Some random thoughts on this topic... As Shangara often suggests and is often mistaken about and taken out of context, when used correctly and in the right workflows - JPEG encoding of image data can be great and the benefits are huge and the problems may be outweighed. Instead of being something of scorn it should be appreciated for what it is...think about the name and it's origins.
Audiophiles probably have the same debates about MP3 encoding etc. <g> Yes, archival is something again - but some digital "stock photos" which customers buy are in JPEG and they may not get a better option...seems a shame when you purchase the data that it is not as good as it could possibly be (as the original unaltered data). Some folk may tend to think of JPEG as the file format when it is really JFIF or something else which uses JPEG compression. I find lossy encoding in EPS to be a less good option unless it is known/expected - as it may not be obvious that one is resaving a JPEG due to the file format being EPS and not "JPG". <g> ***It is often good to do colour component filtering to JPEG data if you are going to save it back into a lossless format and do further work (blur a duped layer set to color blend over the original flat layer data, perhaps masking edges or not etc). It is amazing how one can bring recreate individual channel detail and remove channel blocking etc (often this does not have much impact on the composite image, apart from desaturiating noise or fine colour detail which is why a mask is good). Even after all the other lossy compressions are applied, some publishing systems at some newspapers or other places may further compress image data on the way to the imagesetter - regardless of how many times it may have happened in the past (final page layouts or whatever). Often the final reproduction process hides these flaws in output ready work. I am really amused by an ad they used to play on the National Geographic Channel - it was all about a sports photog going digital and how much time he saves with digital...all he has to do is roughly crop and wire the image back to the newspaper with lot's of savings in time/material/money etc...the big joke is that he is piping back a RGB image which will be reproduced as a monotone shot in the paper...so his FTP is taking three times as long as should due to moving RGB data around when he should be sending greyscale! He probably JPEGed the RGB to a much greater degree than ideally needed to send the RGB image when a single channel send would probably have been smaller and quicker - with or without JPEGing. Stephen Marsh. =============================================================== GO TO http://www.prodig.org for ~ GUIDELINES ~ un/SUBSCRIBING ~ ITEMS for SALE
