What impact does have file formats on images quality?

Question

I need to know what impact has different file formats on the quality of images with brief details.

Thank you

Answer 1

.jpg images are compressed and the compression often leaves "jpeg artifacts" in the image. These are visible signs of compression - often a blocky or speckled appearance.



.gif images can only display up to 256 colours - meaning that the quality of photo images is often affected.



.png images are compressed too but they often use "lossless compression" so the visual quality can be very high.



.bmp images are not compressed. They have the highest quality but also the largest file size.

Answer 2

JPEG and JPG are "lossy" formats, which means that you will lose a bit of quality in return for smaller file size. The more you compress the file, the smaller its size, but the lower the quality. (I'm not talking about compressing with WinZip or a similar utility, but rather the compression you achieve when you save the file in an image editing program like Photoshop.) BMP and GIF are not lossy, so will always retain the original quality. RAW generally gives the highest quality. It is a simple bitmap that renders every dot in the image at its best possible colour value. But it also is the largest file size. So, in general, you have to choose between small size and high quality. In practice, the difference in quality is often very small, and not worth worrying about. Hope this helps.

Answer 3

JPEG format = 'Joint Pictures Experts Group' format. Uses 'lossy' compression to reduce file size. The more you reduce the file size, the more 'artifacts' appear (blockiness, blurriness, etc), good for photographs and most other kinds of images. The compression artifacts are barely noticable or imperceptible on images saved at high enough quality.



GIF format = Image format for simple images. Limited to a palette of 255 colors. Supports animations. Complex images such as photos do not compress well under GIF due to the limited amount of colors you can use, as well as GIF is better at compressing images with large contiguous patches of color, when a lot of 'dithering' is employed (by trying to use too many colors) it starts to negate one of the key benefits of GIF (which are small file sizes). One of the colors in the palette can be fully transparent.



PNG format = Portable Network Graphics. A format for lossless compression. Has the biggest file size of all types listed here (except for BMP), but the compression preserves the full image quality. Also supports an 8-bit transparancy channel, allowing for 255 levels of transparency. PNG is a very good special purpose format and can even be used for photographs where it is essential to preserve the full image quality.



SVG format = Scalable Vector Graphics. Another special purpose format, designed for line art (such as cartoons and icons). As this is a vector format, many SVG images can be zoomed into infinitely and never become blocky or blurry.



BMP format = Bitmap format. An uncompressed image. Always in full quality. The file size is absolutely gigantic compared to other image formats so it is a bad idea to put it on the internet. PNG format is superior to BMP in all ways.

Answer 4

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Answer 5

Just read a book watching the identical reserve that has been converted to that movie. There are details in a book that we take for granted watching a movie. We do not have the sense of color or smell our intellects can create.

Answer 6

1

Answer 7

I suppose the more compression (which you can tell from file size) the fromat uses the worse the quality.

Answer 8

most professional printers do not like to use GIFs or JPGs as the printed quality is poor

Answer 9

Image file formats are standardized means of organizing and storing digital images. Image files are composed of either pixel or vector (geometric) data that are rasterized to pixels when displayed (with few exceptions) in a vector graphic display. The pixels that constitute an image are ordered as a grid (columns and rows); each pixel consists of numbers representing magnitudes of brightness and color.



JPEG/JFIF



JPEG (Joint Photographic Experts Group) is a compression method; JPEG-compressed images are usually stored in the JFIF (JPEG File Interchange Format) file format. JPEG compression is (in most cases) lossy compression. The JPEG/JFIF filename extension is JPG or JPEG. Nearly every digital camera can save images in the JPEG/JFIF format, which supports 8 bits per color (red, green, blue) for a 24-bit total, producing relatively small files. When not too great, the compression does not noticeably detract from the image's quality, but JPEG files suffer generational degradation when repeatedly edited and saved. The JPEG/JFIF format also is used as the image compression algorithm in many PDF files.

[edit] JPEG 2000



The TIFF (Tagged Image File Format) format is a flexible format that normally saves 8 bits or 16 bits per color (red, green, blue) for 24-bit and 48-bit totals, respectively, usually using either the TIFF or TIF filename extension. TIFF's flexibility can be both an advantage and disadvantage, since a reader that reads every type of TIFF file does not exist. TIFFs can be lossy and lossless; some offer relatively good lossless compression for bi-level (black&white) images. Some digital cameras can save in TIFF format, using the LZW compression algorithm for lossless storage. TIFF image format is not widely supported by web browsers. TIFF remains widely accepted as a photograph file standard in the printing business. TIFF can handle device-specific color spaces, such as the CMYK defined by a particular set of printing press inks. OCR (Optical Character Recognition) software packages commonly generate some (often monochromatic) form of TIFF image for scanned text pgs.



As far as videocameras are concerned, ARRI's Arriflex D-20 and D-21 cameras provide raw 3K-resolution sensor data with Bayern pattern as still images (one per frame) in a proprietary format (.ari file extension). Red Digital Cinema Camera Company, with its Mysterium sensor family of still and video cameras, uses its proprietary raw format called REDCODE (.R3D extension), which stores still as well as audio+video information in one lossy-compressed file.



PNG provides a patent-free replacement for GIF and can also replace many common uses of TIFF. Indexed-color, grayscale, and truecolor images are supported, plus an optional alpha channel.



PNG is designed to work well in online viewing applications like web browsers so it is fully streamable with a progressive display option. PNG is robust, providing both full file integrity checking and simple detection of common transmission errors. Also, PNG can store gamma and chromaticity data for improved color matching on heterogeneous platforms.



Some programs do not handle PNG gamma correctly, which can cause the images to be saved or displayed darker than they should be.[2]



Animated formats derived from PNG are MNG and APNG. The latter is supported by Mozilla Firefox and Opera and is backwards compatible with PNG.

[edit] GIF



GIF (Graphics Interchange Format) is limited to an 8-bit palette, or 256 colors. This makes the GIF format suitable for storing graphics with relatively few colors such as simple diagrams, shapes, logos and cartoon style images. The GIF format supports animation and is still widely used to provide image animation effects. It also uses a lossless compression that is more effective when large areas have a single color, and ineffective for detailed images or dithered images.



The BMP file format (Windows bitmap) handles graphics files within the Microsoft Windows OS. Typically, BMP files are uncompressed, hence they are large; the advantage is their simplicity and wide acceptance in Windows programs.

Answer 10

Try here:

http://www.scantips.com/basics09.html



I always use PNGs though