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- Understanding how transparency works across the Adobe applications
- Deconstructing the Transparency panel
- Adding transparency to gradients
- Understanding how overprints and knockouts work
- Using a gradient or complex appearance as an opacity mask
- The rules of transparency flattening
- Working with complex regions
- Understanding the relationship between flattening and stacking order
- Creating and sharing flattener presets
- Saving PDF files and using the PDF/X standards
Skill Level Intermediate
Okay, so we know that during flattening, Illustrator has two levels that you can kind of say of rasterization. There are times when Illustrator is forced to rasterize things, because it simply has no choice and then there are times where Illustrator can rasterize things at will based on their complexity. So, if Illustrator finds these complex regions or areas that it has defined as being too complex or time-consuming to print, Illustrator may rasterize those areas to enhance print performance.
Now, in the case of the first set of rasterization where Illustrator has no option but to rasterize something in order to preserve the appearance, we really have no say in that matter. Remember the rule of flattening is that I have to get rid of the transparency, but I can't get rid of the transparency at the cost of changing the appearance of my artwork. So in those cases, if I have to rasterize something, that's just the way that it is. It's almost the same thing as if I were to actually have to bring it into Photoshop and print it from there. However, in the second case of rasterization, in an example where I may have a very, very complex piece of artwork and it may take a long time to print it, but I still really want all the elements remain vector and print at a higher quality, I do have some options in front of me.
In fact, in the flattening process itself, there are several different settings and in this movie I want to explore those settings with you, so you have a good understanding of what they do. And as we'll see later on, we can actually custom create our own set of flattener settings for any individual file or for specific workflows. So, I am going to start off by selecting this piece of artwork here in this file called forest.ai and I am going to go to the Object menu. I am going to choose Flatten Transparency. This brings up the Flatten Transparency dialog box and we have seen this before, but we just clicked OK and get rid of it, because we don't want to deal with the settings just yet, but now we've finally reached that time where we can talk about all these different settings.
Now at the very top of the dialog box here is the popup where it says Preset and right now Illustrator ships with three different presets, something called Low Resolution, Medium Resolution or High Resolution. I'll be honest with you, the word resolution there seems a little bit kind of misleading, because it doesn't necessarily mean that the art is low-resolution. This is just a term that Illustrator kind of coined, meaning low quality, medium quality or high quality. But we'll see actually that these presets are things that we may want to kind of create on our own and kind of do away with these.
But for now, all we need to know about the presets is that they actually specify different settings inside the dialog box. So for here, let's actually explore what these settings are. The first thing that I will talk about here is this first element here called Raster/Vector Balance. There is a slider here and right now the value is set to 75. Now, this is actually probably one of the most important aspects of dealing with flattening transparency. We had discussed the second level of rasterization, meaning Illustrator to look for these complex regions and choose to rasterize them based on how complex they are and how long they may take to print.
What this slider does is it allows us to gauge how far Illustrator will go when deciding to rasterize something. So, if we look over here at the slider, I am going to change this slider right now, kind of move it all the way to the top where the value here is 100 or where it says Vectors. The further I get towards the 100, I am telling Illustrator keep as much of the artwork as possible in vector form, meaning I'm willing to forgo the speed of how long will it take to print this in order to get more and more vector artwork and more high-quality output for my file.
The more that I take my slider move it down toward Rasters, I am telling Illustrator that if it ever encounters something that is even somewhat complex, go ahead and rasterize it. In other words, I might look at the Raster side of the slider and say the more I get closer to the number 0, the more I am telling Illustrator, print my file faster at the expense of quality. We can't really say that rasters here means bad quality and vectors means good quality, because as we will soon see, we have the ability to set what resolution things get rasterized there, right? We are not up to that point yet, but in theory, if I were to tell you that if you thought about images right now to Photoshop and for you a high-res image was 300 pixels per inch and I told Illustrator, if you find any complex region, I want you to rasterize it at 300 pixels per inch, then in theory my document is going to print at a high quality.
All we are really saying right now is that we can kind of control how much freedom Illustrator has to rasterize things. If I am closer to Raster, Illustrator has more freedom to immediately go ahead and find these complex regions and rasterize artwork. If I go towards vectors, I am telling Illustrator only use that when you really, really feel that we've run into something that was very, very difficult. Another way to think about the slider is that the closer I get towards 100, the fewer complex regions I am going to have. If I kind of scroll down over here towards Rasters, that means I will end up having more and more complex regions inside of my document that become rasterized.
Now, it's important to realize that on this slider alone though, there are two special settings. If I take this slider right now and I crank it all the way up to 100, this value of 100 is a very special setting. It allows me to basically tell Illustrator to disable this ability to rasterize things purely for performance reasons. In other words, if I have the Raster/ Vector Balance slider set at 100, that means that Illustrator will only rasterize things if there is no other way to preserve that appearance in vector form.
