Approve the Cookies
This website uses cookies to improve your user experience. By using this site, you agree to our use of cookies. Read More.
OK
Index  •   • New posts  •   • RTAT  •   • 'Best of'  •   • Gallery  •   • Gear  •   • Reviews
Guest
New posts  •   • RTAT  •   • 'Best of'  •   • Gallery  •   • Gear  •   • Reviews
Register to forums    Log in

 
FORUMS Community Talk, Chatter & Official Stuff The Lounge 
Thread started 16 Mar 2004 (Tuesday) 19:22
Search threadPrev/next
sponsored links
(this ad will go away when you log in as a registered member)

Jpeg test update

 
JZaun
Goldmember
2,488 posts
Joined Jan 2004
     
Mar 16, 2004 19:22 |  #1

CoolToolguy asked for a different pic. I chose a colored object with detail. I cannot see any degridation of color of detail after 80 save cycles. Since I would never modify and re-save a image any near 80 times I do not see jpeg re-compression issue being a negative factor im my decision to use raw or jpeg. I do think from other reading, that I should save a raw or tiff image if I think I am going to be changing it over and over!! or if I know in time to change the camera that it is a critical shot. With my skill level in PSE2 that is not going to happen any time soon. Here are 2 more pics, the orriginal and the 80th save.

original

IMAGE NOT FOUND
IMAGE IS A REDIRECT OR MISSING!
Byte size: ZERO | Content warning: NOT AN IMAGE


Copy 80
IMAGE NOT FOUND
IMAGE IS A REDIRECT OR MISSING!
Byte size: ZERO | Content warning: NOT AN IMAGE



This is part of my ongoing process to decide if I am going to shoot raw or Jpeg..Just FYI, for many reasons, jpeg is ahead but hasn't won as of yet. more reasons why later.

ONE interesting note!!! somewhere between the first copy and copy 20 the image grew in size and the image streatched length wise!

JZaun

JZaun



  
  LOG IN TO REPLY
sponsored links
(this ad will go away when you log in as a registered member)
Scottes
Trigger Man - POTN Retired
Avatar
12,842 posts
Likes: 6
Joined Nov 2003
Location: A Little North Of Boston, MA, USA
     
Mar 16, 2004 19:36 |  #2

Jerry, you must be doing something wrong. Or maybe I am.

I saved your original duck, and created an action
File... Open... 51duck-1-web.jpg
File... Save As...JPG set at quality 12 (the highest)
File... Close

I assigned F2 to the action to make it easy. After 80 runs of the action I got this:

IMAGE: http://www.itsanadventure.com/postimages/51duck-1-web2.jpg

I saw degradation in the ocean after 5 runs, quite clearly. The duck itself is still not too bad, considering the brutality of the test.

You can take my 100-400 L away when you pry it from my cold, dead fingers.
Scottes' Rum Pages - Rum Reviews And Info (external link)
Follower of Fidget - Joined the cult of HAMSTTR©

  
  LOG IN TO REPLY
JZaun
THREAD ­ STARTER
Goldmember
2,488 posts
Joined Jan 2004
     
Mar 16, 2004 19:42 |  #3

It appears that you are saving as web.. I was saving as xxx to hard drive. Something about resaving web size?? I don't know. I would never resave a web pic anyway only one from my file..???????????????


JZaun




  
  LOG IN TO REPLY
evilenglishman
Goldmember
1,184 posts
Likes: 1
Joined Jul 2003
     
Mar 16, 2004 19:42 |  #4

as with the previous example of the screw, the file size of your second image is almost double the size of the original


Click here to view and/or sign the petition (external link)

  
  LOG IN TO REPLY
Scottes
Trigger Man - POTN Retired
Avatar
12,842 posts
Likes: 6
Joined Nov 2003
Location: A Little North Of Boston, MA, USA
     
Mar 16, 2004 19:47 |  #5

This time I "Saved As" Jpg, not Save for Web. Check my Action.

The file size increase is expected. It will happen every time. JPG is a lossy format, and some data will be lost as it changes colors to make it easier to compress. Thus the algorithm runs different every time, and edges are made sharper each time, as can be seen in the ocean in my pic. Since this is a greater variation between pixels the algorithm won't be as efficient, and thus it ends up as a larger file. Every time.

