Setting Some Things About JPG Format Straight
Feb 21, 2018 13:42:55 #
stan0301 wrote:
I’ve taken over two million images—and to my own eyes have never seen detectable JPEG degradation—what I will say is JPEG is a printing format—RAW is a capture format—if the first thing you want to see is a processed image then shoot in JPEG—if you hope to better process than the algorithm built into your camera then shoot RAW
Stan
Stan
What does JPEG have to do with printing? It is a mechanism for compressing files for internet / computer storage and display.
Feb 21, 2018 14:12:20 #
You're welcome, bikertut. I'm glad this helped. Some try to make things a lot more complicated than they need to be. This one boils down to being very simple.
As was alluded to earlier in the thread, you could open the jpg file, save it as a .tif file, then just close the original jpg. Edit your .tif file and save the final output to a jpg and that will minimize any miniscule changes made by that save process.
--Bob
As was alluded to earlier in the thread, you could open the jpg file, save it as a .tif file, then just close the original jpg. Edit your .tif file and save the final output to a jpg and that will minimize any miniscule changes made by that save process.
--Bob
bikertut wrote:
My thanks to you and all who have posted here and ... (show quote)
Feb 21, 2018 14:45:50 #
John_F wrote:
Would the procedure 'manfacture' 8-bits for each original 8-bits. ...
The process is as simple as appending 8 zeros to the end of each 8-bit JPEG value. This way an 8-bit value of 01001011 (8-bit for 75) becomes 0100101100000000 (16-bit value of 19200 or 75x256.
In the initial conversion, all values have 8 zero bits appended. During editing of the 16-bit TIFF, the trailing eight bits can become non-zero.
Eventually, when you convert back to 8-bit, the extra 8 bits are either discarded or used to round off the values to the closest integer from 0 through 255.
Feb 22, 2018 18:31:53 #
Adding 00000000 bin is zero so the original 01001011 is unchanged. What if you have 10110010 and Photoshop must add a bit for each the string is now 1?0?1?1?0?0?1?0? . How does PS calculate these bits. It takes 3 bits from each side, derives a trinomial and calculates the new bit value. How is does this is encoded inside the software code and this you can not see. I continue to maintain that expanding a pixel bit depth requires bits to be manufactured in some way.
selmslie wrote:
The process is as simple as appending 8 zeros to t... (show quote)
Feb 22, 2018 18:42:26 #
John_F wrote:
Adding 00000000 bin is zero so the original 01001011 is unchanged. What if you have 10110010 and Photoshop must add a bit for each the string is now 1?0?1?1?0?0?1?0? . How does PS calculate these bits. It takes 3 bits from each side, derives a trinomial and calculates the new bit value. How is does this is encoded inside the software code and this you can not see. I continue to maintain that expanding a pixel bit depth requires bits to be manufactured in some way.
You don't add it, you append it - 01001011 (8 bits) becomes 0100101100000000 (16 bits).
Read it again.
Feb 22, 2018 23:30:35 #
selmslie wrote:
You don't add it, you append it - 01001011 (8 bits) becomes 0100101100000000 (16 bits).
Read it again.
Read it again.
Exactly, it may look like the same number, but the latter is way more accurate!
As a friend said a couple of days ago. There are three kinds of people. Those that can count, and those that can't!
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