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Archivos TIFF

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Archivos TIFF (.tif)TIFF es un formato flexible de imgenes de mapa de bits que prcticamente admiten todas las aplicaciones de pintura, edicin de imgenes y maquetacin de pginas. Asimismo, prcticamente todos los escneres de escritorio pueden producir imgenes TIFF. El formato TIFF admite archivos CMYK, RGB, de escala de grises, Lab, de color indexado y de mapas de bits con canales alfa y tintas planas. Puede seleccionar un canal de tinta plana al colocar un archivo TIFF Los canales de tintas planas aparecen en InDesign como tintas planas en el panel Muestras. Puede usar un programa de edicin de imgenes como Photoshop para crear un trazado de recorte si desea incorporar un fondo transparente para una imagen TIFF. InDesign admite trazados de recorte en imgenes TIFF y reconoce los comentarios OPI codificados.

Cmo guardar un archivo en formato TIFFTIFF es un formato flexible de imgenes rasterizadas (mapa de bits) que prcticamente admiten todas las aplicaciones de pintura, edicin de imgenes y diseo de pginas. 1. Elija Archivo > Guardar como, seleccione TIFF en el men Tipo (Windows) o Formato (Mac OS) y haga clic en Guardar. 2. En el cuadro de dilogo Opciones de TIFF, seleccione las opciones que desea y haga clic en OK. Profundidad de bits (slo 32 bits) Especifica la profundidad de bits (16, 24 o 32 bits) de la imagen guardada. Compresin de imagen Especifica un mtodo para comprimir los datos de la imagen compuesta. Si est guardando un archivo TIFF de 32 bits, puede especificar si el archivo se guardar con compresin de predictor, pero no dispone de la opcin para utilizar la compresin JPEG. La compresin de predictor ofrece una compresin mejorada mediante la reorganizacin de valores de coma flotante y funciona con las compresiones LZW y ZIP. Orden de pxeles Escribe el archivo TIFF con los datos de canales intercalados u organizados por planos. Antes Photoshop siempre escriba archivos TIFF con el orden de canal intercalado. En teora, en el archivo de orden Planar se puede escribir ms rpido, se puede leer ms rpido y ofrece una compresin un poco mejor. Los dos rdenes de canales son compatibles con versiones anteriores de Photoshop. Orden de bytes

Selecciona la plataforma en la que puede leerse el archivo. Esta opcin es til cuando no sabe con qu programa se abrir el archivo. Photoshop y las aplicaciones ms recientes pueden leer archivos mediante un orden de bytes de IBM PC o de Macintosh. Guardar pirmide de imagen Conserva la informacin de varias resoluciones. Photoshop no proporciona opciones para abrir archivos de varias resoluciones; la imagen se abre con la resolucin ms alta dentro del archivo. Sin embargo, Adobe InDesign y algunos servidores de imgenes permiten abrir formatos de varias resoluciones. Guardar transparencia Conserva la transparencia como un canal alfa adicional cuando el archivo se abre en otra aplicacin. La transparencia siempre se conserva cuando el archivo se vuelve a abrir en Photoshop. Compresin de capas Especifica un mtodo para comprimir datos para pxeles en capas (en contraposicin a los datos compuestos). Muchas aplicaciones no pueden leer datos de capa y los omiten al abrir un archivo TIFF. Photoshop, sin embargo, puede leer datos de capa en los archivos TIFF. Aunque los archivos que incluyen datos de capa tienen un tamao mayor que los que no los incluyen, al guardar los datos de capa se elimina la necesidad de guardar y gestionar un archivo PSD independiente para que contenga los datos de capa. Seleccione Descartar capas y guardar una copia para acoplar la imagen. Nota: para hacer que Photoshop le pregunte antes de guardar una imagen con varias capas, seleccione Preguntar antes de guardar archivos TIFF con capas en el rea Administracin de archivos del cuadro de dilogo Preferencias.

Image File Formats - TIF, JPG, PNG, GIF Which to use?The three most common image file formats, the most important for printing, scanning and internet use, are TIF, JPG and GIF. However, TIF cannot be used in internet browsers. All editor programs like Adobe Photoshop or Adobe Elements support these file formats, which will generally support and store images in the following color modes: Color data mode Bits per pixel TIF RGB - 24 or 48 bits, Grayscale - 8 or 16 bits, Indexed color - 1 to 8 bits, Line Art (bilevel)- 1 bit For TIF files, most programs allow either no compression or LZW compression (lossless, but is less effective for 24 bit color images). Adobe Photoshop also provides JPG or ZIP compression

