Three buckets of size “convenience” introduce us to the subject of today: formats when saving images. And after speaking of photographic techniques, we move to formats with which we can save our photos, or our files. Luckily the world is varied, and various are the preferences and habits of users. The following article tries to do some’ of clarity about the formats, in that context it is better to use one or the other, and what changes from one format to another.
Today I wanted groped with the menu type Wikipedia, but it is only a virtuosity fanatics WordPress.
The GIF format was one of the first to be adopted for the web. The main difference between the GIF format and the rest of the formats is the poor availability of colors. In fact, with this format it can use up to 256. Saving an image that has multiple color will result in an image posterized 256 colors. Today we can say that, aided by the technological progress and the lines faster and faster, is a format left some’ apart, in favor of new technologies. But let's see the main features:
Compression: LZW. Non-destructive. It performs well with the areas of the same color.
Transparency: GIF format supports transparency in 1 bit: transparent the opaque, no antialiasing.
More: It can also create animated by setting different delays between a frame and the other.
Recommended application: Small animations for the web, graphic sites, logos, drawings.
Given the scarcity of colors that can be managed the same image saved in GIF will be lighter than any other format. Regarding the animations has often been supplanted by flash format, in which animation you can also insert sounds and more complex effects, without the limit of 256 colors.
The PNG format is in some respects one of the direct competitors of GIF. As the first support transparency, but still does not support animations. A few years ago, it was implemented a variation of the standard PNG (called APNG – Animated PNG) which made it possible to animate GIF PNG as if they were, but with the depth of color typical of PNG and with the possibility of the percentage of transparency. The initiative had little luck, and despite some software conform themselves to the format APNG remains a non-standard size. Let us now, however, the PNG format standard:
Color: Grayscale, Straight Flush, RGB and monochrome.
Transparency: Supports an alpha channel with 256 levels of transparency. When saving in “Straight Flush” and Monochrome”, no transparency.
Recommended application: Surely for web use. The edges and logos support 256 levels of transparency, is also used by designers for Flash animations, due to the greater versatility in color management.
The JPEG format is the format for amateur photo excellence. Virtually all cameras on the market save images in JPEG (o JPG, is the same). Eye, however, that it is a compressed format, namely that there is a loss, yet lightweight, in the information of photography. When the camera so provides, recommend the use of RAW, a format to be processed later for a nice looking image even in JPG. Let's see the features:
Color: Grayscale, E CMYK RGB.
Compression Type: JPG Owner, lossy. Algorithm is not suitable to represent continuous-tone images (form of annoying squares).
Recommended application: Photographs for the web, Amateur and Printing.
The TIFF format has some analogy with the GIF format. I remember in the 90's the first computer via fax forwardable, were saved in TIFF format. Here are some characteristic:
Color: RGB, CMYK, Grayscale and color, bitmap.
Compression Type: Lossless LZW.
Transparency: It, through an alpha channel 8 bit or via a vector path saved inside.
Recommended application: It is mainly used for printing, is a standard format and then recognized by most software.
The XCF, unlike all formats hitherto treated, is a format for the production. The most appropriate software to open this format is Gimp, the famous open source graphics editor. The defect (not so much the size, web surfing software) you can not save images with CMYK color format, but only RGB. For some time the developers are venturing into the long task of translating all the code in GEGL, that supports the CMYK color space. Let's see how it behaves:
Color: RGB, indexed, Grayscale, duotone, multichannel 8 Bit by canale.
Compression Type: Without loss.
Transparency: It, using alpha channel and clipping paths.
Recommended application: It is used primarily in the production, it is still a format that allows you after the closing of the file to find all the separate layers.
It will be understood that TIFF and XCF does not have a preview image formats because they are directed to the web.