Image File Types

It's kind of a nasty day in Atlanta. It's a good day for a podcast. Yeah, yeah, why don't we do one of those? Let's let's start it off with a little listener mail. This listener mail comes from Andrew. Andrew says, Hey, tech crew, I was just wondering what the difference is between the different image file types such as gift, jpeg, tiff, bitmap sixteen color, two fifty six color, twenty four bit. Any help you could give would be

much appreciated. Well, Andrew, that's what this podcast is all about. Different image file types. Yea, yeah, there are a lot of Actually you talked talked about a lot of different things. Um, there are several different file types and for good reason. I mean a lot of them are used for print and those are your TIFFs and EPs files, and there are lots and lots of other really highly specialized file a lot of proprietary ones, but those two are the

two you know, generic ones. And then there are things like uh, you know, used for the web, which are your gifts. I found out that's the way the creator pronounced it. You know, I've been calling a gift for a long time. Uh yeah, what is dot dot com is great for this kind of stuff and the JPEGs, and there are tons and tons and tons of other ones,

uh that are related to that. You know that you would find that you might stick in a word documentary, things like that bitmap images or pings right, um, And really most of this comes down to lossy versus lossless compression. So those of you who have listened to our podcasts on MP three's, you know that that is a an audio file compression format, and it's a lossy compression format, meaning that as you compress the file, you lose some

of the information in that file. So in the case of MP three's, that means that you might get an audio file that doesn't sound quite as good as the original recording, And of course, depending on the bit rate you choose, if you choose a really low one, it might sound really kind of poor compared to the original. Well, the same sort of thing holds true for image files.

If you have a lossy format, there's a chance that the image that you get, uh, isn't going to look as good as the original source that that you you know, the original version of that image. That's right. UM. Basically, in any image file, any digital image file, UM, it's a file that contains information. It's just like a word processing document. It's just like a music file. UM. Basically, you have data and you need something that will read

the data. And the way that data is organized and the file the program that you used to read the file. You know, those are all contingent on a number of different things, and all these different file formats are UM geared for specific purposes. For example, you wouldn't want to use a tiff file for a web page for a couple of reasons, one being that most browsers can't read TIF files. That would be my number one, that would

be way up there. But even if browsers could read them, you probably wouldn't want to use them because the file sizes are going to be much much larger than a JPEG of the same kind of picture. Yeah, TIFF stands for tagged image file format and UM it's it's very very popular because it's used it's used in instances where

you want high quality. It can actually store pages worth of information and it can actually include metadata information about that file UM, which is why it's used by you know, people like archivists museums often use these and they can be huge, huge, huge files, and you can you can use these also if you want to print images and

have the print quality be very high. Because something that looks good on your screen, I'm sure we're all familiar with this, when you print it out on on a printer, it may not look nearly as good in printed format as it did on a screen. And that's kind of the whole dots per inch thing. And I mean, there's there's a lot of different factors that go into that.

TIP files tend to be one of the ones that are are used heavily in the print industry, and uh EPs files encapsulated PostScript are also used heavily in the print industry. Now they don't. They're not often UM they don't have the ability to hold a lot of pages. It's basically one page age and it's often used with

UM with vector images more so than than TIFF files. Now, before I get into that, I would like to point out that what Jonathan was saying especially true for these print file formats like EPs and TIFF, because UM, these are formats that you are going to see UH used in high resolution situations where you have three hundred, six hundred, twelve hundred or even more UM dots or pixels per inch, depending on whether you're printing or actually viewing the file

and UM. And that's the thing is, I mean, they're they're often huge. Now, they don't absolutely have to be UM just like you can use one of the web typical file formats and have them be ginormous because they're you know, very large and size, you know, physical size and hold a lot of information. But I mean these are the kinds of UH formats that do particularly well UM now, and there there is that one difference in EPs and well most of these others um it can