too (but which greatly reduces third party compatibility of TIF files). "Document programs" allow ITCC G3 or G4 compression for 1 bit text (Fax is G3 or G4 TIF files), which is lossless and tremendously effective (small). PNG RGB - 24 or 48 bits, Grayscale - 8 or 16 bits, Indexed color - 1 to 8 bits, Line Art (bilevel) - 1 bit PNG uses ZIP compression which is lossless, and slightly more effective than LZW (slightly smaller files). PNG is a newer format, designed to be both verstile and royalty free, back when the LZW patent was disputed. JPG RGB - 24 bits, Grayscale - 8 bits JPEG always uses lossy JPG compression, but its degree is selectable, for higher quality and larger files, or lower quality and smaller files. GIF Indexed color - 1 to 8 bits GIF uses lossless LZW compression, effective on indexed color. GIF files contain no dpi information for printing purposes. Note that if your image size is say 3000x2000 pixels, then this is 3000x2000 = 6 million pixels (6 megapixels). If this 6 megapixel image data is RGB color (if 24 bits, or 3 bytes per pixel of RGB color information), then the size of this image data is 6 million x 3 bytes RGB = 18 million bytes. That is simply how large your image data is (see more). Then file compression like JPG or LZW can make the file smaller, but when you open the image in computer memory for use, the JPG may not still have the same image quality, but it is always still 3000x2000 pixels and 18 million bytes. This is simply how large your RGB image data is (megapixels x 3 bytes per pixel).

Best file types for these general purposes:Photographic Images Graphics, including Logos or Line art

Properties

Photos are continuous tones, 24 bit color or 8 bit Gray, no text, few lines and edges TIF or PNG (lossless compression and no JPG artifacts) JPG with a higher Quality factor can be decent.

Graphics are often solid colors, up to 256 colors, with text or lines and sharp edges PNG or TIF (lossless compression, and no JPG artifacts) TIF LZW or GIF or PNG (graphics/logos without gradients normally permit indexed color of 2 to 16 colors for smallest file size) TIF or GIF

For Unquestionable Best Quality Smallest File Size

Maximum Compatibility (PC, Mac, Unix) Worst Choice

TIF or JPG

256 color GIF is very limited color, and is a larger file than 24 bit JPG

JPG compression adds artifacts, smears text and lines and edges

These are not the only choices, but they are good and reasonable choices. Web pages require JPG or GIF or PNG image types, because that is all that browsers can show. On the web, JPG is the best choice (smallest file, with quality being less important than size) for photo images, and GIF is common for graphic images. GIF was designed for modems by CompuServe, for earliest 8 bit video, and so GIF contains no printing dpi information, and is out of date for 24 bit photos now, but GIF still works quite well for video graphics on the internet. Other than the web, TIF file format is the undisputed leader when best quality is required (when less than maximum quality is not a consideration). So TIF is very common in commercial or professional printing environments. High Quality JPG can be pretty good too, but don't ruin them by making them too small. If the goal is high quality, then only consider making JPG large instead, and plan your work so you can only save them one or two times. Adobe RGB color space may be OK for your home printer and profiles, but if you send your

pictures out to be printed, the mass market printing labs normally only accept JPG files and only process sRGB color space.

Difference in photo and graphics imagesPhoto images have continuous tones, meaning that adjacent pixels often have very similar colors, for example, a blue sky might have many shades of blue in it. Normally this is 24 bit RGB color, or 8 bit grayscale, and a typical color photo may contain perhaps 100,000 colors, out of the possible set of 16 million colors in 24 bit RGB color. Graphic images are normally not continuous tone (gradients are possible in graphics, but are not seen very often). Graphics are drawings, not photos, and they use relatively few colors, perhaps less than 16 colors in the entire image. In a color graphic cartoon, the entire sky will be only one shade of blue where a photo might have dozens of shades. Or a map for example is graphics, maybe 4 or 5 map colors plus 2 or 3 colors of text, plus blue water and white paper, often less than 16 colors overall. These few colors are well suited for Indexed Color. Normally the edges in graphics do not use anti-alaising - which would add numerous shades (graphics use high resolution to smooth jaggies instead). Scanners have three modes to create the image: color (for all color work), grayscale (like B&W photos), and lineart. Line art is a special case, only two colors (black or white, with no gray), for example clip art, fax, and of course text. However low resolution line art (like cartoons on the web) is often better as grayscale, to add aliasing to hide the jaggies. JPG files are very small files for continuous tone photo images, but JPG is poor for graphics. JPG requires 24 bit color or 8 bit grayscale, and the JPG artifacts are most noticeable in the hard edges of graphics or text. GIF files (and other indexed color files) are good for graphics, but are poor for photos (too few colors possible). Howe

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