Jerry, where you by chance opening "51duck.jpg" and Saving As "51duck2.jpg" every time? I opened "51duck.jpg" and saved over it as "51duck.jpg" overwriting the original. So I was opening the file I just compressed, and compressing it again.


You can take my 100-400 L away when you pry it from my cold, dead fingers.
Scottes' Rum Pages - Rum Reviews And Info (external link)
Follower of Fidget - Joined the cult of HAMSTTR©

  
  LOG IN TO REPLY
JZaun
THREAD ­ STARTER
Goldmember
2,488 posts
Joined Jan 2004
     
Mar 16, 2004 19:52 |  #6

I opened duck and saved as "duck1 " the opened and saved as duck 1 over duck 1. overwriting itself. I was dealing with the original pic. You are dealing with the web pic.

JZaun




  
  LOG IN TO REPLY
nomel
Member
200 posts
Joined Aug 2003
     
Mar 16, 2004 20:06 |  #7

PNG anyone?

Why doesn't anyone ever use png? It's lossless, and works great. Support 32 bit color and everything.




  
  LOG IN TO REPLY
Scottes
Trigger Man - POTN Retired
Avatar
12,842 posts
Likes: 6
Joined Nov 2003
Location: A Little North Of Boston, MA, USA
     
Mar 16, 2004 20:07 |  #8

A PM from Jerry:

My pic was resized for the web after being saved 80 times! Thats the difference.. You are resaving the web pic. It is already degridated by being downsized for the web.!

Good point. Yes, I was taking your resized image.

Hold on...

100% Crop from orignal TIFF, Saved as JPG quality 12, ONCE

IMAGE: http://www.itsanadventure.com/postimages/gooseheadjpgtest100_original.jpg

100% Crop from orignal TIFF, Saved as JPG quality 12, 25 TIMES
IMAGE: http://www.itsanadventure.com/postimages/gooseheadjpgtest100_25times.jpg

Still a big difference.

Now, I resized both for the web, from 500x500 to 200x200
IMAGE: http://www.itsanadventure.com/postimages/gooseheadjpgtest100_originalresized.jpg
IMAGE: http://www.itsanadventure.com/postimages/gooseheadjpgtest100_25timesresized.jpg

Who can tell? There IS degradation in the resized ones, but the resize algorithm hides it pretty well.

So if all you're going to do is view on the web, then JPG all the time. But if you ever print that original-been-JPGed-20-times image, you'll see a difference.

You can take my 100-400 L away when you pry it from my cold, dead fingers.
Scottes' Rum Pages - Rum Reviews And Info (external link)
Follower of Fidget - Joined the cult of HAMSTTR©

  
  LOG IN TO REPLY
Conk
Goldmember
Avatar
3,368 posts
Joined Jul 2002
Location: Cloverdale B.C.
     
Mar 16, 2004 20:07 |  #9

I'm going to just jump in here and ask,
when you are resaving the photo are you replacing the file or making a new one? You can resave the same file a million times but if you keep saving the file into a new name it will make a copy. Then I'm sure you'll start to see the image degrade.


Cloverdale Photography (external link)
Photos (external link)
More Photos (external link)

  
  LOG IN TO REPLY
Conk
Goldmember
Avatar
3,368 posts
Joined Jul 2002
Location: Cloverdale B.C.
     
Mar 16, 2004 20:09 |  #10

nomel wrote:
Why doesn't anyone ever use png? It's lossless, and works great. Support 32 bit color and everything.

File size?


Cloverdale Photography (external link)
Photos (external link)
More Photos (external link)

  
  LOG IN TO REPLY
Scottes
Trigger Man - POTN Retired
Avatar
12,842 posts
Likes: 6
Joined Nov 2003
Location: A Little North Of Boston, MA, USA
     
Mar 16, 2004 20:16 |  #11

Conk wrote:
nomel wrote:
Why doesn't anyone ever use png? It's lossless, and works great. Support 32 bit color and everything.

File size?

Ha. Space is cheap. It's time

Same 8-bit image saved as JPG and PNG.
JPG: 2 seconds, 2.4 Meg
PNG: 43 seconds, 5.4 meg

Ouch!