actually support vector graphics. Now, what's a vector graphic you might ask, or graphic? UM? I was totally waiting for an airplane quote there anyway. UM, vector graphics are basically line arn't drawings that they're mathematical in shape. Say, you know, you can use Adobe Illustrator to create these or fireworks or some of those other programs, and you could maybe

use UM, you know, create a star for example. Well, if you're doing this in a vector graphics image program where you're actually drawing this by hand or you know, with a mouse, UM, you basically that's a mathematical representation of that drawing. It can be resized, it can be made larger or smaller as you need to, and it's

not going to cause any degradation in the file quality. UM, which is really cool because you can't do that with a raster or bitmap image because each of those little pixels you see on the screen are all that there. You can shrink them, but you can't make them larger because the computer is gonna have to make up stuff that goes in between those pixels. And it's just kind of a blue green. I can throw another blue green in here, Otherwise it just spreads out and you'd have

a lot of little dots. That's why if you blow up a picture that was shot at a specific size and you try to blow it up to make a poster out of it, you're gonna see a lot of artifacts and errors in that image. Is gonna look kind of blocky, it's gonna look the color is not gonna look right. Um. Yeah, there are a lot of problems if you try to go beyond what the resolution allows. And that's uh so, tiff and EPs are primarily used

for print now. The others are stuff that you probably see far more frequently, things like the jeff and jpeg and occasionally the ping and uh so ping that would be another lossless storage format. Yeah, so mostly, I mean it's it's it's funny because when you were talking about compression earlier, that's the aventually what we're doing with JPEGs and pings, I mean, to get them down on the web.

You know, file sizes on the web. We're a real problem when everybody was using dial up modems because you know, if you had these gigantic files on on your website, all these images, I mean, you're downloading every image that's

on a website. So if every file is you know, half a meg and size, then suddenly every web page you look at is fifty megs, and it's going to take ten minutes to look at and people aren't going to visit your website very often, right, Yeah, a delay of over a few seconds is pretty frustrating for the average web user, especially, I mean even now in broadband, we've become accustomed to speed, and when it starts to take longer, well we decide that's not a place worth

visiting and we go somewhere else. Um. So now PNG uses ZIP compression yea, which I used quite a bit in other forms of a file compression. But yeah, it's supposed to be. It's it's lostless and um, as long as you have the right uh, the right software to decode that to unzip, then you're fine. You can view it and there's no problem. Um. And of course that's one of those that's widely available. So that makes the

PNG format pretty attractive. It's still fairly rare. Um, it's not necessarily something you're gonna run into a lot compared to the JPEG and Jeff's. Yes, as a matter of fact, the PING was sort of supposed to be a competitor to the JEFF. UM. See that the Jeff uses l z W compression actually named for the people who invented it, lampl, Zev and Welch their last names. Um. See, the thing is the Jeff is owned by unities, uh, and you

can license it. As a matter of fact, if you have a website and you have Jeff's on it, you're supposed to obtain a license from unitis in order to do this. This is not necessarily a paid transaction. But the thing is, people said, you know what, I don't want I want to use something that is free for me to use, which is why people were using, Um, we're switching to JPEGs so often. But JPEGs do better with certain kinds of images because of the compression that

they use and Jeff's use. You know. Basically people use JPEGs for photos and Jeffs for drawings. Yeah. And the reason for that is that JPEGs are are better at handling images that have sort of a continuous color range in them. Um, they can handle images that have lots and lots of different colors. So if you were to take an image of say the sky, let'sen you take a photo of the sky, there's gonna be lots of

different and it's a sunny day. All right, there's gonna be a lot of different of versions of the color blue. It's not just gonna all be one blue color, you know, the same color of blue. Right, It's gonna be a gradient, especially like late in the day, you know, as the sun is setting more early in the day, when the sun is rising right where you'll you might get it, you know, darker towards the horizon or whatever. Uh, You're gonna get a lot of different versions of the color blue.

