I have noticed that when resizing from JPEG, bird and animal eyes sometimes lose definition.
Recently tried making all or as many as possible edits from original JPEG saved as Tiff.
Significant improvement.
Ian McHenry
I have noticed that when resizing from JPEG, bird and animal eyes sometimes lose definition.
Recently tried making all or as many as possible edits from original JPEG saved as Tiff.
Significant improvement.
Ian McHenry
Every time you save a jpg you loose definition. The ideal scenario is to capture in RAW, edit in TIFF and save for web in jpg. only after all adjustments have been made,
I agree with Fabs. Also, the loss in a jpeg image is worse in the shadow areas, so if the eyes of the bird are dark, the jpeg compression will lose more information there.
I do raw capture, convert to 16 bit, edit in 16-bit and save images as 16-bit tif.
Roger
Thanks Fabs & Roger
Maybe one day I'll get my head around RAW !!!
Cheers: Ian Mc
Ian might want to try an experiment .... save a jpeg ten times ... the last you won't recognize !!! :)
Hi Al
Appreciate your input but I tried this after a previous suggestion from you along these lines.
There was very little difference between original and 10th edit !!!!
Sorry to be pedantic.
Cheers: Ian Mc
Hi Jim
Not really.
Sometimes, although not always, the resizing of an image saved as JPEG results in loss of eye definition.
But not always.
For the sake of continuity I have chosen to save as Tiff from JPEG as much as possible.(Not possible with Noiseware)
However I have taken up Al's suggestion and saved each previous image up to 10 saves all in JPEG.
Here is first save resized from a recent original otherwise unedited.
Cheers: Ian Mc
And here is 10th save ( each save from previous save all saved in JPEG)
Cheers: Ian Mc

Did you use 100% quality (i.e. no compression) for JPEG?
Hi Arash
I have Photoshop Elements.
Quality is Maximum 10 and Baseline Standard.
Cheers:Ian Mc
Not to pick nits, but JPEG is a compression method. There is no such thing as "no compression" for JPEG. 100% quality just means the least amount of compression. I believe that in Photoshop the quality setting of 100 gives a compression ratio of roughly 2.6:1.
There are plugins available for Photoshop like "Better JPEG" that offer nearly lossless import and export. The best thing to do is work with RAW>TIFF files up until saving for the web, which is the only reason to save as JPEG. If you don't want to deal with RAW files, save any new JPEG files immediately as TIFF or PSD and edit those files instead.
Cheers Kerry
That was what I said at the start !!!
JPEG to Tiff edits then finalise with JPEG.
Ian Mc
Handy if not much computer memory.
Ian this is not a good way to judge differences between the two. I'm sure you can come up with a compelling reason for using either.
The fact is you are throwing info with the jpeg and it only has 256 colors vs millions. We go to great lengths to work in 16 bit through out but jpeg is only 8 bit. For web presentation you might not see a difference that will leap out at you for most images. In my opinion it makes a significant difference.... just as it does lenses, cameras, techniques etc The image is like a chain ... as strong as its weakest link.
btw having said all of that one photographer comes to mind ... Moose Peterson. For the longest time he only shot JPEG. Cant think of any other.... btw one of the reason he cited were space in the cards and coming up with a good image as long as he nailed it in camera. He published a ton of images and was (is) on of the best.
Alfred,
A jpeg is still millions of colors. It has 8-bits/channel, so 24-bit color, with the compression losses of course.
Jpeg is an impressive technology and I think the original designers did a superb job. Saving and resaving a jpeg 10 times does lose information, but the information loss is dependent on the quality level. At the highest quality, the loss is pretty small. Another factor in information loss is round-off error. When you open an image and edit it (e.g. with a change levels or curves) in 8-bit, integer round-off loses a bit, so you are down to 7-bits per color. Then add the jpeg compression losses and you'll lose more. So those who have not tried this, try changing (for example) the middle levels slider up and down by one or two units each time you save and you'll find the degradation is greater.
Jpeg with its compression increases noise too, and more so in the shadow regions. Take the original image, then after a jpeg save, put the two into layers in photoshop, then change the layer type on top to difference, next flatten the layers and stretch it. That will show you where the differences are.
Also note there is a jpeg 2000 which will also do 16-bit, and has a newer algorithm.
Side note: gif format is lossless compression of maximum of 256 colors. It is great for black and white images and line drawing (graphs). Graphs generally come out smaller in gif than in jpeg, and there are no artifacts in the gifs.
But with disk space getting so low in cost, raw and 16-bit tifs don't cost much to save and backup these days. So I recommend saving DSLR images as 16-bit tifs after raw conversion. I also scan my 4x5 film and save as 16-bit tifs.
Ian, I don't just want to join the parade here but I must say, their right. You asked a question going in, your getting the right answer. I use to also shoot JPEG not wanting to "mess" with RAW. When I got my new Nikon I started using 35MB Tif out of the camera having much the same concern or problem you were having. I saw a big improvement and thought that was the end of the road. That's until Roger and others explained Tif or no, I was still in an 8 bit mode and a lot of info was missing from what the camera saw and recorded.
How did that effect my image? Let me count the ways. When I did finally convert to RAW (I have a very hard head) which was no big deal work wise, my colors looked better and my post production looked much better. Ever heard of posterization? You should read up on it. White balance and exposure compensation can be fixed/changed in RAW post production quickly and easily and more accurately. Heard the term "shooting to the right", you can only do that effectively shooting RAW. Try it - you'll like it AND be a better man for it. :D
Last edited by Bill McCrystyn; 03-24-2009 at 09:57 PM.
Thanks Bill
Another boost for RAW and one hard to argue with ( from a b. minded Scot !!!)
I have had the occasional foray into the Jpeg/RAW camera settings so will keep that in mind for another comparison trial.
Cheers: Ian Mc
Oh, an evil Scot. Here I thought you were an Irishman like me. No wonder you don't get it! :) Just kidding, just kidding.
Ha ha. Would you believe an Irish great, great g'father !!!
Slainte: Ian Mc