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Review the scanning techniques graphics professionals and photographers use, while delving into workflow considerations and the advanced image-quality controls available in most scanning software. Author Taz Tally explains the core concepts, such as how resolution and interpolation affect scans; introduces the industry-standard SilverFast scanning software; and shares the settings to achieve the best results from a scan. The course also covers keeping your scanner and its parts clean and free of dust, and includes a variety of start-to-finish scanning tasks.
For our first honest-to-goodness scan project let's start with doing a simple line art. In many ways, it's one of the simplest kinds of scans to perform in terms of the setup, but it takes some fairly sophisticated thinking in terms of your whole scan workflow as to how you actually want to construct your scan and what setting do you want to make. So it's a simple scan, but it takes some sophisticated thinking to really get it exactly right, and honest-to-goodness many people make the wrong decisions even scanning the simplest kinds of images like this. So we've got this line art image. Let's review what we mean by simple line art.
Simple line art is line art that is defined by the edge of the image. When we look at this image here, we can see we don't care what goes on in-between the edges. It's the edges that really define this image. Our goal here is to reproduce this edge as close as possible to what the original image is. If our goal is to take the original and then edit it, make it look different, we're going to go a whole different direction. But in this case, we have a high- quality original line art or logo, and we want to reproduce it. So our goal is to get this edge as close to the original as possible.
Now when we do this, remember we talked about setting up the general and then we're going to the frame. Our next setup decision is what kind of scan mode. High-quality scanner operators for a long time have known a trick about scanning line art, and that is, you scan it in grayscale and then you convert it to 1-bit black-and-white line art, scan it an 8 or 16-bit and then convert it to black-and-white later. We're actually going to use that technique, but not for the simple line art. We're going to use it for complex line art more on that later. What we want to do is we want to reproduce this edge right here and the sophisticated part of thinking moves us down the workflow line.
I am thinking, boy, would I like to convert that into vectors? In order for me to do that and get real high-quality vectors that don't require a lot of editing to make it look right, is I want to get this edge as sharp and as hard as and as consistent as I can, and to do that we're going to choose 1-bit black-and-white line art. That's the first choice. So we're going to end up with a nice hard edge and it's going to be identical to the current one. Remember, if we're going to edit the edge, we'll do something else. We're going to go to grayscale, but for just edge reproduction, that's the first important choice is 1-bit black-and-white line art.
Then as we move down here, we're going to name the file. This is how I like to name my scan files, a logical name and then like a mode or a bit depth, black-and-white which assumes 1-bit and then the size about 5x7 and then we're going to go with 600 pixels per inch for our first scan and then we're going to do two scans here, one at 600 and one at 1200. That's going to be the second critical choice that we make in terms of our settings here. The first one is 1-bit black-and- white line art and then since we're just working our way down the dialog boxes here, we can go Output and you can actually put in if you want to 5x7 if you want an exact 5x7 inch image.
With an image like this that frankly I am going to be taking the vectors anyway, so the dimensions of the image actually is going to be determined by the vectors that we create. doesn't make too much difference if we get exactly 5x7. If we were intending to print this and wanted exact borders and so forth at 5x7, you can designate it. Honestly, for this one, it doesn't make too much difference. So I'm just going to set this manually by eye and make sure I have got enough space going all the way around so that I don't impinge upon the image at all. But the next crucial setting is this one right here, resolution settings.
As much as I love SilverFast, I don't really like the way they have done the resolution and certainly I don't like the terminology which is dpi. What I am going to be using in this course is ppi, pixels per inch. If you remember our earlier discussions about resolution, I prefer to use resolution terminology that matches the building blocks of the image. We'll be creating a pixel-based image that's going to be 600 pixels per inch vertically and horizontally. So think of this as pixels per inch. It's a holdover from really where this program came from and a lot of the basis, the foundation, the knowledge come from prepress here, which is why by the way, this interface uses Q-Factor and it's multiplication factor based upon line screen.
I'll discuss that more a little bit later. Let's just skip that for now and let's just move right to pixels per inch. We're going to put in 600 pixels per inch here. Why are we choosing that, because the optical resolution of the scanner is 1200 pixels per inch. I am going one-half of that, which means that there will be very little interpolation. We should end up with a high-quality edge. If we go up with something between 600 and 1200 we're likely to get interpolation. That's why this is such a critical choice. A lot of line art that we intend to take to vectors doesn't require really small pixels.
It just requires a consistent edge. So I am going to go with 600 pixels per inch, 1-Bit Line Art, no scaling of this at all. We're not going to scale at all. We're just going to scan this image at 100%, not have the scanner do any magnification at all, and I am going to go ahead and click Scan, and oh, it looks like we've got to set on a multiple output. So let me just go up here for a second. Let's change this from Batch Mode to Normal mode. There we go! Back to frame and let's click Scan. See how I could tell that.
that was set at Batch Mode, because it had the multiple pictures of the scan there. So if that ever happens, just come up there to go back to the General frame and put on single mode of scan. All right there we go! I am going to click Scan, and then the name comes up and we're going to save this as a 600 ppi, and then TIFF. I don't want any interpolation. We're not going to be going with JPEG or anything like that. In fact, we're going to save all the black- and-white 1-bit line art images out as TIFFs. Remember the reason why you wouldn't want to go with a JPEG particularly here is you want to maintain that high-quality edge as much as possible and by saving it out as a JPEG you risk interpolating that edge from compression.