And with something like a JPEG that can handle that gradation, it can handle that continuous change of colors. Uh. And the compression format that JPEGs us is a lossy format, so you do lose information as you compress. But the nice thing about JPEG is you can control how compressed the file is. Yes, yes, that's true. So if you use a low level of compression, you know the file size is going to be larger. But on the other hand,

you're gonna retain more information. If you compress the heck out of it, you're gonna lose a lot of information, but the file size will be nice and tiny. You know. It's funny because um, these file formats have been in use for quite some time now, and there have been many efforts to try to upgrade them. I mean, paying is just one of them. JPEG two thousand is another. It's a refinement of the jpegh wealth theoretically it's a refinement.

It's actually a completely different way of compressing the file. And um, you know, the idea is to get it as you know, keep as much information as possible, um, you know, without creating artifacts, with creating a you know, giving a better color range. Um. The thing is that right at the moment, there's really nothing that's replacing the JPEG and the JEFF on the website despite these advances.

And we should also mention that, you know, we were talking about the JPEGs really good for for images that have continuous color gradations. Jeff's really good for images that don't have that, um have have maybe some uh some clearly defined images. Now Jeff is capable of showing up to two fifty six colors in a single image. If the image has more than two hundred and fifty six colors,

it's going to fudge a bit. It's gonna you're gonna end up with the compression, You're gonna end up having colors that are close to what the original color is supposed to be but aren't exactly the same, So just tend to be really good for things like graphics, not necessarily pictures. Um, pictures isn't like photographs, so JPEGs are

better for photos are better for for graphic images. You think about the fact that you should be able to see or at least your computer probably tells you you can see millions of colors, and Jeff is only showing you two hundred and fifty six of those colors. Probably gives you a good idea of why people are trying, you know, have tried to improve upon the the Jeff

is in UH file that now. UM. You know, one time people were really concerned about the two D sixteen Web safe colors, and I don't really see people talking about that nearly as often as they used to. UM. But basically, these were the two D and sixteen UH colors that could be rendered on both Windows and Macintosh platforms because UM, the gamma in those and in the two systems is a little bit different. UM. But you know,

you really don't see that nearly as often. And you also don't see the other big Jeff proponent, which was the animated Jeff I used to allow you too. Well, it still does allow you to create a Jeff that has multiple pan else. Now, of course people use flash and they don't really use you know, animated gifts anymore. But now he also asked about bitmap files. Now, bitmaps a proprietary image file format from Microsoft. Well, okay, bitmapped images are or raster images used in a generic sense.

I mean, jpeg is a bitmapped image, sure, but bitmap as a file form exactly. Yes, I'm glad you did clear that up so that that maybe heads off a little listener mail because we'll Yeah. So BMP is specifically is the uncompressed proprietary file format that Microsoft created. Um not,

you don't see a lot of it. I used to actually use bitmap images quite a quite a bit in my old job, and that was because the software we used it was all Microsoft Office software, and occasionally I would need to take images from the web or from from certain other kinds of files, whether they be um uh charts, graphs, pie charts, the sort of stuff. Sometimes bitmap was the best option to to go with when

importing it into something like power Point. I mean, it was on Microsoft UH format in the first place, so of course you would expect it to work pretty well within their suite of programs, and um, often I would find that that would create the best image for those

sorts of applications. Outside of that, haven't seen a whole lot of use for it, right right, Yeah, it's still in use though, I mean people, it's it's still I still see attachments as as dot b MP files from time to time, not very frequently, um, you know, so it's it's just less in use. And then he also brought up a bit depth to yes, yes, which has to do with color, right, yes, Yes, the amount of

basically the amount of colors in the image. And that's that's when you were talking about the two color sort in the in the jift fun like a one bit would be something that has to be black or white because it's either white or black. That's the one bit, So you know, like a zero and a one type of thing. Um, yeah, that's essentially what that refers to. The different bits kind of talk about the different levels of color. So I guess sixteen, but I think that's