However, at this value right here, there is never a time where Illustrator will rasterize things for performance reasons. In other words, when I have my Raster/ Vector Balance slider set to 100, I am telling Illustrator I don't care if it takes you five days to print this, you need to keep everything vector. Now, the other special setting that you have is actually 0. When you choose to have your Raster/Vector Balance set to 0, that means you're telling Illustrator I want you to rasterize everything. It's almost the same thing as if I'd taken my file right now, brought the entire file into Photoshop, rasterized the whole thing, and then go ahead and print it.
Now, there may be times when you want to use both of these. You will notice for example that if you choose the High Resolution preset from Illustrator, the Raster/ Vector Balance value is set to 100. In other words, if you ever use the High Resolution setting, Illustrator will always go ahead and print your artwork as vector, if it can. It will never invoke that second level of rasterization just for performance reasons. And in addition, if for some reason Illustrator encounters some area of your artwork that cannot be preserved in vector format, it must rasterize it, it will rasterize it at 1200ppi.
Now, Illustrator is also pretty smart. It knows what kind of artwork your art is, so it could choose to rasterize them differently based on their content. So let's talk about what these two settings are over here. We have a Line Art and Text Resolution. That means if I have vector artwork or text and if for some reason those areas need to get rasterized, Illustrator will do so at 1200 pixels per inch, which is a very high resolution. If for some reason, it encounters an area that has a gradient or gradient mesh inside of it, because those areas are of continuous tone, they can be rasterized at a lower resolution.
So, those get rasterized at 300 pixels per inch. And again if you are familiar with Photoshop, you probably attribute the number of 300 pixels per inch as a high-resolution image. However, it's important to note that the default setting at Illustrator is this Medium Resolution setting. That has the Raster/Vector Balance slider set at 75, meaning if it does encounter some really complex areas, like in this forest example right here we identified over 30 regions that we are going to become rasterized, then that will happen here when that slider is in this setting right here.
Plus if it does have to rasterize that artwork, it will do so at 300 pixels per inch. If it's line art and text and if it's filled with a gradient or a mesh, it will rasterize that at 150 pixels per inch. The reason why Illustrator has this Medium Resolution setting set as its default is because this way for the majority of the artwork that you do, at least it will print out pretty quickly out of your printer. Adobes of the thinking that for the most part, the printing that you as a designer do is probably for proofing purposes, so it's going to be okay if some of the areas get rasterized. However, their intention is that if you're going to send this file off to a print service provider or to a printer who is then going to process it using a rip and print separations, that they will do so by using the High Resolution setting or maybe their own customized setting.
Now, let's take a look at some of these other settings that are here as well. We have something called Convert All Text to Outlines and something called Convert All Strokes to Outlines. They basically fall within the same concept. If you have a stroke that is inside of your document and let's say it goes from one side of the page to the other, but only section of that stroke right now falls into an area that's going to get rasterized. So, that means that in theory, part of that stroke is going to be preserved in vector form, whereas part of that stroke is going to end up being rasterized. Now, when things get rasterized, they sometimes show up a little bit chunkier or they look a bit more bold and that would mean that if you are looking at this line as it goes across the page, there might be parts of the line that look a little bit heavier than other parts.
To avoid that from happening, if for some reason artwork just has to go ahead and get rasterized, you can choose to convert all of your text and all of your strokes to outlines and that will, because it will convert everything to outlines, make all of your strokes and all of your texts just a little bit bolder, so that way it will match the appearance of the rasterized areas. In other words, it will result in your lines and your text maybe not being as crisp and sharp, but at least it will look consistent across your document. Now, there is another checkbox here called Clip Complex Regions. Now remember a complex region is an area inside of your document that Illustrator has identified that would be easier and faster to process as a raster image than preserve it on vector form.
It's that second level of rasterization. If Illustrator does choose to go ahead and rasterize an area, by choosing this option here called Clip Complex Regions, you're instructing Illustrator to go ahead now and create a clipping mask, meaning preserve the vector shape and then create a rasterized part of the fill and then use that raster image inside of the overall shape, meaning create a mask around that. This does create a more complex file, but it ensures that you don't have these weird discolorations that may occur inside of your final output.
My suggestion to you is to always leave this option turned on. Because even through it does slow down printing somewhat, at least it ensures that you don't see color shifts throughout your artwork. One thing to note by the way, if you crank your Vectors slider all the way up to the right where it's set to 100, notice that at that point Illustrator is not allowed to use that second level of rasterization and that's why you'll see at that value the Clip Complex Region setting is actually disabled. Finally, there are two other settings here. One is called Preserve Alpha Transparency. This is actually where we are using the Flatten Transparency setting here inside of Illustrator for needs that are really not aligned to printing.
What it does is that it actually preserves the fact that the artwork won't have a white background, but will have a transparent background so that if you have this overlaying another color, that other color will show through. In addition, you have Preserve Overprints and Spot Colors and when you have that checkbox turned on. Illustrator will do its best to preserve any spot colors that you might be using, even though there's transparency involved. And if there are overprints that are not actually overlapping on these transparent artwork, those overprints will also become preserved. So, that should give you a pretty good idea about what all these settings do here inside of the Flatten Transparency dialog box.
Towards the end of the chapter, we'll actually talk about how to create our own presets and that way we can use those presets very quickly on a job-by-job basis.