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JPG vs PNG
- Thread starter D Cox
- Start date
If you save your JPEG at high resolutions there shouldn't be any visible difference on a monitor.A quick test to see if a PNG file looks different from a JPG on DPR.
JPG
PNG
JPG :
PNG :
Any difference on your monitor ?
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en.wikipedia.org
"JPG" covers a huge range of options, though, Don.A quick test to see if a PNG file looks different from a JPG on DPR.
JPG
PNG :
Any difference on your monitor ?
Yours was saved out of Photoshop CS6 at quality 12 and no sub-sampling.
At lower quality, there does appear to be a difference ... ;-)
JPG:
:-D
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Ted
DPR certainly messes with our images in various ways that are beyond me.
In post view, you image got changed from no chroma sub-sampling to full (both horizontal and vertical, aka 4:2:0 or (2x2). In the so-called "original" views, the px size on my screen is never what I posted whether I click the '+' cursor or not ...
I need to take another look at your OP's again from that POV ...
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Ted
Last edited by a moderator:
DavidWright2010
Veteran Member
If you subtract one from the other, there is a difference at the lowest level (0-8 values):
(This is a half-sized, compressed image. At full rez, and uncompressed, it's 26 mb, unsurprisingly)
David
(This is a half-sized, compressed image. At full rez, and uncompressed, it's 26 mb, unsurprisingly)
David
DavidWright2010
Veteran Member
The simple difference between the two images gives a black image for normal viewing conditions. If, in Photoshop, I go to "levels", and change the range from 0-255 to 0-8, I see this.If you subtract one from the other, there is a difference at the lowest level (0-8 values):
(This is a half-sized, compressed image. At full rez, and uncompressed, it's 26 mb, unsurprisingly)
David
So, many values are different between the 2 images by one count. (e.g. red channel 47 instead of 48)
David
Kendall Helmstetter Gelner
Forum Pro
To really see the differences, I tried opening the first flower image in the DPReview Gallery (just clicking on image, not link), zooming to 100%, then going to the next flower image...
On the second image, it was 2x the zoom, and would not let me pan across more than half the image!
When I did use the two "original size" links I did a 100% zoom there and flipped around a bit, they appeared identical (even in the green areas which is where I thought JPG artifacts might crop up).
On the second image, it was 2x the zoom, and would not let me pan across more than half the image!
When I did use the two "original size" links I did a 100% zoom there and flipped around a bit, they appeared identical (even in the green areas which is where I thought JPG artifacts might crop up).
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