gray scale. It would be the various versions of grass. I suppose you could have a sixteen bit color as well. Yeah, you gray scale I think is sixteen bit. Yeah, well, I mean it's it's basically the bit depth is uh. And it's not just an image that can have bit depth. I mean your your computer monitor has a bit depth and um, it's basically the range of color that is

able that it's able to display. So, I mean an image file can be limited to a certain amount of bit depth in which you know, and and that's good for a web image because if you have a uh, you know, a sixteen bit image and a thirty two bit image, you know, if you're trying to keep the file size down, you can limit the bit depth and would have reduced that just compressed it a little bit more to try to to keep the file size to a minimum. I decided to look it up just to

make sure. Yeah again heading off the listener, sixteen bits, Yeah, it actually uh, the tiff files, PNG files and uh, well, the TIP and P and g fils they can do gray scale as a eight or sixteen bits um JPEGs it's eight bits. So I knew I had heard about the sixteen bits somewhere, and then I had to look it up and see exactly where that was and uh, and it is important, it's just not the kind of thing that most people are thinking about probably when they're

when they're creating. Now there's the the braw UH format, which some people say isn't technically a format, um, but it's basically a capture mode on your on a lot of digital cameras, especially higher end digital cameras and uh, professional photographers. You know, probably just about everybody uses the raw setting and basically gives you everything that's coming through the lens. The biggest downside on the raw format is that every manufacturer has its own variation of the raw format.

So yeah, because it's not a it's not a standardized right. Since it's not standardized, that means that you know, the raw images you take with one digital camera from one manufacturer may not may not be at all the same as the kind that you take on a totally different camera from a totally different manufacturer, but it will give you a lot better quality and it is lossless, right,

So yeah, just keep that in mind. The that it is not a technical you know I s O certified file format, and you may find some other image files out there as well. There's things like PSD files which a photo or PSP which would be paint shop proh. Yes, so there are other proprietary files out there. Of course those aren't nearly as UM, you know, widespread as the JPEG and Jeff's yep, ye, working Jeff as much as I can to make up for my my your Jeff my gift gaff or was it my Jeff jaff? I'm

so confused now, yes, yeah, UM, a PSD. Actually, that's that's interesting that you would mention that, because UM designers are probably gonna be more familiar with the PSD file. UM. One of the cool things about working with Photoshop is that you can create files with multiple layers UM. Then you can save it as a variety of different files. Now, UM, a Photoshop document, when you're actually working with it, you can have tons and tons of different layers UM that

you can use to apply. For example, I'm using UH right now for one of the classes I'm taking for

my graduate degree. UM. I am basically marking up websites to talk about the different parts, and I am creating different layers that draw attention to different ones so that I can say, Okay, in this example, we're talking about sections A and G. In this example, we're talking about B, C, D N F. Well, in this case, I have multiple layers, and I can turn on the ones that I want to display, save the file, then turn those off and

turn the other ones on for the next one. Well, the problem is that when you leave the layers on, you can't save. It is really anything other than the Photoshop document. If you want to make a JPEG or a ping or whatever out of it, you're going to have to flatten the image in order to do that because it doesn't those file formats don't necessarily support multiple layers. But it is very cool and in that it allows

you to do that. And another one created by Adobe would be the uh PDF, a portable document format which so many people you use now UM and that is really an image in a lot of cases. You know, it can be a scan of an article. UM, it could be a form that allows you to fill it out, but it is you know, it's sort of pinch hits as a file format, an image file format in some cases.

One of the cool things about it is especially for businesses, which really why one of the reasons why they support it so much is that, um, you can't modify it. So if you stand out a thing, is they please review this. They can put notes on it, they can you know, say these different things, but they can't go change it and then send it out to people, which can be really infuriating when you're the creative person actually

making the documentary. Why didn't you send that out? The nice thing is not only not only do you not have to worry about the modifying it, but the software to view it is readily available. Yes, anyone can download a free viewer to view PDF files and it's built into browsers now as a plug in. Um. It's even supported widely in the operating systems now, at least far more than it was. That it's uh it's initial release, right.

