparel and using simple techniques in Illustrator to achieve this - nothing complicated!
1. Draw Your Design
Begin by roughly sketching out what you want to include in your design, it's okay to add details in at this stage, the more you have finalized the better! It just means less time deliberating what to include and what not to later in Illustrator. Try not to spend too much time on it however, especially if you have a deadline to keep! I personally use either pencil or fine liner pen - your preference really! When sketching out ideas it is also important to keep in mind that this is for a t-shirt, don't get too complicated. Keep asking yourself "would I wear this?".
2. Scan Your Illustration
Having completed your sketch, we're now going to scan it into the computer. It's important to always scan in at a high quality - I would usually recommend choosing the Black & White setting on your scanner (assuming it has this option, some scanners are different) along with a resolution of around 600 dpi, but no less than 300 dpi. These settings will ensure the quality of your scan.
3. Vector Your T-Shirt Design
With scanning out of the way, I'm going to create a new file in Illustrator (File > New) and we're going to use the settings shown in the picture. The most important setting here is the CMYK color setting. CMYK ensures that you can take your design to print later with no problems.
We are now going to place our scan onto the canvas by going to File > Place. Position it to your liking on the canvas.
Create New Layer above your scan layer called "lines" by using the button highlighted in the image. Then Lock the scan layer, making sure you don't move it around or, in later steps accidentally draw shapes on your scan rather than your "lines" layer.
Before we start drawing over our scan it's important to set up your Calligraphic Brush Options first. For my illustration I used these brush settings shown in the picture by selecting the Paintbrush Tool (B). It helps a great deal here if you own a graphics tablet - it's something that in this line of work is a very necessary and a worthwhile investment. If you do own a tablet the pressure setting will help a great deal when you are drawing lines and will give you a lot more control. It's good to play around with the variation setting to get one that you like and feel comfortable with.
It's also important to choose your colors early on - keeping in mind printing costs. For the most popular method, screen printing, printing setup and the printing itself gets increasingly more expensive the more colors you use. It's therefore good to keep it a relatively low number of colors I chose 5 colors, which is probably the maximum you would want to use, unless directed otherwise by a brief. If you need help with choosing color schemes, I would recommend using Adobe Kuler for help.
It's now time to go over your lines using the Paintbrush Tool (B) with the settings we set earlier. This is where the pressure sensitivity of your graphics tablet will help. You also don't have to stick to your sketch lines, it's good if you have new ideas to implement them. If you look at my sketch next to my finished lines they are not the same.
It's also good to Group your lines together according to area by Right-click > Group. For instance, if you are drawing character-type design like myself I would group all the lines that make up the head area - this makes re-positioning areas quick and easy should you need to change this later on.
Another good tip is to change your Stroke Weight for different areas to add some detail. For instance changing to 0.25px on the top menu bar to add in little details.
The next step is to Create New Layer below your "lines" layer called "color". You also should Lock your "lines" layer like you did with your "scan" layer earlier to prevent accidental editing.
The next step is simply to color your lines! Use a combination of the Paintbrush Tool (B) to color in like you would on paper(fun!) and you can use the Pen Tool (P) for larger areas and to be more precise! For example, I used the Pen Tool to cover the area of the t-shirt by creating anchor points all around the outlines as it is a lot faster than coloring in with the brush. You can also add highlights using the other colors you are using. This, similar to changing your Stroke Weight when you were drawing your lines, will help add depth to your illustration.
Shown in the pictures is the separated colors I used as well as the line work to give you an idea of how to color You can tell which areas have been colored-in using the Paintbrush Tool (B) and the larger areas that have been colored using the Pen Tool (P).
4. Prepare Your File for Printing
Once you are done with the coloring and are happy with your illustration, you should highlight the entire illustration, every layer except the "scan layer". Then go to Object > Expand Appearance. This expands all your brush strokes into filled shapes and will allow you to re-size the illustration to any size without losing quality. When resizing strokes in illustrator it can result in the strokes being either too thick or thin, therefore this is a key step.
When everything is finished the natural next step is to of course go to print. It's very important however to first check all your colors are correct and that you haven't accidentally used more than the amount you decided on at the beginning - this can cause extra unneeded printing costs.
If the design is for yourself or for a client as part of a commission, it's always good to mock-up the design onto either a photo of a t-shirt, or a t-shirt vector template. You can find these all over the Internet available for free. This step is particularly important if the design is for a client, it always helps to be as professional as possible!
When sending the file to the printer, most will be okay with an AI file, some will prefer EPS. It's very important to always specify the exact proportions of the design as it would appear on a t-shirt and the positioning of it - you may feel that is obvious but the printer won't. It's also good to include the Pantone codes for each of the colors you used to make sure the printing is exact and the same as the design. If you want to or have the time you can select all the shapes of each color by selecting one shape and going to Select > Same > Fill Color and separate them all onto separate layers. This can make the process easier for the printer although is not always required.
Hey, That's One Awesome T-Shirt!
I hope this helped your process - whether you are thinking of starting up your own clothing line, or you're an illustrator and thinking of offering this service to clients. Bear in mind in the clothing industry, the design is arguably the most important thing, and therefore it is important to get it perfect!