Shel even though I've been using digital file to print my slide images @ home for around 7 years, I have no first hand experience with the actual degradation due to multiple resaves in jpeg. I have read literature & taken several digital photography (Geo Lepp) & Photoshop workshops/classes & feel confident in stating my previous post re multiple saving in jpeg format. I don't know at what stage the degradation is discernable, so I can understand a statement that image degradation does not always occur when saving a jpeg, how is one to discern the degradation, even tho it has occurred?
I suppose if someone was interested in proving/disproving this, all some one would have to do is keep opening/resaving and review the image after every time - doing this both with and without making any changes to the image. I haven't done that. My money is on degradation due to resaving. Kenneth Waller ----- Original Message ----- From: "Shel Belinkoff" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Saturday, November 13, 2004 12:57 PM Subject: Re: Reducing File Size with Photoshop > Hi Ken, > > I'm just repeating what others have said. I'm far from an expert on the > subject, but, iirc, John and others made a good case for the point that > image degradation does not always occur when saving a JPEG, as noted in my > post below. Is John correct? Are you correct? I don't know. I'm not an > expert. Didn't even land the role to play one on TV <LOL> > > As to why *I* would resave if the file was just opened for viewing - if you > meant me specifically rather than that generic "you" - well, I wouldn't, > not intentionally, anyway. But there are many instances when *someone* > might - I've certainly done so unintentionally. There's the scenario where > a file may be opened and the viewewr wants to save it to another folder, or > to a disk or CD, and may choose to use the save command rather than the > copy command. Or maybe just hit the save button out of habit. > > The point, of course, isn't WHY someone might do this, but what happens > when it's done: does the image degrade? > > Shel > > > > [Original Message] > > From: Kenneth Waller <[EMAIL PROTECTED]> > > To: <[EMAIL PROTECTED]> > > Date: 11/13/2004 9:22:15 AM > > Subject: Re: Reducing File Size with Photoshop > > > > Shel, > > after you open a jpeg, & then resave it as a jpeg, whether you have made > any > > changes or not, you are causing more losses to the file. Why would you > > resave if you just opened it up and viewed it? > > > > > > Kenneth Waller > > > > ----- Original Message ----- > > From: "Shel Belinkoff" <[EMAIL PROTECTED]> > > To: <[EMAIL PROTECTED]> > > Sent: Saturday, November 13, 2004 10:10 AM > > Subject: Re: Reducing File Size with Photoshop > > > > > > > We had a discussion about this some time ago, and a couple of people > (John > > > Francis comes to mind as one) suggested that this is not always the > case, > > > and that degradation of image quality takes place only in certain > > > circumstances. My recollection is that if a JPEG has not been changed, > > but > > > just opened for vieweing and then saved, there is no image degradation. > I > > > also seem to recall that if only a small area has been changed, such as > > > making an adjustment to one feature in the image, only that portion > which > > > has been adjusted suffers. This seems like a good time to clear this up > >
