On 26/8/04 7:58 am, "Bob Croxford" wrote:
> Open a Jpeg in PS and although it appears as a Jpeg and will re-save as > a jpeg it is identical to the Tiff file you get when you save to Tiff. > Try saving it as a Tiff and tell me what the difference is? As far as I > know the only differences, when open, are in the tags. Change the one > that says 'I am a jpeg' to 'I am a Tiff' and that is what you get. > There seems to be a lot of confusion in this thread (I know I'm confused!). What Bob says above is correct, in as far as it goes. If you open up your RAW file and then save out to jpeg you are using lossy compression, and will introduce artefacts into your image and reduce image quality. Of course whether or not it is noticeable, even under close inspection, is the issue that is important. Opening that jpeg, and saving out to uncompressed Tiff will, as Bob says above, give you an identical image. However, that is not the same as opening the RAW file and then saving out directly to uncompressed Tiff � which of course will not involve lossy compression and therefore not introduce artefacts and a reduction in image quality. Therefore, depending on your starting point, jpeg and tiff are not identical. Douglas =============================================================== GO TO http://www.prodig.org for ~ GUIDELINES ~ un/SUBSCRIBING ~ ITEMS for SALE
