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Mordy Golding demonstrates how to be more productive, efficient, and creative by taking advantage of Adobe Illustrator to create pixel-perfect web graphics and interactive Flash content. Illustrator CS4 for the Web investigates the pros and cons of pixel- and vector-based web graphics, demonstrates efficient workflows, and explores the creative options available in Illustrator. Mordy also covers design techniques, such as creating typography that works well on screen, adding reflections, and making Flash animations. He discusses new Illustrator CS4 features, including using multiple artboards, bringing art into Dreamweaver, and utilizing Flash Catalyst. Exercise files accompany the course.
In the world of pixel based web graphics, the most common file formats that you'll find is GIF or some people pronounce it 'JIF,' JPEG and PNG. There is also another raster format that's supported by Illustrator which is called WBMP or Wireless Bitmap. It's not nearly as popular. It's reserved for the older versions of cell phones. But in either case, let's take a look at the options that are offered for each of these file formats. I'll go to the File menu and I'll launch to Save for Web & Devices dialog box. Let's just focus right now on a 2-up version so you could see the original and also the optimized version of my artwork. I am going to go ahead and select this slice right here so we can see this Groundswell logo.
And let's take a look at some of the options that are available for the GIF file format. Now one of the things about the GIF file format is that it's really optimized for working with flat colors. For example logos and things like that. Any time you have gradients or photographic content, it doesn't really work that well and the reason why is because the GIF file can only contain a maximum of 256 colors. But here's the sweet thing about working with a GIF file. Of course we know that the name of the game when creating optimized web graphics is to get the best possible looking graphic but at the smallest file size. And yes, you can have a maximum of 256 colors inside of a GIF file, but the lower that you bring that number down, the smaller your file size can get.
For example take a look over here. I had this Groundswell logo and right now my file size is 9.4 k. But my Color setting is set to 256. Let me go ahead and change that to -- let's do something drastic and go down to 4. Sure, it doesn't look that great but I have also changed my file size down to 2.3. And this is really one of the great things about Save for Web. Instead of having to export this in many different formats and see what works well, I could just play with this particular setting until I get enough colors that it looks really good, but yet it also comes down in file size. For example here you can see that the logo itself looks pretty good. But the drop shadow here does not really look that great because there aren't enough colors to make that happen. So let me crank this up a little bit higher. Let's go to around 32 Colors. Now I have an acceptable drop shadow. My color looks great and I am able to save a couple of K on my image.
Let's take a look at some of the other settings available for GIF. First of all, it says here Selective. This is actually an algorithm that's used to reduce the number of colors. Now in my original, I am working with millions of colors that are right here. How do I take those millions of colors and make them fit within just 32 colors? Illustrator has several different methods to do that. Something called Selective, Perceptual, Adaptive and Restrictive. The Restrictive version only uses web safe colors. So I doubt you'll ever get anything you'll be happy with when you use that option. For the most part, I find the Selective version to be the best. What's really happening when you use Selective is Illustrator is looking at the overall graphic and it's selecting the best colors to use in order to preserve the appearance of the artwork as you've created it. Now there are also times when you go ahead and you choose to use fewer numbers of colors that Illustrator has to use some kind of dithering pattern in order to simulate those colors. Like for example notice that over here the drop shadow is really smooth while I have lots of colors to get that great gradation.
However, because I am only using 32 colors right here I start to see some artifacts in that drop shadow. By default, when you choose GIF as a file format inside of Illustrator, Illustrator use something called Diffusion Dither. However, you can choose between Pattern and Noise or you can turn off dithering all together. I don't suggest that one but there are times when depending on the colors that are used that the Noise option is better. What the Noise normally does is it adds kind of destructive pattern to that area so that you don't really see any artifacts. But I'll go back to the Diffusion setting right here. One of the really neat things about working with GIF files is that they can also have transparency settings inside of them. That means you can specify up to one color in your graphic to be transparent. We'll talk more about that in another movie.
You also have an option over here to choose Interlaced. What Interlaced does is it basically allows a large graphic to download in multiple passes. So it appears first in a web browser window as a lower res graphic and then over time it starts to res up and comes to full strength. So again because of these settings, the ability to add transparency and also the ability to limit the number of colors to save file size, the GIF file format works really great for logos or things that have flat color or even text for that matter. Now if you are dealing with something that's photographic in nature and really want to get as many colors as possible, the best format for you to choose in that case would be JPEG.
The main difference between JPEG and GIF are two things. First of all like we said before, the GIF format can only contain a maximum of 256 colors. JPEG can have millions of colors inside of it, but there is a catch. You see a GIF file saves file size by finding common areas of the same color. That's why it works great for artwork that has flat color. However, a JPEG is considered a lossy format, meaning that it basically takes a look at your artwork and it tries to find areas that may not be as important then it throws that data out of the file.
In fact, each time that you save a JPEG the quality degrades more and more. It's kind of taking a piece of artwork and making a photocopy of it and then making a photocopy of the photocopy and making a photocopy of that photocopy. Each time you make another copy of it, the artwork just does not look great. That being said, you can see a tremendous amount of file savings when working with JPEG and again it's mainly beneficial to be used on photographic content. When you do choose the JPEG option, you could choose exactly how much quality you would like to keep in that particular image. For example, a low quality image will store a lot more information out of the file.
It won't look that great. For example take a look over here; you can see lots of artifacts in the artwork. But you really get a large file savings. For higher quality, go ahead and choose something like very high or maximum. It will look great, but you may be faced with a larger file size. Here at the maximum level for example, it says over here 25k. That's a pretty big difference from the 3k option that we saw when we chose the low version. There are two other options here that are important to know about. Progressive is the same thing like interlacing was with GIF. It basically allows the file to be downloaded over time. There is also an option to include an ICC color profile with your artwork. I don't recommend this because not only does it add to your file size, there are very few web browsers that are available today that actually honor those color profiles.
For a third possible option as far as file formats go, you can choose the PNG option or PNG and there are 8-bit and 24-bit versions. But I am going to choose the 8-bit one. Basically the PNG file format combines the best of both worlds between GIF and JPEG. PNG files can support more colors, they also have transparency, and they're supported by most modern web browsers. If you take a look at the options presented for the PNG file format, they match closely to what you've seen with a GIF file format and just to close the loop on all bitmap based formats, if I go over here to what it says WBMP or Wireless Bitmap, I'll see that I can optimize this graphics specifically for the wireless bitmap format.
But again, it's very rare that you would want actually use this particular feature. Most of the mobile devices that are used today have the ability to support color graphics.
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