So the scanner is going to do its thing, convert all those edges to pixels. Here we go! Now we're going to go right back to scanner. I want to scan this one at 1200. I want to do two scans, because I want to show you the difference between the two and then scan. Now something interesting is you notice this scan is going to take quite a bit longer, even the scanner makes a different noise, and you notice the file size is going to be 4 times larger. Not twice, but four times larger. Why? Because we're doubling the horizontal and the vertical resolution.
So anytime you double the linear resolution from 600 to 1200, it's going to quadruple the scanning time and the file size. A lot of people think that when you're going from 6 to 12, you're just doubling, but you're doubling horizontal and vertical resolution. That's why everything goes up by a factor of four. Now what I would like to do now is just compare these two images. I want to zoom in on a similar edge right up here, and I always like to look at two places when I look at these images. I like to look around curved edges like that and I also like to look at any place that we've got like a hard edge which comes to a tip, something like that.
We'll zoom in on both of those. Let's start by zooming in right here and comparing the consistency of these two edges, and let me just move this over here, and there we go! Notice both of these edges have lots of good real nice consistency in terms of pixel placement and that's because we use the optical resolution of the scanner. We didn't allow the scanner do any magnification. Notice this is a 1.44 MB file, this is 6.63. It's four times larger as we talked about by doubling the horizontal and the vertical resolution.
Both of these images have nice consistent edges on them. Notice almost no interpolation. In fact, no interpolation at 600, because all we have done is we've just doubled the size of the pixels, but we haven't moved them because it's one-half the optical resolution scanner. The question becomes which do we need? The answer is this. if you're going to be printing this as a pixel-based image, then they're both about at 233 here, you see that? This is going to give you a finer edge at 1200 pixels per inch. So if you're going to print it as a pixel-based image, scan it 1200. 1200 is a good resolution if you want to print as a pixel-based image.
If you're going to convert this into a vector-based image, either one of these will work just fine, thank you. And if you know you're going to go to vector, there is no sense scanning at 1200, the 600 will work just as well when you convert it to vectors. To demonstrate this is we're going to convert this into vectors and I want to show you, and I am not going to step you through this process, I am just going to do it right now. When we come to our projects we'll talk more about how to actually do the conversion. I just want to do it quickly for you. There's our 600. Let's go back.
I am going to go to the 1200, and I am just going through this just to show you so you've actually seen it so you believe me that we're converting these images to vectors, and how it's going to work, because I want to compare these two. Notice how the 1200 takes longer, everything takes longer when you go from 600 to 1200. The question is, is it worth it? We're about to find out. Let's take this, move this over, this is the 1200. Over here, come over to the first one we did, the 600.
First of all, look at the number of control points along here. 1, 2, 3, 4, 5, 6, 7 down to the changing curve and they're 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, there is about twice the number of control points on the 1200. Let's zoom in and take a look. Look at the quality of that edge. Look at the quality of that edge. They're identical. In fact, when we look at the greatest detail area and here is where it really tells and something like this in the two images.
Notice the detail is just as good on the 600 as it is on the 1200. No question about it. Point being, folks when you've got a simple line art image like this with not a lot of detail, you can use half the optical resolution of the scanner and create just as good a vector-based image. In fact, this one is actually better, because it has so fewer pixels. It doesn't create as many control points and we just use default settings to convert it to vectors. The rule here then is one-half the optical resolution of the scanner and most scanners these days have optical resolutions of around 1200 or some multiple of that.
So 600 pixels per inch, and you've seen it here. It's proof that this image is not only equal to, but actually better because it has fewer control points in it from this one that was constructed at 1200 pixels per inch. All right, there's simple line art scanning going to vectors. But if you plan to scan this as pixels and leave it as pixels and then keep it and print it as pixels, then you'd go to 1200. But honestly, why would you do that when you could take it to vectors and then you have all that scalability while maintaining its quality. I'd like to just say a few more words about resolution and I want to show you something.
Down here remember we set the resolution we were working at 6 and 1200 pixels per inch. Notice that this software goes all the way up to 12,800 pixels per inch. Honestly, most people have been trained or they tend to think that, well, the higher the resolution, the better. I see lots of line arts images that are scanned at 2400 and 3200 and people might be inclined to go all the way up to 12,800. First of all that's interpolated resolution that high. So you can get all sorts of interpolation. But I think I've proven to you that you don't really even need 1200 if you intend to go to vectors.
The key is not how much resolution, particularly interpolated resolution you're going to be using. When you look at your scanner manual, you're going to see a couple of different numbers. One is going to be, maybe, it'll say hardware resolution or optical resolution. That's really the optical resolution of the scanner and probably it's going to be 1200, might be 2400. Then you're going to have a wide range of resolutions up to in this case like 12,000. The optical resolution of the scanner is not 12,800. It's not anywhere close to that. But point is that you don't need that resolution if you're going to be going to vectors, 600 is all you need for this kind of an image.
In fact, if you went all the way up to 8 ,000 or 12,000, you would be imparting so much interpolation that your edge would actually be lower quality and you'd end up with far more control points and the scans would take so much longer. No benefit at all. So this is one of those circumstances where less is indeed more. So I would encourage you to take a couple of line art images like this and practice with your scanner and the software and see which one gives you better results. is it 600, is it 800, is it 1200? I think you'll find that for most scanners these days 600 is going to work really good for these kinds of images.
But test with your scanner and your images.
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