I remember when you had to actually hunt down the little the plug in and and downloaded and and install it. It's not not the case anymore. Yeah. I doubt that Adobe technically considers it a you know, an image file format, but it sort of production well, yeah, I don't really have any other image file for well and true. I

hope that answers your question to your satisfaction. I guess that leads us to our second instance of listener mail, and this listener mail comes from Robert from San Antonio, Texas, where folks know what listener mail is supposed to sound like. He says, while working over the weekend, I was able

to catch up on several of your episodes. I've never written into a podcast before, but thought i could share some personal experience on an item which crosses over between your video game and stuff you can hook up to your TV podcasts that may interest your fans. I'm referring to the original Xbox. It can be modeled. It can be moded, which allows you to install specialized media playing software and to upgrade the hard drive. I currently have two of them and have a five d gigabyte hard

drive in each. This allows me to store tons of media locally. But more importantly, it has a built in n I C allowing network access. Using Xbox Media Center, I can stream media content from my media server, and with the addition of a new piece of software called play On, I have access to all sorts of online media contents such as streams from Hulu, PBS, ESPN, Crackle, Adults, Swim, and many many more. It plays a variety of video formats, including a v I, DIVIX x VID and many more.

As a bonus, it up converts to ten A d I, so the image on an h D t V is pretty good. So for a fraction of the cost of an ht PC or Apple TV, you get a networked media player that can stream media from within your network or even from online content providers. Really cool. These consoles are a decade old yet can still be considered a contender for King of Media Centers. Thanks and keep up

the good work, Robert. Yeah, Robert, that's a great point. Yes, you can modify your Xbox and create a media center out of it. Uh, just for you guys out there who are curious, I mean, not that it really matters anymore, because the Xbox is pretty much out of out of production anyway. It violates the warranty. Oh yes, Microsoft's not really thrilled with people who open up the Xbox and modify it. They can't really do anything to stop you.

It's not against the law. Um, if you were to modify your Xbox in such a way that it changes the way it behaves in online play, Microsoft could step in and and possibly deactivate your Xbox Live account. But apart from that, there's really no you know, no punishment for doing this, unless, of course, you screw up and ruin your xbox. I would I would add to that that I would appreciate it if you do this, do me in personal favor and don't electrocute yourself what you

could do. Yeah, don't you start mucking around with the enters of things that have Step one, don't have it plugged in. Step to be very careful when you whenever you try and modify any form of electronics, because even if something's unplugged doesn't that doesn't necessarily mean it can't hurt you. Yeah, I would recommend finding a guide, either

online or a book, and following those instructions very carefully. Um, you probably want to have a little experience with things like soldering, because often you have to solder certain news circuits in in order to get it to behave the way you want it to. But it is completely do it yourself sort of project that anyone can tackle with the right patients and uh and skill. Yeah, it's a challenging you know, involves a squirrel and attractor. But I can What did I get the wrong instructions? You need

to invite me over to your house. Sometimes I gotta see how you set up your entertainment system. So, Robert, thanks so much. If any of you have any tips or questions, comments, anything like that, you can write us our emailed This is tech stuff at how stuff works dot com. You can visit our blogs at hou stuf works dot com. And remember on Tuesday's one pm you can watch tech stuff live as Crispy and I bring you the latest tech news. That's one pm Eastern. That's right,

one pm Eastern. Thank you, Chrispy. That was very helpful. Um, yeah, please watch us because Lord knows we're not under enough pressure as it is. Uh. And if you want to learn are about image files and all things computer related, why don't you pop on over the house stuff works dot com and we will talk to you again really

soon for moralness and thousands of other topics. Does it how stuff works dot com And be sure to check out the new tech stuff blog now on the house stuff Works homepage, brought to you by the reinvented two thousand twelve camera. It's ready, are you