You can take my 100-400 L away when you pry it from my cold, dead fingers.
Scottes' Rum Pages - Rum Reviews And Info (external link)
Follower of Fidget - Joined the cult of HAMSTTR©

  
  LOG IN TO REPLY
evilenglishman
Goldmember
1,184 posts
Likes: 1
Joined Jul 2003
     
Mar 17, 2004 06:36 |  #12

Generally people don't use png because of its larger file size.
Most consider png to be an alternative to gif because of its support for transparency.
However the problem is that the most popular browsers don't have built in support for png transparency, they support png - just not the transparency part.
Hence the reason no one uses it (yet).


Click here to view and/or sign the petition (external link)

  
  LOG IN TO REPLY
slejhamer
Goldmember
Avatar
1,758 posts
Likes: 1
Joined Jun 2002
     
Mar 17, 2004 08:12 |  #13

My results are similar to Scottes':

http://www.photography​-on-the.net …ad.php?t=27611&​highlight=


Mitch

  
  LOG IN TO REPLY
JZaun
THREAD ­ STARTER
Goldmember
2,488 posts
Joined Jan 2004
     
Mar 17, 2004 08:39 |  #14

slejhamer


Your test is run the same way scottes was on his first test. Your original file was only 504X403 and the crop was 432X 355. I ran the test with a full size jpeg file and croped after the last save. I didn't find your file size but scottes second test was more like mine. I can blow any pic out of the water with a crop. Try it using a full size file. I think your results will be more like mine and scottes second test..

JZaun




  
  LOG IN TO REPLY
slejhamer
Goldmember
Avatar
1,758 posts
Likes: 1
Joined Jun 2002
     
Mar 17, 2004 09:11 |  #15

JZaun wrote:
slejhamer

Your test is run the same way scottes was on his first test. Your original file was only 504X403 and the crop was 432X 355. I ran the test with a full size jpeg file and croped after the last save. I didn't find your file size but scottes second test was more like mine. I can blow any pic out of the water with a crop. Try it using a full size file. I think your results will be more like mine and scottes second test..

JZaun

Hi Jerry. You are mistaken, but I should have been more clear in my post. The test was done using a full-size duplicate of the original 6mp image file. Only after the repeated saves did I crop at 100% and resize for the web, so the size of the web posts has no bearing. I can send you the full-size files if you wish (I saved full-size copies of #21 and #81), and you would see exactly the same thing as I have posted, just much bigger!

Besides, Scottes' second test after 25 saves looks much more like mine at 21 saves than it does yours. As he said, there is "still a big difference." :wink:

Still, this is something of an academic exercise and your point about JPEG quality is valid. For practical purposes, there is nothing wrong with shooting a JPEG, editing, and then saving it again. I prefer RAW for other reasons (ease of WB and exposure correction) but I save my final image in JPEG format and delete the TIFFs I use for editing. Much of the criticism of JPEG is overstated. 8)

Cheers!

P.S. You don't have the "save as a copy" box checked when the "save as" dialog opens, do you?


Mitch

  
  LOG IN TO REPLY
sponsored links
(this ad will go away when you log in as a registered member)

2,908 views & 0 likes for this thread
Jpeg test update
FORUMS Community Talk, Chatter & Official Stuff The Lounge 
AAA
x 1600
y 1600

Jump to forum...   •  Rules   •  Index   •  New posts   •  RTAT   •  'Best of'   •  Gallery   •  Gear   •  Reviews   •  Member list   •  Polls   •  Image rules   •  Search   •  Password reset

Not a member yet?
Registered members may log in to forums and access all the features: full search, image upload, follow forums, own gear list and ratings, likes, more forums, private messaging, thread follow, notifications, own gallery, all settings, view hosted photos, own reviews, see more and do more... and all is free. Don't be a stranger - register now and start posting!


COOKIES DISCLAIMER: This website uses cookies to improve your user experience. By using this site, you agree to our use of cookies and to our privacy policy.
Privacy policy and cookie usage info.


POWERED BY AMASS forum software 2.1forum software
version 2.1 /
code and design
by Pekka Saarinen ©
for photography-on-the.net

Latest registered member is CCYMINUM
800 guests, 440 members online
Simultaneous users record so far is 6430, that happened on Dec 03, 2017

Photography-on-the.net Digital Photography Forums is the website for photographers and all who love great photos, camera and post processing techniques, gear talk, discussion and sharing. Professionals, hobbyists, newbies and those who don't even own a camera -- all are welcome regardless of skill, favourite brand, gear, gender or age. Registering and usage is free.